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Signed-off-by: tim-zju <21651152@zju.edu.cn>
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tim-zju
2016-12-22 14:37:10 +08:00
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CONTRIBUTING.md
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@@ -33,4 +33,4 @@ Note that code issues should be filed against the main kubernetes repository, wh
### Submitting Documentation Pull Requests
If you’re fixing an issue in the existing documentation, you should submit a PR against the master branch. Follow [these instructions to create a documentation pull request against the kubernetes.io repository](http://kubernetes.io/docs/contribute/create-pull-request/).
If you're fixing an issue in the existing documentation, you should submit a PR against the master branch. Follow [these instructions to create a documentation pull request against the kubernetes.io repository](http://kubernetes.io/docs/contribute/create-pull-request/).
LICENSE
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@@ -378,7 +378,7 @@ Section 8 -- Interpretation.
Creative Commons is not a party to its public
licenses. Notwithstanding, Creative Commons may elect to apply one of
its public licenses to material it publishes and in those instances
will be considered the “Licensor.” The text of the Creative Commons
will be considered the "Licensor." The text of the Creative Commons
public licenses is dedicated to the public domain under the CC0 Public
Domain Dedication. Except for the limited purpose of indicating that
material is shared under a Creative Commons public license or as
_includes/partner-script.js
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@@ -54,7 +54,7 @@
name: 'Skippbox',
logo: 'skippbox',
link: 'http://www.skippbox.com/tag/products/',
blurb: 'Creator of Cabin the first mobile application for Kubernetes, and kompose. Skippbox’s solutions distill all the power of k8s in simple easy to use interfaces.'
blurb: 'Creator of Cabin the first mobile application for Kubernetes, and kompose. Skippbox's solutions distill all the power of k8s in simple easy to use interfaces.'
},
{
type: 0,
@@ -89,7 +89,7 @@
name: 'Intel',
logo: 'intel',
link: 'https://tectonic.com/press/intel-coreos-collaborate-on-openstack-with-kubernetes.html',
blurb: 'Powering the GIFEE (Google’s Infrastructure for Everyone Else), to run OpenStack deployments on Kubernetes.'
blurb: 'Powering the GIFEE (Google's Infrastructure for Everyone Else), to run OpenStack deployments on Kubernetes.'
},
{
type: 0,
@@ -243,7 +243,7 @@
name: 'Samsung SDS',
logo: 'samsung_sds',
link: 'http://www.samsungsdsa.com/cloud-infrastructure_kubernetes',
blurb: 'Samsung SDS’s Cloud Native Computing Team offers expert consulting across the range of technical aspects involved in building services targeted at a Kubernetes cluster.'
blurb: 'Samsung SDS's Cloud Native Computing Team offers expert consulting across the range of technical aspects involved in building services targeted at a Kubernetes cluster.'
},
{
type: 1,
case-studies/index.html
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@@ -17,19 +17,19 @@ title: Case Studies
<div class="case-studies">
<div class="case-study">
<img src="/images/case_studies/pearson.png" alt="Pearson">
<p class="quote">“We chose Kubernetes because of its flexibility, ease of management and the way it improves our engineers’ productivity.”</p>
<p class="quote">"We chose Kubernetes because of its flexibility, ease of management and the way it improves our engineers' productivity."</p>
<!--<p class="attrib">— Chris Jackson, Director for Cloud Product Engineering, Pearson</p>-->
<a href="./pearson/">Read about Pearson</a>
</div>
<div class="case-study">
<img src="/images/case_studies/wikimedia.png" alt="Wikimedia">
<p class="quote">“With Kubernetes, we’re simplifying our environment and making it easier for developers to build the tools that make wikis run better.”</p>
<p class="quote">"With Kubernetes, we're simplifying our environment and making it easier for developers to build the tools that make wikis run better."</p>
<!--<p class="attrib">— Yuvi Panda, Operations Engineer, Wikimedia Foundation</p>-->
<a href="./wikimedia/">Read about Wikimedia</a>
</div>
<div class="case-study">
<img src="/images/case_studies/ebay.png" alt="eBay">
<p class="quote">Inside eBay’s shift to Kubernetes and containers atop OpenStack</p>
<p class="quote">Inside eBay's shift to Kubernetes and containers atop OpenStack</p>
<a href="http://www.nextplatform.com/2015/11/12/inside-ebays-shift-to-kubernetes-and-containers-atop-openstack/">Read about eBay</a>
</div>
<div class="case-study">
@@ -45,7 +45,7 @@ title: Case Studies
<section id="video">
<main>
<!--<div>-->
<!--<h3>“I don’t want to deploy software the old way ever again”</h3>-->
<!--<h3>"I don't want to deploy software the old way ever again"</h3>-->
<!--<p class="attrib">— Dylan Carney, Lead Software Engineer, Zulily</p>-->
<!--<img src="/images/case_studies/zulily.png" id="zulilyLogo" alt="zulily">-->
<!--</div>-->
case-studies/pearson.html
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@@ -13,13 +13,13 @@ title: Pearson Case Study
<section id="mainContent">
<main>
<div class="content">
<h3 id="caseStudyTitle">Using Kubernetes to reinvent the world’s largest educational company</h3>
<h3 id="caseStudyTitle">Using Kubernetes to reinvent the world's largest educational company</h3>
<p>
Pearson, the world’s education company, serving 75 million learners worldwide, set a goal to more than double that number to 200 million by 2025. A key part of this growth is in digital learning experiences, and that requires an infrastructure platform that is able to scale quickly and deliver products to market faster. So Pearson’s Cloud Technology team chose Kubernetes to help build a platform to meet the business requirements. </p>
Pearson, the world's education company, serving 75 million learners worldwide, set a goal to more than double that number to 200 million by 2025. A key part of this growth is in digital learning experiences, and that requires an infrastructure platform that is able to scale quickly and deliver products to market faster. So Pearson's Cloud Technology team chose Kubernetes to help build a platform to meet the business requirements. </p>
<div class="feature">
<img src="/images/case_studies/pearson.png" alt="Pearson">
<p class="quote">
“To transform our infrastructure, we had to think beyond simply enabling automated provisioning, we realized we had to build a platform that would allow Pearson developers to build manage and deploy applications in a completely different way. We chose Kubernetes because of its flexibility, ease of management and the way it would improve our engineers’ productivity.” </p>
"To transform our infrastructure, we had to think beyond simply enabling automated provisioning, we realized we had to build a platform that would allow Pearson developers to build manage and deploy applications in a completely different way. We chose Kubernetes because of its flexibility, ease of management and the way it would improve our engineers' productivity." </p>
<p class="attrib">— Chris Jackson, Director for Cloud Product Engineering, Pearson</p>
</div>
</div>
@@ -38,7 +38,7 @@ title: Pearson Case Study
<div class="bullet">
<h4>Why Kubernetes:</h4>
<ul>
<li>Kubernetes will allow Pearson’s teams to develop their apps in a consistent manner, saving time and minimizing complexity.</li>
<li>Kubernetes will allow Pearson's teams to develop their apps in a consistent manner, saving time and minimizing complexity.</li>
</ul>
</div>
<div class="bullet">
@@ -52,7 +52,7 @@ title: Pearson Case Study
<div class="bullet">
<h4>Results:</h4>
<ul>
<li>Pearson is building an enterprise-wide platform for delivering innovative, web-based educational content. They expect engineers’ productivity to increase by up to 20 percent.</li>
<li>Pearson is building an enterprise-wide platform for delivering innovative, web-based educational content. They expect engineers' productivity to increase by up to 20 percent.</li>
</ul>
</div>
</div>
@@ -63,9 +63,9 @@ title: Pearson Case Study
<main>
<div class="content">
<h4>Kubernetes powers a comprehensive developer experience</h4>
<p>Pearson wanted to use as much open source technology as possible for the platform given that it provides both technical and commercial benefits over the duration of the project. Jackson says, “Building an infrastructure platform based on open source technology in Pearson was a no-brainer, the sharing of technical challenges and advanced use cases in a community of people with talent far beyond what we could hire independently allows us to innovate at a level we could not reach on our own. Our engineers enjoy returning code to the community and participating in talks, blogs and meetings, it’s a great way for us to allow our team to express themselves and share the pride they have in their work.”</p>
<p>It also wanted to use a container-focused platform. Pearson has 400 development groups and diverse brands with varying business and technical needs. With containers, each brand could experiment with building new types of content using their preferred technologies, and then deliver it using containers. Pearson chose Kubernetes because it believes that is the best technology for managing containers, has the widest community support and offers the most flexible and powerful tools.“</p>
<p>Kubernetes is at the core of the platform we’ve built for developers. After we get our big spike in back-to-school in traffic, much of Pearson’s traffic will interact with Kubernetes. It is proving to be as effective as we had hoped,” Jackson says.</p>
<p>Pearson wanted to use as much open source technology as possible for the platform given that it provides both technical and commercial benefits over the duration of the project. Jackson says, "Building an infrastructure platform based on open source technology in Pearson was a no-brainer, the sharing of technical challenges and advanced use cases in a community of people with talent far beyond what we could hire independently allows us to innovate at a level we could not reach on our own. Our engineers enjoy returning code to the community and participating in talks, blogs and meetings, it's a great way for us to allow our team to express themselves and share the pride they have in their work."</p>
<p>It also wanted to use a container-focused platform. Pearson has 400 development groups and diverse brands with varying business and technical needs. With containers, each brand could experiment with building new types of content using their preferred technologies, and then deliver it using containers. Pearson chose Kubernetes because it believes that is the best technology for managing containers, has the widest community support and offers the most flexible and powerful tools."</p>
<p>Kubernetes is at the core of the platform we've built for developers. After we get our big spike in back-to-school in traffic, much of Pearson's traffic will interact with Kubernetes. It is proving to be as effective as we had hoped," Jackson says.</p>
</div>
</main>
</section>
@@ -74,9 +74,9 @@ title: Pearson Case Study
<main>
<div class="content">
<h4>Encouraging experimentation, saving engineers time</h4>
<p>With the new platform, Pearson will increase stability and performance, and to bring products to market more quickly. The company says its engineers will also get a productivity boost because they won’t spend time managing infrastructure. Jackson estimates 15 to 20 percent in productivity savings.</p>
<p>With the new platform, Pearson will increase stability and performance, and to bring products to market more quickly. The company says its engineers will also get a productivity boost because they won't spend time managing infrastructure. Jackson estimates 15 to 20 percent in productivity savings.</p>
<p>Beyond that, Pearson says the platform will encourage innovation because of the ease with which new applications can be developed, and because applications will be deployed far more quickly than in the past. It expects that will help the company meet its goal of reaching 200 million learners within the next 10 years.</p>
<p>“We’re already seeing tremendous benefits with Kubernetes — improved engineering productivity, faster delivery of applications and a simplified infrastructure. But this is just the beginning. Kubernetes will help transform the way that educational content is delivered online,” says Jackson.</p>
<p>"We're already seeing tremendous benefits with Kubernetes — improved engineering productivity, faster delivery of applications and a simplified infrastructure. But this is just the beginning. Kubernetes will help transform the way that educational content is delivered online," says Jackson.</p>
</div>
</main>
</section>
case-studies/wikimedia.html
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@@ -20,7 +20,7 @@ title: Wikimedia Case Study
<div class="feature">
<img src="/images/case_studies/wikimedia.png" alt="Wikimedia">
<p class="quote">
“Wikimedia Tool Labs is vital for making sure wikis all around the world work as well as they possibly can. Because it’s grown organically for almost 10 years, it has become an extremely challenging environment and difficult to maintain. It’s like a big ball of mud — you really can’t see through it. With Kubernetes, we’re simplifying the environment and making it easier for developers to build the tools that make wikis run better.”
"Wikimedia Tool Labs is vital for making sure wikis all around the world work as well as they possibly can. Because it's grown organically for almost 10 years, it has become an extremely challenging environment and difficult to maintain. It's like a big ball of mud — you really can't see through it. With Kubernetes, we're simplifying the environment and making it easier for developers to build the tools that make wikis run better."
</p>
<p class="attrib">— Yuvi Panda, operations engineer at Wikimedia Foundation and Wikimedia Tool Labs</p>
</div>
@@ -67,13 +67,13 @@ title: Wikimedia Case Study
<div class="content">
<h4>Using Kubernetes to provide tools for maintaining wikis</h4>
<p>
Wikimedia Tool Labs is run by a staff of four-and-a-half paid employees and two volunteers. The infrastructure didn't make it easy or intuitive for developers to build bots and other tools to make wikis work more easily. Yuvi says, “It’s incredibly chaotic. We have lots of Perl and Bash duct tape on top of it. Everything is super fragile.”
Wikimedia Tool Labs is run by a staff of four-and-a-half paid employees and two volunteers. The infrastructure didn't make it easy or intuitive for developers to build bots and other tools to make wikis work more easily. Yuvi says, "It's incredibly chaotic. We have lots of Perl and Bash duct tape on top of it. Everything is super fragile."
</p>
<p>
To solve the problem, Wikimedia Tool Labs migrated parts of its infrastructure to Kubernetes, in preparation for eventually moving its entire system. Yuvi said Kubernetes greatly simplifies maintenance. The goal is to allow developers creating bots and other tools to use whatever development methods they want, but make it easier for the Wikimedia Tool Labs to maintain the required infrastructure for hosting and sharing them.
</p>
<p>
“With Kubernetes, I’ve been able to remove a lot of our custom-made code, which makes everything easier to maintain. Our users’ code also runs in a more stable way than previously,” says Yuvi.
"With Kubernetes, I've been able to remove a lot of our custom-made code, which makes everything easier to maintain. Our users' code also runs in a more stable way than previously," says Yuvi.
</p>
</div>
</main>
@@ -84,13 +84,13 @@ title: Wikimedia Case Study
<div class="content">
<h4>Simplifying infrastructure and keeping wikis running better</h4>
<p>
Wikimedia Tool Labs has seen great success with the initial Kubernetes deployment. Old code is being simplified and eliminated, contributing developers don’t have to change the way they write their tools and bots, and those tools and bots run in a more stable fashion than they have in the past. The paid staff and volunteers are able to better keep up with fixing issues.
Wikimedia Tool Labs has seen great success with the initial Kubernetes deployment. Old code is being simplified and eliminated, contributing developers don't have to change the way they write their tools and bots, and those tools and bots run in a more stable fashion than they have in the past. The paid staff and volunteers are able to better keep up with fixing issues.
</p>
<p>
In the future, with a more complete migration to Kubernetes, Wikimedia Tool Labs expects to make it even easier to host and maintain the bots and tools that help run wikis across the world. The tool labs already host approximately 1,300 tools and bots from 800 volunteers, with many more being submitted every day. Twenty percent of the tool labs’ web tools that account for more than 60 percent of web traffic now run on Kubernetes. The tool labs has a 25-node cluster that keeps up with each new Kubernetes release. Many existing web tools are migrating to Kubernetes.
In the future, with a more complete migration to Kubernetes, Wikimedia Tool Labs expects to make it even easier to host and maintain the bots and tools that help run wikis across the world. The tool labs already host approximately 1,300 tools and bots from 800 volunteers, with many more being submitted every day. Twenty percent of the tool labs' web tools that account for more than 60 percent of web traffic now run on Kubernetes. The tool labs has a 25-node cluster that keeps up with each new Kubernetes release. Many existing web tools are migrating to Kubernetes.
</p>
<p>
“Our goal is to make sure that people all over the world can share knowledge as easily as possible. Kubernetes helps with that, by making it easier for wikis everywhere to have the tools they need to thrive,” says Yuvi.
"Our goal is to make sure that people all over the world can share knowledge as easily as possible. Kubernetes helps with that, by making it easier for wikis everywhere to have the tools they need to thrive," says Yuvi.
</p>
</div>
</main>
community.html
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@@ -24,8 +24,8 @@ title: Community
<h3>SIGs</h3>
<p>Have a special interest in how Kubernetes works with another technology? See our ever growing
<a href="https://github.com/kubernetes/kubernetes/wiki/Special-Interest-Groups-(SIGs)">lists of SIGs</a>,
from AWS and Openstack to Big Data and Scalability, there’s a place for you to contribute and instructions
for forming a new SIG if your special interest isn’t covered (yet).</p>
from AWS and Openstack to Big Data and Scalability, there's a place for you to contribute and instructions
for forming a new SIG if your special interest isn't covered (yet).</p>
</div>
<div class="content">
<h3>Events</h3>
docs/admin/admission-controllers.md
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@@ -126,7 +126,7 @@ For additional HTTP configuration, refer to the [kubeconfig](/docs/user-guide/ku
When faced with an admission decision, the API Server POSTs a JSON serialized api.imagepolicy.v1alpha1.ImageReview object describing the action. This object contains fields describing the containers being admitted, as well as any pod annotations that match `*.image-policy.k8s.io/*`.
Note that webhook API objects are subject to the same versioning compatibility rules as other Kubernetes API objects. Implementers should be aware of looser compatibility promises for alpha objects and check the “apiVersion” field of the request to ensure correct deserialization. Additionally, the API Server must enable the imagepolicy.k8s.io/v1alpha1 API extensions group (`--runtime-config=imagepolicy.k8s.io/v1alpha1=true`).
Note that webhook API objects are subject to the same versioning compatibility rules as other Kubernetes API objects. Implementers should be aware of looser compatibility promises for alpha objects and check the "apiVersion" field of the request to ensure correct deserialization. Additionally, the API Server must enable the imagepolicy.k8s.io/v1alpha1 API extensions group (`--runtime-config=imagepolicy.k8s.io/v1alpha1=true`).
An example request body:
@@ -151,7 +151,7 @@ An example request body:
}
```
The remote service is expected to fill the ImageReviewStatus field of the request and respond to either allow or disallow access. The response body’s “spec” field is ignored and may be omitted. A permissive response would return:
The remote service is expected to fill the ImageReviewStatus field of the request and respond to either allow or disallow access. The response body's "spec" field is ignored and may be omitted. A permissive response would return:
```
{
docs/admin/networking.md
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@@ -173,7 +173,7 @@ Lars Kellogg-Stedman.
[Nuage](http://www.nuagenetworks.net) provides a highly scalable policy-based Software-Defined Networking (SDN) platform. Nuage uses the open source Open vSwitch for the data plane along with a feature rich SDN Controller built on open standards.
The Nuage platform uses overlays to provide seamless policy-based networking between Kubernetes Pods and non-Kubernetes environments (VMs and bare metal servers). Nuage’s policy abstraction model is designed with applications in mind and makes it easy to declare fine-grained policies for applications.The platform’s real-time analytics engine enables visibility and security monitoring for Kubernetes applications.
The Nuage platform uses overlays to provide seamless policy-based networking between Kubernetes Pods and non-Kubernetes environments (VMs and bare metal servers). Nuage's policy abstraction model is designed with applications in mind and makes it easy to declare fine-grained policies for applications.The platform's real-time analytics engine enables visibility and security monitoring for Kubernetes applications.
### OpenVSwitch
docs/admin/rescheduler.md
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@@ -30,7 +30,7 @@ given the pods that are already running in the cluster
the rescheduler tries to free up space for the add-on by evicting some pods; then the scheduler will schedule the add-on pod.
To avoid situation when another pod is scheduled into the space prepared for the critical add-on,
the chosen node gets a temporary taint “CriticalAddonsOnly” before the eviction(s)
the chosen node gets a temporary taint "CriticalAddonsOnly" before the eviction(s)
(see [more details](https://github.com/kubernetes/kubernetes/blob/master/docs/design/taint-toleration-dedicated.md)).
Each critical add-on has to tolerate it,
the other pods shouldn't tolerate the taint. The tain is removed once the add-on is successfully scheduled.
@@ -57,4 +57,3 @@ and have the following annotations specified:
* `scheduler.alpha.kubernetes.io/tolerations` set to `[{"key":"CriticalAddonsOnly", "operator":"Exists"}]`
The first one marks a pod a critical. The second one is required by Rescheduler algorithm.
docs/getting-started-guides/logging.md
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@@ -79,7 +79,7 @@ root 479 0.0 0.0 4348 812 ? S 00:05 0:00 sleep 1
root 480 0.0 0.0 15572 2212 ? R 00:05 0:00 ps aux
```
What happens if for any reason the image in this pod is killed off and then restarted by Kubernetes? Will we still see the log lines from the previous invocation of the container followed by the log lines for the started container? Or will we lose the log lines from the original container's execution and only see the log lines for the new container? Let’s find out. First let's delete the currently running counter.
What happens if for any reason the image in this pod is killed off and then restarted by Kubernetes? Will we still see the log lines from the previous invocation of the container followed by the log lines for the started container? Or will we lose the log lines from the original container's execution and only see the log lines for the new container? Let's find out. First let's delete the currently running counter.
```shell
$ kubectl delete pod counter
docs/getting-started-guides/meanstack.md
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@@ -17,12 +17,12 @@ Thankfully, there is a system we can use to manage our containers in a cluster e
## The Basics of Using Kubernetes
Before we jump in and start kube’ing it up, it’s important to understand some of the fundamentals of Kubernetes.
Before we jump in and start kube'ing it up, it's important to understand some of the fundamentals of Kubernetes.
* Containers: These are the Docker, rtk, AppC, or whatever Container you are running. You can think of these like subatomic particles; everything is made up of them, but you rarely (if ever) interact with them directly.
* Pods: Pods are the basic component of Kubernetes. They are a group of Containers that are scheduled, live, and die together. Why would you want to have a group of containers instead of just a single container? Let’s say you had a log processor, a web server, and a database. If you couldn't use Pods, you would have to bundle the log processor in the web server and database containers, and each time you updated one you would have to update the other. With Pods, you can just reuse the same log processor for both the web server and database.
* Pods: Pods are the basic component of Kubernetes. They are a group of Containers that are scheduled, live, and die together. Why would you want to have a group of containers instead of just a single container? Let's say you had a log processor, a web server, and a database. If you couldn't use Pods, you would have to bundle the log processor in the web server and database containers, and each time you updated one you would have to update the other. With Pods, you can just reuse the same log processor for both the web server and database.
* Deployments: A Deployment provides declarative updates for Pods. You can define Deployments to create new Pods, or replace existing Pods. You only need to describe the desired state in a Deployment object, and the deployment controller will change the actual state to the desired state at a controlled rate for you. You can define Deployments to create new resources, or replace existing ones by new ones.
* Services: A service is the single point of contact for a group of Pods. For example, let’s say you have a Deployment that creates four copies of a web server pod. A Service will split the traffic to each of the four copies. Services are "permanent" while the pods behind them can come and go, so it’s a good idea to use Services.
* Services: A service is the single point of contact for a group of Pods. For example, let's say you have a Deployment that creates four copies of a web server pod. A Service will split the traffic to each of the four copies. Services are "permanent" while the pods behind them can come and go, so it's a good idea to use Services.
## Step 1: Creating the Container
@@ -37,7 +37,7 @@ To do this, you need to use more Docker. Make sure you have the latest version i
Getting the code:
Before starting, let’s get some code to run. You can follow along on your personal machine or a Linux VM in the cloud. I recommend using Linux or a Linux VM; running Docker on Mac and Windows is outside the scope of this tutorial.
Before starting, let's get some code to run. You can follow along on your personal machine or a Linux VM in the cloud. I recommend using Linux or a Linux VM; running Docker on Mac and Windows is outside the scope of this tutorial.
```shell
$ git clone https://github.com/ijason/NodeJS-Sample-App.git app
@@ -45,7 +45,7 @@ $ mv app/EmployeeDB/* app/
$ sed -i -- 's/localhost/mongo/g' ./app/app.js
```
This is the same sample app we ran before. The second line just moves everything from the `EmployeeDB` subfolder up into the app folder so it’s easier to access. The third line, once again, replaces the hardcoded `localhost` with the `mongo` proxy.
This is the same sample app we ran before. The second line just moves everything from the `EmployeeDB` subfolder up into the app folder so it's easier to access. The third line, once again, replaces the hardcoded `localhost` with the `mongo` proxy.
Building the Docker image:
@@ -83,7 +83,7 @@ $ ls
Dockerfile app
```
Let’s build.
Le's build.
```shell
$ docker build -t myapp .
@@ -139,7 +139,7 @@ After some time, it will finish. You can check the console to see the container
## **Step 4: Creating the Cluster**
So now you have the custom container, let’s create a cluster to run it.
So now you have the custom container, let's create a cluster to run it.
Currently, a cluster can be as small as one machine to as big as 100 machines. You can pick any machine type you want, so you can have a cluster of a single `f1-micro` instance, 100 `n1-standard-32` instances (3,200 cores!), and anything in between.
@@ -193,7 +193,7 @@ $ gcloud compute disks create \
Pick the same zone as your cluster and an appropriate disk size for your application.
Now, we need to create a Deployment that will run the database. I’m using a Deployment and not a Pod, because if a standalone Pod dies, it won't restart automatically.
Now, we need to create a Deployment that will run the database. I'm using a Deployment and not a Pod, because if a standalone Pod dies, it won't restart automatically.
### `db-deployment.yml`
@@ -231,7 +231,7 @@ We call the deployment `mongo-deployment`, specify one replica, and open the app
The `volumes` section creates the volume for Kubernetes to use. There is a Google Container Engine-specific `gcePersistentDisk` section that maps the disk we made into a Kubernetes volume, and we mount the volume into the `/data/db` directory (as described in the MongoDB Docker documentation)
Now we have the Deployment, let’s create the Service:
Now we have the Deployment, let's create the Service:
### `db-service.yml`
@@ -267,7 +267,7 @@ db-service.yml
## Step 6: Running the Database
First, let’s "log in" to the cluster
First, let's "log in" to the cluster
```shell
$ gcloud container clusters get-credentials mean-cluster
@@ -305,14 +305,14 @@ mongo-deployment-xxxx 1/1 Running 0 3m
## Step 7: Creating the Web Server
Now the database is running, let’s start the web server.
Now the database is running, let's start the web server.
We need two things:
1. Deployment to spin up and down web server pods
2. Service to expose our website to the interwebs
Let’s look at the Deployment configuration:
Let's look at the Deployment configuration:
### `web-deployment.yml`
@@ -371,7 +371,7 @@ At this point, the local directory looks like this
```shell
$ ls
Dockerfile
Dockerfile
app
db-deployment.yml
db-service.yml
docs/getting-started-guides/windows/index.md
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@@ -15,18 +15,18 @@ In Kubernetes version 1.5, Windows Server Containers for Kubernetes is supported
4. Docker Version 1.12.2-cs2-ws-beta or later
## Networking
Network is achieved using L3 routing. Because third-party networking plugins (e.g. flannel, calico, etc) don’t natively work on Windows Server, existing technology that is built into the Windows and Linux operating systems is relied on. In this L3 networking approach, a /16 subnet is chosen for the cluster nodes, and a /24 subnet is assigned to each worker node. All pods on a given worker node will be connected to the /24 subnet. This allows pods on the same node to communicate with each other. In order to enable networking between pods running on different nodes, routing features that are built into Windows Server 2016 and Linux are used.
Network is achieved using L3 routing. Because third-party networking plugins (e.g. flannel, calico, etc) don't natively work on Windows Server, existing technology that is built into the Windows and Linux operating systems is relied on. In this L3 networking approach, a /16 subnet is chosen for the cluster nodes, and a /24 subnet is assigned to each worker node. All pods on a given worker node will be connected to the /24 subnet. This allows pods on the same node to communicate with each other. In order to enable networking between pods running on different nodes, routing features that are built into Windows Server 2016 and Linux are used.
### Linux
The above networking approach is already supported on Linux using a bridge interface, which essentially creates a private network local to the node. Similar to the Windows side, routes to all other pod CIDRs must be created in order to send packets via the “public” NIC.
The above networking approach is already supported on Linux using a bridge interface, which essentially creates a private network local to the node. Similar to the Windows side, routes to all other pod CIDRs must be created in order to send packets via the "public" NIC.
### Windows
Each Window Server node should have the following configuration:
1. Two NICs (virtual networking adapters) are required on each Windows Server node - The two Windows container networking modes of interest (transparent and L2 bridge) use an external Hyper-V virtual switch. This means that one of the NICs is entirely allocated to the bridge, creating the need for the second NIC.
2. Transparent container network created - This is a manual configuration step and is shown in **_Route Setup_** section below
3. RRAS (Routing) Windows feature enabled - Allows routing between NICs on the box, and also “captures” packets that have the destination IP of a POD running on the node. To enable, open “Server Manager”. Click on “Roles”, “Add Roles”. Click “Next”. Select “Network Policy and Access Services”. Click on “Routing and Remote Access Service” and the underlying checkboxes
4. Routes defined pointing to the other pod CIDRs via the “public” NIC - These routes are added to the built-in routing table as shown in **_Route Setup_** section below
3. RRAS (Routing) Windows feature enabled - Allows routing between NICs on the box, and also "captures" packets that have the destination IP of a POD running on the node. To enable, open "Server Manager". Click on "Roles", "Add Roles". Click "Next". Select "Network Policy and Access Services". Click on "Routing and Remote Access Service" and the underlying checkboxes
4. Routes defined pointing to the other pod CIDRs via the "public" NIC - These routes are added to the built-in routing table as shown in **_Route Setup_** section below
The following diagram illustrates the Windows Server networking setup for Kubernetes Setup
![Windows Setup](windows-setup.png)
@@ -38,12 +38,12 @@ To run Windows Server Containers on Kubernetes, you'll need to set up both your
1. Windows Server container host running Windows Server 2016 and Docker v1.12. Follow the setup instructions outlined by this blog post: https://msdn.microsoft.com/en-us/virtualization/windowscontainers/quick_start/quick_start_windows_server
2. DNS support for Windows recently got merged to docker master and is currently not supported in a stable docker release. To use DNS build docker from master or download the binary from [Docker master](https://master.dockerproject.org/)
3. Pull the `apprenda/pause` image from `https://hub.docker.com/r/apprenda/pause`
3. Pull the `apprenda/pause` image from `https://hub.docker.com/r/apprenda/pause`
4. RRAS (Routing) Windows feature enabled
**Linux Host Setup**
1. Linux hosts should be setup according to their respective distro documentation and the requirements of the Kubernetes version you will be using.
1. Linux hosts should be setup according to their respective distro documentation and the requirements of the Kubernetes version you will be using.
2. CNI network plugin installed.
### Component Setup
@@ -110,7 +110,7 @@ route add 192.168.1.0 mask 255.255.255.0 192.168.1.1 if <Interface Id of the Rou
```
## Starting the Cluster
To start your cluster, you'll need to start both the Linux-based Kubernetes control plane, and the Windows Server-based Kubernetes node components.
To start your cluster, you'll need to start both the Linux-based Kubernetes control plane, and the Windows Server-based Kubernetes node components.
## Starting the Linux-based Control Plane
Use your preferred method to start Kubernetes cluster on Linux. Please note that Cluster CIDR might need to be updated.
## Starting the Windows Node Components
docs/hellonode.md
+11 -11
View File
@@ -12,7 +12,7 @@ title: Hello World on Google Container Engine
The goal of this codelab is for you to turn a simple Hello World node.js app into a replicated application running on Kubernetes. We will show you how to take code that you have developed on your machine, turn it into a Docker container image, and then run that image on [Google Container Engine](https://cloud.google.com/container-engine/).
Here’s a diagram of the various parts in play in this codelab to help you understand how pieces fit with one another. Use this as a reference as we progress through the codelab; it should all make sense by the time we get to the end.
Here's a diagram of the various parts in play in this codelab to help you understand how pieces fit with one another. Use this as a reference as we progress through the codelab; it should all make sense by the time we get to the end.
![image](/images/hellonode/image_1.png)
@@ -38,7 +38,7 @@ export PROJECT_ID="your-project-id"
Next, [enable billing](https://console.cloud.google.com/billing) in the Cloud Console in order to use Google Cloud resources and [enable the Container Engine API](https://console.cloud.google.com/project/_/kubernetes/list).
New users of Google Cloud Platform receive a [$300 free trial](https://console.cloud.google.com/billing/freetrial?hl=en). Running through this codelab shouldn’t cost you more than a few dollars of that trial. Google Container Engine pricing is documented [here](https://cloud.google.com/container-engine/pricing).
New users of Google Cloud Platform receive a [$300 free trial](https://console.cloud.google.com/billing/freetrial?hl=en). Running through this codelab shouldn't cost you more than a few dollars of that trial. Google Container Engine pricing is documented [here](https://cloud.google.com/container-engine/pricing).
Next, make sure you [download Node.js](https://nodejs.org/en/download/). You can skip this and the steps for installing Docker and Cloud SDK if you're using Cloud Shell.
@@ -79,7 +79,7 @@ You should be able to see your "Hello World!" message at http://localhost:8080/.
Stop the running node server by pressing Ctrl-C.
Now let’s package this application in a Docker container.
Now let's package this application in a Docker container.
## Create a Docker container image
@@ -109,7 +109,7 @@ Let's try your image out with Docker:
docker run -d -p 8080:8080 --name hello_tutorial gcr.io/$PROJECT_ID/hello-node:v1
```
Visit your app in the browser, or use `curl` or `wget` if you’d like :
Visit your app in the browser, or use `curl` or `wget` if you'd like :
```shell
curl http://localhost:8080
@@ -123,7 +123,7 @@ You should see `Hello World!`
curl "http://$(docker-machine ip YOUR-VM-MACHINE-NAME):8080"
```
Let’s now stop the container. You can list the docker containers with:
Let's now stop the container. You can list the docker containers with:
```shell
docker ps
@@ -180,7 +180,7 @@ You should get a Kubernetes cluster with three nodes, ready to receive your cont
![image](/images/hellonode/image_11.png)
It’s now time to deploy your own containerized application to the Kubernetes cluster!
It's now time to deploy your own containerized application to the Kubernetes cluster!
```shell
gcloud container clusters get-credentials hello-world
@@ -258,7 +258,7 @@ kubectl expose deployment hello-node --type="LoadBalancer"
**If this fails, make sure your client and server are both version 1.3. See the [Create your cluster](#create-your-cluster) section for details.**
The flag used in this command specifies that we’ll be using the load-balancer provided by the underlying infrastructure (in this case the [Compute Engine load balancer](https://cloud.google.com/compute/docs/load-balancing/)). Note that we expose the deployment, and not the pod directly. This will cause the resulting service to load balance traffic across all pods managed by the deployment (in this case only 1 pod, but we will add more replicas later).
The flag used in this command specifies that we'll be using the load-balancer provided by the underlying infrastructure (in this case the [Compute Engine load balancer](https://cloud.google.com/compute/docs/load-balancing/)). Note that we expose the deployment, and not the pod directly. This will cause the resulting service to load balance traffic across all pods managed by the deployment (in this case only 1 pod, but we will add more replicas later).
The Kubernetes master creates the load balancer and related Compute Engine forwarding rules, target pools, and firewall rules to make the service fully accessible from outside of Google Cloud Platform.
@@ -322,7 +322,7 @@ hello-node-714049816-ztzrb 1/1 Running 0 41m
Note the **declarative approach** here - rather than starting or stopping new instances you declare how many instances you want to be running. Kubernetes reconciliation loops simply make sure the reality matches what you requested and take action if needed.
Here’s a diagram summarizing the state of our Kubernetes cluster:
Here's a diagram summarizing the state of our Kubernetes cluster:
![image](/images/hellonode/image_13.png)
@@ -330,7 +330,7 @@ Here’s a diagram summarizing the state of our Kubernetes cluster:
As always, the application you deployed to production requires bug fixes or additional features. Kubernetes is here to help you deploy a new version to production without impacting your users.
First, let’s modify the application. On the development machine, edit server.js and update the response message:
First, let's modify the application. On the development machine, edit server.js and update the response message:
```javascript
response.end('Hello Kubernetes World!');
@@ -345,7 +345,7 @@ gcloud docker -- push gcr.io/$PROJECT_ID/hello-node:v2
Building and pushing this updated image should be much quicker as we take full advantage of the Docker cache.
We’re now ready for Kubernetes to smoothly update our deployment to the new version of the application. In order to change
We're now ready for Kubernetes to smoothly update our deployment to the new version of the application. In order to change
the image label for our running container, we will need to edit the existing *hello-node deployment* and change the image from
`gcr.io/$PROJECT_ID/hello-node:v1` to `gcr.io/$PROJECT_ID/hello-node:v2`. To do this, we will use the `kubectl set image` command.
@@ -364,7 +364,7 @@ hello-node 4 5 4 3 1h
While this is happening, the users of the services should not see any interruption. After a little while they will start accessing the new version of your application. You can find more details in the [deployment documentation](/docs/user-guide/deployments/).
Hopefully with these deployment, scaling and update features you’ll agree that once you’ve setup your environment (your GKE/Kubernetes cluster here), Kubernetes is here to help you focus on the application rather than the infrastructure.
Hopefully with these deployment, scaling and update features you'll agree that once you've setup your environment (your GKE/Kubernetes cluster here), Kubernetes is here to help you focus on the application rather than the infrastructure.
## Observe the Kubernetes Web UI (optional)
docs/tutorials/kubernetes-basics/cluster-intro.html
+1 -1
View File
@@ -90,7 +90,7 @@ title: Using Minikube to Create a Cluster
<p>A Kubernetes cluster can be deployed on either physical or virtual machines. To get started with Kubernetes development, you can use <a href="https://github.com/kubernetes/minikube">Minikube</a>. Minikube is a lightweight Kubernetes implementation that creates a VM on your local machine and deploys a simple cluster containing only one node. Minikube is available for Linux, Mac OS and Windows systems. The Minikube CLI provides basic bootstrapping operations for working with your cluster, including start, stop, status, and delete. For this bootcamp, however, you'll use a provided online terminal with Minikube pre-installed.</p>
<p>Now that you know what Kubernetes is, let’s go to the online tutorial and start our first cluster!</p>
<p>Now that you know what Kubernetes is, let's go to the online tutorial and start our first cluster!</p>
</div>
</div>
docs/tutorials/kubernetes-basics/deploy-intro.html
+2 -2
View File
@@ -86,9 +86,9 @@ title: Using kubectl to Create a Deployment
<div class="row">
<div class="col-md-8">
<p>For our first Deployment, we’ll use a <a href="https://nodejs.org">Node.js</a> application packaged in a Docker container. The source code and the Dockerfile are available in the <a href="https://github.com/kubernetes/kubernetes-bootcamp">GitHub repository</a> for the Kubernetes Bootcamp.</p>
<p>For our first Deployment, we'll use a <a href="https://nodejs.org">Node.js</a> application packaged in a Docker container. The source code and the Dockerfile are available in the <a href="https://github.com/kubernetes/kubernetes-bootcamp">GitHub repository</a> for the Kubernetes Bootcamp.</p>
<p>Now that you know what Deployments are, let’s go to the online tutorial and deploy our first app!</p>
<p>Now that you know what Deployments are, let's go to the online tutorial and deploy our first app!</p>
</div>
</div>
docs/tutorials/kubernetes-basics/explore-intro.html
+2 -2
View File
@@ -34,7 +34,7 @@ title: Viewing Pods and Nodes
<li>Networking, as a unique cluster IP address</li>
<li>Information about how to run each container, such as the container image version or specific ports to use</li>
</ul>
<p>A Pod models an application-specific “logical host” and can contain different application containers which are relatively tightly coupled. For example, a Pod might include both the container with your Node.js app as well as a different container that feeds the data to be published by the Node.js webserver. The containers in a Pod share an IP Address and port space, are always co-located and co-scheduled, and run in a shared context on the same Node.</p>
<p>A Pod models an application-specific "logical host" and can contain different application containers which are relatively tightly coupled. For example, a Pod might include both the container with your Node.js app as well as a different container that feeds the data to be published by the Node.js webserver. The containers in a Pod share an IP Address and port space, are always co-located and co-scheduled, and run in a shared context on the same Node.</p>
<p>Pods are the atomic unit on the Kubernetes platform. When we create a Deployment on Kubernetes, that Deployment creates Pods with containers inside them (as opposed to creating containers directly). Each Pod is tied to the Node where it is scheduled, and remains there until termination (according to restart policy) or deletion. In case of a Node failure, identical Pods are scheduled on other available Nodes in the cluster.</p>
@@ -117,7 +117,7 @@ title: Viewing Pods and Nodes
<p>You can use these commands to see when applications were deployed, what their current statuses are, where they are running and what their configurations are.</p>
<p>Now that we know more about our cluster components and the command line, let’s explore our application.</p>
<p>Now that we know more about our cluster components and the command line, let's explore our application.</p>
</div>
<div class="col-md-4">
docs/tutorials/kubernetes-basics/expose-intro.html
+3 -3
View File
@@ -28,7 +28,7 @@ title: Using a Service to Expose Your App
<div class="col-md-8">
<h3>Kubernetes Services</h3>
<p>While Pods do have their own unique IP across the cluster, those IP’s are not exposed outside Kubernetes. Taking into account that over time Pods may be terminated, deleted or replaced by other Pods, we need a way to let other Pods and applications automatically discover each other. Kubernetes addresses this by grouping Pods in Services. A Kubernetes <b>Service</b> is an abstraction layer which defines a logical set of Pods and enables external traffic exposure, load balancing and service discovery for those Pods.</p>
<p>While Pods do have their own unique IP across the cluster, those IP's are not exposed outside Kubernetes. Taking into account that over time Pods may be terminated, deleted or replaced by other Pods, we need a way to let other Pods and applications automatically discover each other. Kubernetes addresses this by grouping Pods in Services. A Kubernetes <b>Service</b> is an abstraction layer which defines a logical set of Pods and enables external traffic exposure, load balancing and service discovery for those Pods.</p>
<p>This abstraction will allow us to expose Pods to traffic originating from outside the cluster. Services have their own unique cluster-private IP address and expose a port to receive traffic. If you choose to expose the service outside the cluster, the options are:</p>
<ul>
@@ -70,7 +70,7 @@ title: Using a Service to Expose Your App
<div class="row">
<div class="col-md-8">
<p>A Service provides load balancing of traffic across the contained set of Pods. This is useful when a service is created to group all Pods from a specific Deployment (our application will make use of this in the next module, when we’ll have multiple instances running).</p>
<p>A Service provides load balancing of traffic across the contained set of Pods. This is useful when a service is created to group all Pods from a specific Deployment (our application will make use of this in the next module, when we'll have multiple instances running).</p>
<p>Services are also responsible for service-discovery within the cluster (covered in <a href="/docs/user-guide/connecting-applications/#accessing-the-service">Accessing the Service</a>). This will for example allow a frontend service (like a web server) to receive traffic from a backend service (like a database) without worrying about Pods.</p>
@@ -120,7 +120,7 @@ title: Using a Service to Expose Your App
<p>Labels can be attached to objects at the creation time or later and can be modified at any time.
The kubectl run command sets some default Labels/Label Selectors on the new Pods/ Deployment. The link between Labels and Label Selectors defines the relationship between the Deployment and the Pods it creates.</p>
<p>Now let’s expose our application with the help of a Service, and apply some new Labels.</p>
<p>Now let's expose our application with the help of a Service, and apply some new Labels.</p>
</div>
</div>
<br>
docs/tutorials/kubernetes-basics/scale-intro.html
+1 -1
View File
@@ -101,7 +101,7 @@ title: Running Multiple Instances of Your App
<div class="row">
<div class="col-md-8">
<p> Once you have multiple instances of an Application running, you would be able to do Rolling updates without downtime. We’ll cover that in the next module. Now, let’s go to the online terminal and scale our application.</p>
<p> Once you have multiple instances of an Application running, you would be able to do Rolling updates without downtime. We'll cover that in the next module. Now, let's go to the online terminal and scale our application.</p>
</div>
</div>
<br>
docs/tutorials/kubernetes-basics/update-intro.html
+1 -1
View File
@@ -116,7 +116,7 @@ title: Performing a Rolling Update
<div class="row">
<div class="col-md-8">
<p> In the following interactive tutorial we’ll update our application to a new version, and also perform a rollback.</p>
<p> In the following interactive tutorial we'll update our application to a new version, and also perform a rollback.</p>
</div>
</div>
<br>
docs/tutorials/stateful-application/zookeeper.md
+176 -176
View File
@@ -11,15 +11,15 @@ title: Running ZooKeeper, A CP Distributed System
---
{% capture overview %}
This tutorial demonstrates [Apache Zookeeper](https://zookeeper.apache.org) on
Kubernetes using [StatefulSets](/docs/concepts/abstractions/controllers/statefulsets/),
[PodDisruptionBudgets](/docs/admin/disruptions/#specifying-a-poddisruptionbudget),
This tutorial demonstrates [Apache Zookeeper](https://zookeeper.apache.org) on
Kubernetes using [StatefulSets](/docs/concepts/abstractions/controllers/statefulsets/),
[PodDisruptionBudgets](/docs/admin/disruptions/#specifying-a-poddisruptionbudget),
and [PodAntiAffinity](/docs/user-guide/node-selection/).
{% endcapture %}
{% capture prerequisites %}
Before starting this tutorial, you should be familiar with the following
Before starting this tutorial, you should be familiar with the following
Kubernetes concepts.
* [Pods](/docs/user-guide/pods/single-container/)
@@ -34,16 +34,16 @@ Kubernetes concepts.
* [kubectl CLI](/docs/user-guide/kubectl)
You will require a cluster with at least four nodes, and each node will require
at least 2 CPUs and 4 GiB of memory. In this tutorial you will cordon and
drain the cluster's nodes. **This means that all Pods on the cluster's nodes
will be terminated and evicted, and the nodes will, temporarily, become
unschedulable.** You should use a dedicated cluster for this tutorial, or you
should ensure that the disruption you cause will not interfere with other
at least 2 CPUs and 4 GiB of memory. In this tutorial you will cordon and
drain the cluster's nodes. **This means that all Pods on the cluster's nodes
will be terminated and evicted, and the nodes will, temporarily, become
unschedulable.** You should use a dedicated cluster for this tutorial, or you
should ensure that the disruption you cause will not interfere with other
tenants.
This tutorial assumes that your cluster is configured to dynamically provision
This tutorial assumes that your cluster is configured to dynamically provision
PersistentVolumes. If your cluster is not configured to do so, you
will have to manually provision three 20 GiB volumes prior to starting this
will have to manually provision three 20 GiB volumes prior to starting this
tutorial.
{% endcapture %}
@@ -60,51 +60,51 @@ After this tutorial, you will know the following.
#### ZooKeeper Basics
[Apache ZooKeeper](https://zookeeper.apache.org/doc/current/) is a
[Apache ZooKeeper](https://zookeeper.apache.org/doc/current/) is a
distributed, open-source coordination service for distributed applications.
ZooKeeper allows you to read, write, and observe updates to data. Data are
organized in a file system like hierarchy and replicated to all ZooKeeper
servers in the ensemble (a set of ZooKeeper servers). All operations on data
are atomic and sequentially consistent. ZooKeeper ensures this by using the
[Zab](https://pdfs.semanticscholar.org/b02c/6b00bd5dbdbd951fddb00b906c82fa80f0b3.pdf)
ZooKeeper allows you to read, write, and observe updates to data. Data are
organized in a file system like hierarchy and replicated to all ZooKeeper
servers in the ensemble (a set of ZooKeeper servers). All operations on data
are atomic and sequentially consistent. ZooKeeper ensures this by using the
[Zab](https://pdfs.semanticscholar.org/b02c/6b00bd5dbdbd951fddb00b906c82fa80f0b3.pdf)
consensus protocol to replicate a state machine across all servers in the ensemble.
The ensemble uses the Zab protocol to elect a leader, and
data can not be written until a leader is elected. Once a leader is
elected, the ensemble uses Zab to ensure that all writes are replicated to a
data can not be written until a leader is elected. Once a leader is
elected, the ensemble uses Zab to ensure that all writes are replicated to a
quorum before they are acknowledged and made visible to clients. Without respect
to weighted quorums, a quorum is a majority component of the ensemble containing
the current leader. For instance, if the ensemble has three servers, a component
that contains the leader and one other server constitutes a quorum. If the
to weighted quorums, a quorum is a majority component of the ensemble containing
the current leader. For instance, if the ensemble has three servers, a component
that contains the leader and one other server constitutes a quorum. If the
ensemble can not achieve a quorum, data can not be written.
ZooKeeper servers keep their entire state machine in memory, but every mutation
is written to a durable WAL (Write Ahead Log) on storage media. When a server
crashes, it can recover its previous state by replaying the WAL. In order to
prevent the WAL from growing without bound, ZooKeeper servers will periodically
snapshot their in memory state to storage media. These snapshots can be loaded
directly into memory, and all WAL entries that preceded the snapshot may be
ZooKeeper servers keep their entire state machine in memory, but every mutation
is written to a durable WAL (Write Ahead Log) on storage media. When a server
crashes, it can recover its previous state by replaying the WAL. In order to
prevent the WAL from growing without bound, ZooKeeper servers will periodically
snapshot their in memory state to storage media. These snapshots can be loaded
directly into memory, and all WAL entries that preceded the snapshot may be
safely discarded.
### Creating a ZooKeeper Ensemble
The manifest below contains a
[Headless Service](/docs/user-guide/services/#headless-services),
a [ConfigMap](/docs/user-guide/configmap/),
a [PodDisruptionBudget](/docs/admin/disruptions/#specifying-a-poddisruptionbudget),
and a [StatefulSet](/docs/concepts/abstractions/controllers/statefulsets/).
The manifest below contains a
[Headless Service](/docs/user-guide/services/#headless-services),
a [ConfigMap](/docs/user-guide/configmap/),
a [PodDisruptionBudget](/docs/admin/disruptions/#specifying-a-poddisruptionbudget),
and a [StatefulSet](/docs/concepts/abstractions/controllers/statefulsets/).
{% include code.html language="yaml" file="zookeeper.yaml" ghlink="/docs/tutorials/stateful-application/zookeeper.yaml" %}
Open a command terminal, and use
[`kubectl create`](/docs/user-guide/kubectl/kubectl_create/) to create the
Open a command terminal, and use
[`kubectl create`](/docs/user-guide/kubectl/kubectl_create/) to create the
manifest.
```shell
kubectl create -f http://k8s.io/docs/tutorials/stateful-application/zookeeper.yaml
```
This creates the `zk-headless` Headless Service, the `zk-config` ConfigMap,
This creates the `zk-headless` Headless Service, the `zk-config` ConfigMap,
the `zk-budget` PodDisruptionBudget, and the `zk` StatefulSet.
```shell
@@ -142,29 +142,29 @@ zk-2 0/1 Running 0 19s
zk-2 1/1 Running 0 40s
```
The StatefulSet controller creates three Pods, and each Pod has a container with
The StatefulSet controller creates three Pods, and each Pod has a container with
a [ZooKeeper 3.4.9](http://www-us.apache.org/dist/zookeeper/zookeeper-3.4.9/) server.
#### Facilitating Leader Election
As there is no terminating algorithm for electing a leader in an anonymous
network, Zab requires explicit membership configuration in order to perform
leader election. Each server in the ensemble needs to have a unique
As there is no terminating algorithm for electing a leader in an anonymous
network, Zab requires explicit membership configuration in order to perform
leader election. Each server in the ensemble needs to have a unique
identifier, all servers need to know the global set of identifiers, and each
identifier needs to be associated with a network address.
Use [`kubectl exec`](/docs/user-guide/kubectl/kubectl_exec/) to get the hostnames
Use [`kubectl exec`](/docs/user-guide/kubectl/kubectl_exec/) to get the hostnames
of the Pods in the `zk` StatefulSet.
```shell
for i in 0 1 2; do kubectl exec zk-$i -- hostname; done
```
The StatefulSet controller provides each Pod with a unique hostname based on its
ordinal index. The hostnames take the form `<statefulset name>-<ordinal index>`.
As the `replicas` field of the `zk` StatefulSet is set to `3`, the Set's
controller creates three Pods with their hostnames set to `zk-0`, `zk-1`, and
`zk-2`.
The StatefulSet controller provides each Pod with a unique hostname based on its
ordinal index. The hostnames take the form `<statefulset name>-<ordinal index>`.
As the `replicas` field of the `zk` StatefulSet is set to `3`, the Set's
controller creates three Pods with their hostnames set to `zk-0`, `zk-1`, and
`zk-2`.
```shell
zk-0
@@ -172,9 +172,9 @@ zk-1
zk-2
```
The servers in a ZooKeeper ensemble use natural numbers as unique identifiers, and
each server's identifier is stored in a file called `myid` in the server’s
data directory.
The servers in a ZooKeeper ensemble use natural numbers as unique identifiers, and
each server's identifier is stored in a file called `myid` in the server's
data directory.
Examine the contents of the `myid` file for each server.
@@ -182,7 +182,7 @@ Examine the contents of the `myid` file for each server.
for i in 0 1 2; do echo "myid zk-$i";kubectl exec zk-$i -- cat /var/lib/zookeeper/data/myid; done
```
As the identifiers are natural numbers and the ordinal indices are non-negative
As the identifiers are natural numbers and the ordinal indices are non-negative
integers, you can generate an identifier by adding one to the ordinal.
```shell
@@ -200,7 +200,7 @@ Get the FQDN (Fully Qualified Domain Name) of each Pod in the `zk` StatefulSet.
for i in 0 1 2; do kubectl exec zk-$i -- hostname -f; done
```
The `zk-headless` Service creates a domain for all of the Pods,
The `zk-headless` Service creates a domain for all of the Pods,
`zk-headless.default.svc.cluster.local`.
```shell
@@ -209,11 +209,11 @@ zk-1.zk-headless.default.svc.cluster.local
zk-2.zk-headless.default.svc.cluster.local
```
The A records in [Kubernetes DNS](/docs/admin/dns/) resolve the FQDNs to the Pods' IP addresses.
If the Pods are rescheduled, the A records will be updated with the Pods' new IP
The A records in [Kubernetes DNS](/docs/admin/dns/) resolve the FQDNs to the Pods' IP addresses.
If the Pods are rescheduled, the A records will be updated with the Pods' new IP
addresses, but the A record's names will not change.
ZooKeeper stores its application configuration in a file named `zoo.cfg`. Use
ZooKeeper stores its application configuration in a file named `zoo.cfg`. Use
`kubectl exec` to view the contents of the `zoo.cfg` file in the `zk-0` Pod.
```
@@ -222,8 +222,8 @@ kubectl exec zk-0 -- cat /opt/zookeeper/conf/zoo.cfg
For the `server.1`, `server.2`, and `server.3` properties at the bottom of
the file, the `1`, `2`, and `3` correspond to the identifiers in the
ZooKeeper servers' `myid` files. They are set to the FQDNs for the Pods in
the `zk` StatefulSet.
ZooKeeper servers' `myid` files. They are set to the FQDNs for the Pods in
the `zk` StatefulSet.
```shell
clientPort=2181
@@ -244,16 +244,16 @@ server.3=zk-2.zk-headless.default.svc.cluster.local:2888:3888
#### Achieving Consensus
Consensus protocols require that the identifiers of each participant be
unique. No two participants in the Zab protocol should claim the same unique
identifier. This is necessary to allow the processes in the system to agree on
which processes have committed which data. If two Pods were launched with the
Consensus protocols require that the identifiers of each participant be
unique. No two participants in the Zab protocol should claim the same unique
identifier. This is necessary to allow the processes in the system to agree on
which processes have committed which data. If two Pods were launched with the
same ordinal, two ZooKeeper servers would both identify themselves as the same
server.
When you created the `zk` StatefulSet, the StatefulSet's controller created
each Pod sequentially, in the order defined by the Pods' ordinal indices, and it
waited for each Pod to be Running and Ready before creating the next Pod.
When you created the `zk` StatefulSet, the StatefulSet's controller created
each Pod sequentially, in the order defined by the Pods' ordinal indices, and it
waited for each Pod to be Running and Ready before creating the next Pod.
```shell
kubectl get pods -w -l app=zk
@@ -277,7 +277,7 @@ zk-2 1/1 Running 0 40s
The A records for each Pod are only entered when the Pod becomes Ready. Therefore,
the FQDNs of the ZooKeeper servers will only resolve to a single endpoint, and that
endpoint will be the unique ZooKeeper server claiming the identity configured
endpoint will be the unique ZooKeeper server claiming the identity configured
in its `myid` file.
```shell
@@ -286,7 +286,7 @@ zk-1.zk-headless.default.svc.cluster.local
zk-2.zk-headless.default.svc.cluster.local
```
This ensures that the `servers` properties in the ZooKeepers' `zoo.cfg` files
This ensures that the `servers` properties in the ZooKeepers' `zoo.cfg` files
represents a correctly configured ensemble.
```shell
@@ -295,16 +295,16 @@ server.2=zk-1.zk-headless.default.svc.cluster.local:2888:3888
server.3=zk-2.zk-headless.default.svc.cluster.local:2888:3888
```
When the servers use the Zab protocol to attempt to commit a value, they will
either achieve consensus and commit the value (if leader election has succeeded
and at least two of the Pods are Running and Ready), or they will fail to do so
(if either of the aforementioned conditions are not met). No state will arise
When the servers use the Zab protocol to attempt to commit a value, they will
either achieve consensus and commit the value (if leader election has succeeded
and at least two of the Pods are Running and Ready), or they will fail to do so
(if either of the aforementioned conditions are not met). No state will arise
where one server acknowledges a write on behalf of another.
#### Sanity Testing the Ensemble
The most basic sanity test is to write some data to one ZooKeeper server and
to read the data from another.
The most basic sanity test is to write some data to one ZooKeeper server and
to read the data from another.
Use the `zkCli.sh` script to write `world` to the path `/hello` on the `zk-0` Pod.
@@ -327,7 +327,7 @@ Get the data from the `zk-1` Pod.
kubectl exec zk-1 zkCli.sh get /hello
```
The data that you created on `zk-0` is available on all of the servers in the
The data that you created on `zk-0` is available on all of the servers in the
ensemble.
```shell
@@ -351,12 +351,12 @@ numChildren = 0
#### Providing Durable Storage
As mentioned in the [ZooKeeper Basics](#zookeeper-basics) section,
ZooKeeper commits all entries to a durable WAL, and periodically writes snapshots
in memory state, to storage media. Using WALs to provide durability is a common
ZooKeeper commits all entries to a durable WAL, and periodically writes snapshots
in memory state, to storage media. Using WALs to provide durability is a common
technique for applications that use consensus protocols to achieve a replicated
state machine and for storage applications in general.
Use [`kubectl delete`](/docs/user-guide/kubectl/kubectl_delete/) to delete the
Use [`kubectl delete`](/docs/user-guide/kubectl/kubectl_delete/) to delete the
`zk` StatefulSet.
```shell
@@ -392,7 +392,7 @@ Reapply the manifest in `zookeeper.yaml`.
kubectl apply -f http://k8s.io/docs/tutorials/stateful-application/zookeeper.yaml
```
The `zk` StatefulSet will be created, but, as they already exist, the other API
The `zk` StatefulSet will be created, but, as they already exist, the other API
Objects in the manifest will not be modified.
```shell
@@ -429,14 +429,14 @@ zk-2 0/1 Running 0 19s
zk-2 1/1 Running 0 40s
```
Get the value you entered during the [sanity test](#sanity-testing-the-ensemble),
Get the value you entered during the [sanity test](#sanity-testing-the-ensemble),
from the `zk-2` Pod.
```shell
kubectl exec zk-2 zkCli.sh get /hello
```
Even though all of the Pods in the `zk` StatefulSet have been terminated and
Even though all of the Pods in the `zk` StatefulSet have been terminated and
recreated, the ensemble still serves the original value.
```shell
@@ -457,8 +457,8 @@ dataLength = 5
numChildren = 0
```
The `volumeClaimTemplates` field, of the `zk` StatefulSet's `spec`, specifies a
PersistentVolume that will be provisioned for each Pod.
The `volumeClaimTemplates` field, of the `zk` StatefulSet's `spec`, specifies a
PersistentVolume that will be provisioned for each Pod.
```yaml
volumeClaimTemplates:
@@ -474,8 +474,8 @@ volumeClaimTemplates:
```
The StatefulSet controller generates a PersistentVolumeClaim for each Pod in
the StatefulSet.
The StatefulSet controller generates a PersistentVolumeClaim for each Pod in
the StatefulSet.
Get the StatefulSet's PersistentVolumeClaims.
@@ -483,7 +483,7 @@ Get the StatefulSet's PersistentVolumeClaims.
kubectl get pvc -l app=zk
```
When the StatefulSet recreated its Pods, the Pods' PersistentVolumes were
When the StatefulSet recreated its Pods, the Pods' PersistentVolumes were
remounted.
```shell
@@ -502,19 +502,19 @@ volumeMounts:
mountPath: /var/lib/zookeeper
```
When a Pod in the `zk` StatefulSet is (re)scheduled, it will always have the
same PersistentVolume mounted to the ZooKeeper server's data directory.
Even when the Pods are rescheduled, all of the writes made to the ZooKeeper
When a Pod in the `zk` StatefulSet is (re)scheduled, it will always have the
same PersistentVolume mounted to the ZooKeeper server's data directory.
Even when the Pods are rescheduled, all of the writes made to the ZooKeeper
servers' WALs, and all of their snapshots, remain durable.
### Ensuring Consistent Configuration
As noted in the [Facilitating Leader Election](#facilitating-leader-election) and
[Achieving Consensus](#achieving-consensus) sections, the servers in a
ZooKeeper ensemble require consistent configuration in order to elect a leader
[Achieving Consensus](#achieving-consensus) sections, the servers in a
ZooKeeper ensemble require consistent configuration in order to elect a leader
and form a quorum. They also require consistent configuration of the Zab protocol
in order for the protocol to work correctly over a network. You can use
ConfigMaps to achieve this.
in order for the protocol to work correctly over a network. You can use
ConfigMaps to achieve this.
Get the `zk-config` ConfigMap.
@@ -532,8 +532,8 @@ data:
tick: "2000"
```
The `env` field of the `zk` StatefulSet's Pod `template` reads the ConfigMap
into environment variables. These variables are injected into the containers
The `env` field of the `zk` StatefulSet's Pod `template` reads the ConfigMap
into environment variables. These variables are injected into the containers
environment.
```yaml
@@ -581,7 +581,7 @@ env:
```
The entry point of the container invokes a bash script, `zkConfig.sh`, prior to
launching the ZooKeeper server process. This bash script generates the
launching the ZooKeeper server process. This bash script generates the
ZooKeeper configuration files from the supplied environment variables.
```yaml
@@ -597,8 +597,8 @@ Examine the environment of all of the Pods in the `zk` StatefulSet.
for i in 0 1 2; do kubectl exec zk-$i env | grep ZK_*;echo""; done
```
All of the variables populated from `zk-config` contain identical values. This
allows the `zkGenConfig.sh` script to create consistent configurations for all
All of the variables populated from `zk-config` contain identical values. This
allows the `zkGenConfig.sh` script to create consistent configurations for all
of the ZooKeeper servers in the ensemble.
```shell
@@ -653,16 +653,16 @@ ZK_LOG_DIR=/var/log/zookeeper
#### Configuring Logging
One of the files generated by the `zkConfigGen.sh` script controls ZooKeeper's logging.
ZooKeeper uses [Log4j](http://logging.apache.org/log4j/2.x/), and, by default,
it uses a time and size based rolling file appender for its logging configuration.
One of the files generated by the `zkConfigGen.sh` script controls ZooKeeper's logging.
ZooKeeper uses [Log4j](http://logging.apache.org/log4j/2.x/), and, by default,
it uses a time and size based rolling file appender for its logging configuration.
Get the logging configuration from one of Pods in the `zk` StatefulSet.
```shell
kubectl exec zk-0 cat /usr/etc/zookeeper/log4j.properties
```
The logging configuration below will cause the ZooKeeper process to write all
The logging configuration below will cause the ZooKeeper process to write all
of its logs to the standard output file stream.
```shell
@@ -675,20 +675,20 @@ log4j.appender.CONSOLE.layout=org.apache.log4j.PatternLayout
log4j.appender.CONSOLE.layout.ConversionPattern=%d{ISO8601} [myid:%X{myid}] - %-5p [%t:%C{1}@%L] - %m%n
```
This is the simplest possible way to safely log inside the container. As the
application's logs are being written to standard out, Kubernetes will handle
log rotation for you. Kubernetes also implements a sane retention policy that
ensures application logs written to standard out and standard error do not
This is the simplest possible way to safely log inside the container. As the
application's logs are being written to standard out, Kubernetes will handle
log rotation for you. Kubernetes also implements a sane retention policy that
ensures application logs written to standard out and standard error do not
exhaust local storage media.
Use [`kubectl logs`](/docs/user-guide/kubectl/kubectl_logs/) to retrieve the last
Use [`kubectl logs`](/docs/user-guide/kubectl/kubectl_logs/) to retrieve the last
few log lines from one of the Pods.
```shell
kubectl logs zk-0 --tail 20
```
Application logs that are written to standard out or standard error are viewable
Application logs that are written to standard out or standard error are viewable
using `kubectl logs` and from the Kubernetes Dashboard.
```shell
@@ -714,19 +714,19 @@ using `kubectl logs` and from the Kubernetes Dashboard.
2016-12-06 19:34:46,230 [myid:1] - INFO [Thread-1142:NIOServerCnxn@1008] - Closed socket connection for client /127.0.0.1:52768 (no session established for client)
```
Kubernetes also supports more powerful, but more complex, logging integrations
with [Google Cloud Logging](https://github.com/kubernetes/contrib/blob/master/logging/fluentd-sidecar-gcp/README.md)
Kubernetes also supports more powerful, but more complex, logging integrations
with [Google Cloud Logging](https://github.com/kubernetes/contrib/blob/master/logging/fluentd-sidecar-gcp/README.md)
and [ELK](https://github.com/kubernetes/contrib/blob/master/logging/fluentd-sidecar-es/README.md).
For cluster level log shipping and aggregation, you should consider deploying a
[sidecar](http://blog.kubernetes.io/2015/06/the-distributed-system-toolkit-patterns.html)
[sidecar](http://blog.kubernetes.io/2015/06/the-distributed-system-toolkit-patterns.html)
container to rotate and ship your logs.
#### Configuring a Non-Privileged User
The best practices with respect to allowing an application to run as a privileged
user inside of a container are a matter of debate. If your organization requires
that applications be run as a non-privileged user you can use a
[SecurityContext](/docs/user-guide/security-context/) to control the user that
The best practices with respect to allowing an application to run as a privileged
user inside of a container are a matter of debate. If your organization requires
that applications be run as a non-privileged user you can use a
[SecurityContext](/docs/user-guide/security-context/) to control the user that
the entry point runs as.
The `zk` StatefulSet's Pod `template` contains a SecurityContext.
@@ -737,7 +737,7 @@ securityContext:
fsGroup: 1000
```
In the Pods' containers, UID 1000 corresponds to the zookeeper user and GID 1000
In the Pods' containers, UID 1000 corresponds to the zookeeper user and GID 1000
corresponds to the zookeeper group.
Get the ZooKeeper process information from the `zk-0` Pod.
@@ -746,7 +746,7 @@ Get the ZooKeeper process information from the `zk-0` Pod.
kubectl exec zk-0 -- ps -elf
```
As the `runAsUser` field of the `securityContext` object is set to 1000,
As the `runAsUser` field of the `securityContext` object is set to 1000,
instead of running as root, the ZooKeeper process runs as the zookeeper user.
```shell
@@ -755,8 +755,8 @@ F S UID PID PPID C PRI NI ADDR SZ WCHAN STIME TTY TIME CMD
0 S zookeep+ 27 1 0 80 0 - 1155556 - 20:46 ? 00:00:19 /usr/lib/jvm/java-8-openjdk-amd64/bin/java -Dzookeeper.log.dir=/var/log/zookeeper -Dzookeeper.root.logger=INFO,CONSOLE -cp /usr/bin/../build/classes:/usr/bin/../build/lib/*.jar:/usr/bin/../share/zookeeper/zookeeper-3.4.9.jar:/usr/bin/../share/zookeeper/slf4j-log4j12-1.6.1.jar:/usr/bin/../share/zookeeper/slf4j-api-1.6.1.jar:/usr/bin/../share/zookeeper/netty-3.10.5.Final.jar:/usr/bin/../share/zookeeper/log4j-1.2.16.jar:/usr/bin/../share/zookeeper/jline-0.9.94.jar:/usr/bin/../src/java/lib/*.jar:/usr/bin/../etc/zookeeper: -Xmx2G -Xms2G -Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.local.only=false org.apache.zookeeper.server.quorum.QuorumPeerMain /usr/bin/../etc/zookeeper/zoo.cfg
```
By default, when the Pod's PersistentVolume is mounted to the ZooKeeper server's
data directory, it is only accessible by the root user. This configuration
By default, when the Pod's PersistentVolume is mounted to the ZooKeeper server's
data directory, it is only accessible by the root user. This configuration
prevents the ZooKeeper process from writing to its WAL and storing its snapshots.
Get the file permissions of the ZooKeeper data directory on the `zk-0` Pod.
@@ -765,8 +765,8 @@ Get the file permissions of the ZooKeeper data directory on the `zk-0` Pod.
kubectl exec -ti zk-0 -- ls -ld /var/lib/zookeeper/data
```
As the `fsGroup` field of the `securityContext` object is set to 1000,
the ownership of the Pods' PersistentVolumes is set to the zookeeper group,
As the `fsGroup` field of the `securityContext` object is set to 1000,
the ownership of the Pods' PersistentVolumes is set to the zookeeper group,
and the ZooKeeper process is able to successfully read and write its data.
```shell
@@ -775,21 +775,21 @@ drwxr-sr-x 3 zookeeper zookeeper 4096 Dec 5 20:45 /var/lib/zookeeper/data
### Managing the ZooKeeper Process
The [ZooKeeper documentation](https://zookeeper.apache.org/doc/current/zookeeperAdmin.html#sc_supervision)
documentation indicates that "You will want to have a supervisory process that
manages each of your ZooKeeper server processes (JVM)." Utilizing a watchdog
(supervisory process) to restart failed processes in a distributed system is a
common pattern. When deploying an application in Kubernetes, rather than using
an external utility as a supervisory process, you should use Kubernetes as the
The [ZooKeeper documentation](https://zookeeper.apache.org/doc/current/zookeeperAdmin.html#sc_supervision)
documentation indicates that "You will want to have a supervisory process that
manages each of your ZooKeeper server processes (JVM)." Utilizing a watchdog
(supervisory process) to restart failed processes in a distributed system is a
common pattern. When deploying an application in Kubernetes, rather than using
an external utility as a supervisory process, you should use Kubernetes as the
watchdog for your application.
#### Handling Process Failure
#### Handling Process Failure
[Restart Policies](/docs/user-guide/pod-states/#restartpolicy) control how
[Restart Policies](/docs/user-guide/pod-states/#restartpolicy) control how
Kubernetes handles process failures for the entry point of the container in a Pod.
For Pods in a StatefulSet, the only appropriate RestartPolicy is Always, and this
is the default value. For stateful applications you should **never** override
is the default value. For stateful applications you should **never** override
the default policy.
@@ -799,7 +799,7 @@ Examine the process tree for the ZooKeeper server running in the `zk-0` Pod.
kubectl exec zk-0 -- ps -ef
```
The command used as the container's entry point has PID 1, and the
The command used as the container's entry point has PID 1, and the
the ZooKeeper process, a child of the entry point, has PID 23.
@@ -824,8 +824,8 @@ In another terminal, kill the ZooKeeper process in Pod `zk-0`.
```
The death of the ZooKeeper process caused its parent process to terminate. As
the RestartPolicy of the container is Always, the parent process was relaunched.
The death of the ZooKeeper process caused its parent process to terminate. As
the RestartPolicy of the container is Always, the parent process was relaunched.
```shell
@@ -840,19 +840,19 @@ zk-0 1/1 Running 1 29m
```
If your application uses a script (such as zkServer.sh) to launch the process
If your application uses a script (such as zkServer.sh) to launch the process
that implements the application's business logic, the script must terminate with the
child process. This ensures that Kubernetes will restart the application's
container when the process implementing the application's business logic fails.
container when the process implementing the application's business logic fails.
#### Testing for Liveness
Configuring your application to restart failed processes is not sufficient to
keep a distributed system healthy. There are many scenarios where
a system's processes can be both alive and unresponsive, or otherwise
unhealthy. You should use liveness probes in order to notify Kubernetes
Configuring your application to restart failed processes is not sufficient to
keep a distributed system healthy. There are many scenarios where
a system's processes can be both alive and unresponsive, or otherwise
unhealthy. You should use liveness probes in order to notify Kubernetes
that your application's processes are unhealthy and should be restarted.
@@ -869,7 +869,7 @@ The Pod `template` for the `zk` StatefulSet specifies a liveness probe.
```
The probe calls a simple bash script that uses the ZooKeeper `ruok` four letter
The probe calls a simple bash script that uses the ZooKeeper `ruok` four letter
word to test the server's health.
@@ -900,7 +900,7 @@ kubectl exec zk-0 -- rm /opt/zookeeper/bin/zkOk.sh
```
When the liveness probe for the ZooKeeper process fails, Kubernetes will
When the liveness probe for the ZooKeeper process fails, Kubernetes will
automatically restart the process for you, ensuring that unhealthy processes in
the ensemble are restarted.
@@ -921,10 +921,10 @@ zk-0 1/1 Running 1 1h
#### Testing for Readiness
Readiness is not the same as liveness. If a process is alive, it is scheduled
and healthy. If a process is ready, it is able to process input. Liveness is
Readiness is not the same as liveness. If a process is alive, it is scheduled
and healthy. If a process is ready, it is able to process input. Liveness is
a necessary, but not sufficient, condition for readiness. There are many cases,
particularly during initialization and termination, when a process can be
particularly during initialization and termination, when a process can be
alive but not ready.
@@ -932,8 +932,8 @@ If you specify a readiness probe, Kubernetes will ensure that your application's
processes will not receive network traffic until their readiness checks pass.
For a ZooKeeper server, liveness implies readiness. Therefore, the readiness
probe from the `zookeeper.yaml` manifest is identical to the liveness probe.
For a ZooKeeper server, liveness implies readiness. Therefore, the readiness
probe from the `zookeeper.yaml` manifest is identical to the liveness probe.
```yaml
@@ -946,28 +946,28 @@ probe from the `zookeeper.yaml` manifest is identical to the liveness probe.
```
Even though the liveness and readiness probes are identical, it is important
to specify both. This ensures that only healthy servers in the ZooKeeper
Even though the liveness and readiness probes are identical, it is important
to specify both. This ensures that only healthy servers in the ZooKeeper
ensemble receive network traffic.
### Tolerating Node Failure
ZooKeeper needs a quorum of servers in order to successfully commit mutations
to data. For a three server ensemble, two servers must be healthy in order for
writes to succeed. In quorum based systems, members are deployed across failure
domains to ensure availability. In order to avoid an outage, due to the loss of an
individual machine, best practices preclude co-locating multiple instances of the
ZooKeeper needs a quorum of servers in order to successfully commit mutations
to data. For a three server ensemble, two servers must be healthy in order for
writes to succeed. In quorum based systems, members are deployed across failure
domains to ensure availability. In order to avoid an outage, due to the loss of an
individual machine, best practices preclude co-locating multiple instances of the
application on the same machine.
By default, Kubernetes may co-locate Pods in a StatefulSet on the same node.
By default, Kubernetes may co-locate Pods in a StatefulSet on the same node.
For the three server ensemble you created, if two servers reside on the same
node, and that node fails, the clients of your ZooKeeper service will experience
an outage until at least one of the Pods can be rescheduled.
an outage until at least one of the Pods can be rescheduled.
You should always provision additional capacity to allow the processes of critical
systems to be rescheduled in the event of node failures. If you do so, then the
outage will only last until the Kubernetes scheduler reschedules one of the ZooKeeper
systems to be rescheduled in the event of node failures. If you do so, then the
outage will only last until the Kubernetes scheduler reschedules one of the ZooKeeper
servers. However, if you want your service to tolerate node failures with no downtime,
you should use a `PodAntiAffinity` annotation.
@@ -985,7 +985,7 @@ kubernetes-minion-group-a5aq
kubernetes-minion-group-2g2d
```
This is because the Pods in the `zk` StatefulSet contain a
This is because the Pods in the `zk` StatefulSet contain a
[PodAntiAffinity](/docs/user-guide/node-selection/) annotation.
```yaml
@@ -1006,11 +1006,11 @@ scheduler.alpha.kubernetes.io/affinity: >
}
```
The `requiredDuringSchedulingRequiredDuringExecution` field tells the
The `requiredDuringSchedulingRequiredDuringExecution` field tells the
Kubernetes Scheduler that it should never co-locate two Pods from the `zk-headless`
Service in the domain defined by the `topologyKey`. The `topologyKey`
`kubernetes.io/hostname` indicates that the domain is an individual node. Using
different rules, labels, and selectors, you can extend this technique to spread
`kubernetes.io/hostname` indicates that the domain is an individual node. Using
different rules, labels, and selectors, you can extend this technique to spread
your ensemble across physical, network, and power failure domains.
### Surviving Maintenance
@@ -1018,8 +1018,8 @@ your ensemble across physical, network, and power failure domains.
**In this section you will cordon and drain nodes. If you are using this tutorial
on a shared cluster, be sure that this will not adversely affect other tenants.**
The previous section showed you how to spread your Pods across nodes to survive
unplanned node failures, but you also need to plan for temporary node failures
The previous section showed you how to spread your Pods across nodes to survive
unplanned node failures, but you also need to plan for temporary node failures
that occur due to planned maintenance.
Get the nodes in your cluster.
@@ -1028,7 +1028,7 @@ Get the nodes in your cluster.
kubectl get nodes
```
Use [`kubectl cordon`](/docs/user-guide/kubectl/kubectl_cordon/) to
Use [`kubectl cordon`](/docs/user-guide/kubectl/kubectl_cordon/) to
cordon all but four of the nodes in your cluster.
```shell{% raw %}
@@ -1041,8 +1041,8 @@ Get the `zk-budget` PodDisruptionBudget.
kubectl get poddisruptionbudget zk-budget
```
The `min-available` field indicates to Kubernetes that at least two Pods from
`zk` StatefulSet must be available at any time.
The `min-available` field indicates to Kubernetes that at least two Pods from
`zk` StatefulSet must be available at any time.
```yaml
NAME MIN-AVAILABLE ALLOWED-DISRUPTIONS AGE
@@ -1065,7 +1065,7 @@ kubernetes-minion-group-ixsl
kubernetes-minion-group-i4c4
{% endraw %}```
Use [`kubectl drain`](/docs/user-guide/kubectl/kubectl_drain/) to cordon and
Use [`kubectl drain`](/docs/user-guide/kubectl/kubectl_drain/) to cordon and
drain the node on which the `zk-0` Pod is scheduled.
```shell {% raw %}
@@ -1075,7 +1075,7 @@ pod "zk-0" deleted
node "kubernetes-minion-group-pb41" drained
{% endraw %}```
As there are four nodes in your cluster, `kubectl drain`, succeeds and the
As there are four nodes in your cluster, `kubectl drain`, succeeds and the
`zk-0` is rescheduled to another node.
```
@@ -1095,7 +1095,7 @@ zk-0 0/1 Running 0 51s
zk-0 1/1 Running 0 1m
```
Keep watching the StatefulSet's Pods in the first terminal and drain the node on which
Keep watching the StatefulSet's Pods in the first terminal and drain the node on which
`zk-1` is scheduled.
```shell{% raw %}
@@ -1105,8 +1105,8 @@ pod "zk-1" deleted
node "kubernetes-minion-group-ixsl" drained
{% endraw %}```
The `zk-1` Pod can not be scheduled. As the `zk` StatefulSet contains a
`PodAntiAffinity` annotation preventing co-location of the Pods, and as only
The `zk-1` Pod can not be scheduled. As the `zk` StatefulSet contains a
`PodAntiAffinity` annotation preventing co-location of the Pods, and as only
two nodes are schedulable, the Pod will remain in a Pending state.
```shell
@@ -1133,7 +1133,7 @@ zk-1 0/1 Pending 0 0s
zk-1 0/1 Pending 0 0s
```
Continue to watch the Pods of the stateful set, and drain the node on which
Continue to watch the Pods of the stateful set, and drain the node on which
`zk-2` is scheduled.
```shell{% raw %}
@@ -1145,9 +1145,9 @@ There are pending pods when an error occurred: Cannot evict pod as it would viol
pod/zk-2
{% endraw %}```
Use `CRTL-C` to terminate to kubectl.
Use `CRTL-C` to terminate to kubectl.
You can not drain the third node because evicting `zk-2` would violate `zk-budget`. However,
You can not drain the third node because evicting `zk-2` would violate `zk-budget`. However,
the node will remain cordoned.
Use `zkCli.sh` to retrieve the value you entered during the sanity test from `zk-0`.
@@ -1232,9 +1232,9 @@ node "kubernetes-minion-group-ixsl" uncordoned
```
You can use `kubectl drain` in conjunction with PodDisruptionBudgets to ensure that your service
remains available during maintenance. If drain is used to cordon nodes and evict pods prior to
taking the node offline for maintenance, services that express a disruption budget will have that
budget respected. You should always allocate additional capacity for critical services so that
remains available during maintenance. If drain is used to cordon nodes and evict pods prior to
taking the node offline for maintenance, services that express a disruption budget will have that
budget respected. You should always allocate additional capacity for critical services so that
their Pods can be immediately rescheduled.
{% endcapture %}
@@ -1242,8 +1242,8 @@ their Pods can be immediately rescheduled.
{% capture cleanup %}
* Use `kubectl uncordon` to uncordon all the nodes in your cluster.
* You will need to delete the persistent storage media for the PersistentVolumes
used in this tutorial. Follow the necessary steps, based on your environment,
storage configuration, and provisioning method, to ensure that all storage is
used in this tutorial. Follow the necessary steps, based on your environment,
storage configuration, and provisioning method, to ensure that all storage is
reclaimed.
{% endcapture %}
{% include templates/tutorial.md %}
docs/user-guide/configuring-containers.md
+1 -1
View File
@@ -75,7 +75,7 @@ apiVersion: v1
kind: Pod
metadata:
name: hello-world
spec: # specification of the pod’s contents
spec: # specification of the pod's contents
restartPolicy: Never
containers:
- name: hello
docs/user-guide/managing-deployments.md
+20 -20
View File
@@ -85,8 +85,8 @@ NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE
my-nginx-svc 10.0.0.208 80/TCP 0s
```
With the above commands, we first create resources under docs/user-guide/nginx/ and print the resources created with `-o name` output format
(print each resource as resource/name). Then we `grep` only the "service", and then print it with `kubectl get`.
With the above commands, we first create resources under docs/user-guide/nginx/ and print the resources created with `-o name` output format
(print each resource as resource/name). Then we `grep` only the "service", and then print it with `kubectl get`.
If you happen to organize your resources across several subdirectories within a particular directory, you can recursively perform the operations on the subdirectories also, by specifying `--recursive` or `-R` alongside the `--filename,-f` flag.
@@ -102,7 +102,7 @@ project/k8s/development
└── my-pvc.yaml
```
By default, performing a bulk operation on `project/k8s/development` will stop at the first level of the directory, not processing any subdirectories. If we tried to create the resources in this directory using the following command, we'd encounter an error:
By default, performing a bulk operation on `project/k8s/development` will stop at the first level of the directory, not processing any subdirectories. If we tried to create the resources in this directory using the following command, we'd encounter an error:
```shell
$ kubectl create -f project/k8s/development
@@ -131,7 +131,7 @@ deployment "my-deployment" created
persistentvolumeclaim "my-pvc" created
```
If you're interested in learning more about `kubectl`, go ahead and read [kubectl Overview](/docs/user-guide/kubectl-overview).
If you're interested in learning more about `kubectl`, go ahead and read [kubectl Overview](/docs/user-guide/kubectl-overview).
## Using labels effectively
@@ -185,9 +185,9 @@ guestbook-redis-slave-qgazl 1/1 Running 0 3m
## Canary deployments
Another scenario where multiple labels are needed is to distinguish deployments of different releases or configurations of the same component. It is common practice to deploy a *canary* of a new application release (specified via image tag in the pod template) side by side with the previous release so that the new release can receive live production traffic before fully rolling it out.
Another scenario where multiple labels are needed is to distinguish deployments of different releases or configurations of the same component. It is common practice to deploy a *canary* of a new application release (specified via image tag in the pod template) side by side with the previous release so that the new release can receive live production traffic before fully rolling it out.
For instance, you can use a `track` label to differentiate different releases.
For instance, you can use a `track` label to differentiate different releases.
The primary, stable release would have a `track` label with value as `stable`:
@@ -227,13 +227,13 @@ The frontend service would span both sets of replicas by selecting the common su
```
You can tweak the number of replicas of the stable and canary releases to determine the ratio of each release that will receive live production traffic (in this case, 3:1).
Once you're confident, you can update the stable track to the new application release and remove the canary one.
Once you're confident, you can update the stable track to the new application release and remove the canary one.
For a more concrete example, check the [tutorial of deploying Ghost](https://github.com/kelseyhightower/talks/tree/master/kubecon-eu-2016/demo#deploy-a-canary).
## Updating labels
Sometimes existing pods and other resources need to be relabeled before creating new resources. This can be done with `kubectl label`.
Sometimes existing pods and other resources need to be relabeled before creating new resources. This can be done with `kubectl label`.
For example, if you want to label all your nginx pods as frontend tier, simply run:
```shell
@@ -243,8 +243,8 @@ pod "my-nginx-2035384211-u2c7e" labeled
pod "my-nginx-2035384211-u3t6x" labeled
```
This first filters all pods with the label "app=nginx", and then labels them with the "tier=fe".
To see the pods you just labeled, run:
This first filters all pods with the label "app=nginx", and then labels them with the "tier=fe".
To see the pods you just labeled, run:
```shell
$ kubectl get pods -l app=nginx -L tier
@@ -284,7 +284,7 @@ $ kubectl scale deployment/my-nginx --replicas=1
deployment "my-nginx" scaled
```
Now you only have one pod managed by the deployment.
Now you only have one pod managed by the deployment.
```shell
$ kubectl get pods -l app=nginx
@@ -294,25 +294,25 @@ my-nginx-2035384211-j5fhi 1/1 Running 0 30m
To have the system automatically choose the number of nginx replicas as needed, ranging from 1 to 3, do:
```shell
```shell
$ kubectl autoscale deployment/my-nginx --min=1 --max=3
deployment "my-nginx" autoscaled
```
Now your nginx replicas will be scaled up and down as needed, automatically.
Now your nginx replicas will be scaled up and down as needed, automatically.
For more information, please see [kubectl scale](/docs/user-guide/kubectl/kubectl_scale/), [kubectl autoscale](/docs/user-guide/kubectl/kubectl_autoscale/) and [horizontal pod autoscaler](/docs/user-guide/horizontal-pod-autoscaler/) document.
## In-place updates of resources
Sometimes it's necessary to make narrow, non-disruptive updates to resources you've created.
Sometimes it's necessary to make narrow, non-disruptive updates to resources you've created.
### kubectl apply
It is suggested to maintain a set of configuration files in source control (see [configuration as code](http://martinfowler.com/bliki/InfrastructureAsCode.html)),
so that they can be maintained and versioned along with the code for the resources they configure.
Then, you can use [`kubectl apply`](/docs/user-guide/kubectl/kubectl_apply/) to push your configuration changes to the cluster.
Then, you can use [`kubectl apply`](/docs/user-guide/kubectl/kubectl_apply/) to push your configuration changes to the cluster.
This command will compare the version of the configuration that you're pushing with the previous version and apply the changes you've made, without overwriting any automated changes to properties you haven't specified.
@@ -357,7 +357,7 @@ For more information, please see [kubectl edit](/docs/user-guide/kubectl/kubectl
Suppose you want to fix a typo of the container's image of a Deployment. One way to do that is with `kubectl patch`:
```shell
# Suppose you have a Deployment with a container named "nginx" and its image "nignx" (typo),
# Suppose you have a Deployment with a container named "nginx" and its image "nignx" (typo),
# use container name "nginx" as a key to update the image from "nignx" (typo) to "nginx"
$ kubectl get deployment my-nginx -o yaml
```
@@ -396,7 +396,7 @@ spec:
The patch is specified using json.
The system ensures that you don’t clobber changes made by other users or components by confirming that the `resourceVersion` doesn’t differ from the version you edited. If you want to update regardless of other changes, remove the `resourceVersion` field when you edit the resource. However, if you do this, don’t use your original configuration file as the source since additional fields most likely were set in the live state.
The system ensures that you don't clobber changes made by other users or components by confirming that the `resourceVersion` doesn't differ from the version you edited. If you want to update regardless of other changes, remove the `resourceVersion` field when you edit the resource. However, if you do this, don't use your original configuration file as the source since additional fields most likely were set in the live state.
For more information, please see [kubectl patch](/docs/user-guide/kubectl/kubectl_patch/) document.
@@ -414,8 +414,8 @@ deployment "my-nginx" replaced
At some point, you'll eventually need to update your deployed application, typically by specifying a new image or image tag, as in the canary deployment scenario above. `kubectl` supports several update operations, each of which is applicable to different scenarios.
We'll guide you through how to create and update applications with Deployments. If your deployed application is managed by Replication Controllers,
you should read [how to use `kubectl rolling-update`](/docs/user-guide/rolling-updates/) instead.
We'll guide you through how to create and update applications with Deployments. If your deployed application is managed by Replication Controllers,
you should read [how to use `kubectl rolling-update`](/docs/user-guide/rolling-updates/) instead.
Let's say you were running version 1.7.9 of nginx:
@@ -424,7 +424,7 @@ $ kubectl run my-nginx --image=nginx:1.7.9 --replicas=3
deployment "my-nginx" created
```
To update to version 1.9.1, simply change `.spec.template.spec.containers[0].image` from `nginx:1.7.9` to `nginx:1.9.1`, with the kubectl commands we learned above.
To update to version 1.9.1, simply change `.spec.template.spec.containers[0].image` from `nginx:1.7.9` to `nginx:1.9.1`, with the kubectl commands we learned above.
```shell
$ kubectl edit deployment/my-nginx
docs/user-guide/pod-security-policy/index.md
+19 -19
View File
@@ -4,8 +4,8 @@ assignees:
title: Pod Security Policies
---
Objects of type `podsecuritypolicy` govern the ability
to make requests on a pod that affect the `SecurityContext` that will be
Objects of type `podsecuritypolicy` govern the ability
to make requests on a pod that affect the `SecurityContext` that will be
applied to a pod and container.
See [PodSecurityPolicy proposal](https://github.com/kubernetes/kubernetes/blob/{{page.githubbranch}}/docs/proposals/security-context-constraints.md) for more information.
@@ -15,10 +15,10 @@ See [PodSecurityPolicy proposal](https://github.com/kubernetes/kubernetes/blob/{
## What is a Pod Security Policy?
A _Pod Security Policy_ is a cluster-level resource that controls the
A _Pod Security Policy_ is a cluster-level resource that controls the
actions that a pod can perform and what it has the ability to access. The
`PodSecurityPolicy` objects define a set of conditions that a pod must
run with in order to be accepted into the system. They allow an
`PodSecurityPolicy` objects define a set of conditions that a pod must
run with in order to be accepted into the system. They allow an
administrator to control the following:
1. Running of privileged containers.
@@ -26,21 +26,21 @@ administrator to control the following:
1. The SELinux context of the container.
1. The user ID.
1. The use of host namespaces and networking.
1. Allocating an FSGroup that owns the pod’s volumes
1. Allocating an FSGroup that owns the pod's volumes
1. Configuring allowable supplemental groups
1. Requiring the use of a read only root file system
1. Controlling the usage of volume types
_Pod Security Policies_ are comprised of settings and strategies that
control the security features a pod has access to. These settings fall
_Pod Security Policies_ are comprised of settings and strategies that
control the security features a pod has access to. These settings fall
into three categories:
- *Controlled by a boolean*: Fields of this type default to the most
restrictive value.
- *Controlled by an allowable set*: Fields of this type are checked
- *Controlled by a boolean*: Fields of this type default to the most
restrictive value.
- *Controlled by an allowable set*: Fields of this type are checked
against the set to ensure their value is allowed.
- *Controlled by a strategy*: Items that have a strategy to generate a value provide
a mechanism to generate the value and a mechanism to ensure that a
a mechanism to generate the value and a mechanism to ensure that a
specified value falls into the set of allowable values.
@@ -65,22 +65,22 @@ specified.
### SupplementalGroups
- *MustRunAs* - Requires at least one range to be specified. Uses the
- *MustRunAs* - Requires at least one range to be specified. Uses the
minimum value of the first range as the default. Validates against all ranges.
- *RunAsAny* - No default provided. Allows any `*supplementalGroups*` to be
specified.
### FSGroup
- *MustRunAs* - Requires at least one range to be specified. Uses the
minimum value of the first range as the default. Validates against the
- *MustRunAs* - Requires at least one range to be specified. Uses the
minimum value of the first range as the default. Validates against the
first ID in the first range.
- *RunAsAny* - No default provided. Allows any `*fsGroup*` ID to be specified.
### Controlling Volumes
The usage of specific volume types can be controlled by setting the
volumes field of the PSP. The allowable values of this field correspond
The usage of specific volume types can be controlled by setting the
volumes field of the PSP. The allowable values of this field correspond
to the volume sources that are defined when creating a volume:
1. azureFile
@@ -104,7 +104,7 @@ to the volume sources that are defined when creating a volume:
1. configMap
1. \* (allow all volumes)
The recommended minimum set of allowed volumes for new PSPs are
The recommended minimum set of allowed volumes for new PSPs are
configMap, downwardAPI, emptyDir, persistentVolumeClaim, and secret.
## Admission
@@ -150,7 +150,7 @@ podsecuritypolicy "permissive" deleted
## Enabling Pod Security Policies
In order to use Pod Security Policies in your cluster you must ensure the
In order to use Pod Security Policies in your cluster you must ensure the
following
1. You have enabled the api type `extensions/v1beta1/podsecuritypolicy`
docs/user-guide/prereqs.md
+1 -1
View File
@@ -5,7 +5,7 @@ assignees:
title: Installing and Setting up kubectl
---
To deploy and manage applications on Kubernetes, you’ll use the Kubernetes command-line tool, [kubectl](/docs/user-guide/kubectl/). It lets you inspect your cluster resources, create, delete, and update components, and much more. You will use it to look at your new cluster and bring up example apps.
To deploy and manage applications on Kubernetes, you'll use the Kubernetes command-line tool, [kubectl](/docs/user-guide/kubectl/). It lets you inspect your cluster resources, create, delete, and update components, and much more. You will use it to look at your new cluster and bring up example apps.
## Install kubectl Binary Via curl
docs/user-guide/replicasets.md
+1 -1
View File
@@ -35,7 +35,7 @@ their Replica Sets.
## When to use a Replica Set?
A Replica Set ensures that a specified number of pod “replicas” are running at any given
A Replica Set ensures that a specified number of pod "replicas" are running at any given
time. However, a Deployment is a higher-level concept that manages Replica Sets and
provides declarative updates to pods along with a lot of other useful features.
Therefore, we recommend using Deployments instead of directly using Replica Sets, unless
docs/user-guide/replication-controller/index.md
+4 -4
View File
@@ -194,7 +194,7 @@ Ideally, the rolling update controller would take application readiness into acc
The two replication controllers would need to create pods with at least one differentiating label, such as the image tag of the primary container of the pod, since it is typically image updates that motivate rolling updates.
Rolling update is implemented in the client tool
[`kubectl rolling-update`](/docs/user-guide/kubectl/kubectl_rolling-update). Visit [`kubectl rolling-update` tutorial](/docs/user-guide/rolling-updates/) for more concrete examples.
[`kubectl rolling-update`](/docs/user-guide/kubectl/kubectl_rolling-update). Visit [`kubectl rolling-update` tutorial](/docs/user-guide/rolling-updates/) for more concrete examples.
### Multiple release tracks
@@ -233,13 +233,13 @@ object](/docs/api-reference/v1/definitions/#_v1_replicationcontroller).
### ReplicaSet
[`ReplicaSet`](/docs/user-guide/replicasets/) is the next-generation Replication Controller that supports the new [set-based label selector](/docs/user-guide/labels/#set-based-requirement).
It’s mainly used by [`Deployment`](/docs/user-guide/deployments/) as a mechanism to orchestrate pod creation, deletion and updates.
Note that we recommend using Deployments instead of directly using Replica Sets, unless you require custom update orchestration or don’t require updates at all.
It's mainly used by [`Deployment`](/docs/user-guide/deployments/) as a mechanism to orchestrate pod creation, deletion and updates.
Note that we recommend using Deployments instead of directly using Replica Sets, unless you require custom update orchestration or don't require updates at all.
### Deployment (Recommended)
[`Deployment`](/docs/user-guide/deployments/) is a higher-level API object that updates its underlying Replica Sets and their Pods
in a similar fashion as `kubectl rolling-update`. Deployments are recommended if you want this rolling update functionality,
in a similar fashion as `kubectl rolling-update`. Deployments are recommended if you want this rolling update functionality,
because unlike `kubectl rolling-update`, they are declarative, server-side, and have additional features.
### Bare Pods
docs/user-guide/security-context.md
+3 -4
View File
@@ -11,7 +11,7 @@ A security context defines the operating system security settings (uid, gid, cap
There are two levels of security context: pod level security context, and container level security context.
## Pod Level Security Context
Setting security context at the pod applies those settings to all containers in the pod
Setting security context at the pod applies those settings to all containers in the pod
```yaml
apiVersion: v1
@@ -20,7 +20,7 @@ metadata:
name: hello-world
spec:
containers:
# specification of the pod’s containers
# specification of the pod's containers
# ...
securityContext:
fsGroup: 1234
@@ -82,7 +82,6 @@ spec:
```
Please refer to the
[API documentation](/docs/api-reference/v1/definitions/#_v1_securitycontext)
[API documentation](/docs/api-reference/v1/definitions/#_v1_securitycontext)
for a detailed listing and description of all the fields available
within the container security context.
index.html
+8 -8
View File
@@ -80,7 +80,7 @@
<div>
<h4><a href="/docs/user-guide/replication-controller/#what-is-a-replication-controller">Self-healing</a></h4>
<p>Restarts containers that fail, replaces and reschedules containers when nodes die, kills containers
that don’t respond to your user-defined health check, and doesn’t advertise them to clients until they are ready to serve.</p>
that don't respond to your user-defined health check, and doesn't advertise them to clients until they are ready to serve.</p>
</div>
</div>
@@ -100,7 +100,7 @@
<div>
<h4><a href="/docs/user-guide/deployments/#what-is-a-deployment">Automated rollouts and rollbacks</a></h4>
<p>Kubernetes progressively rolls out changes to your application or its configuration, while monitoring
application health to ensure it doesn’t kill all your instances at the same time. If something goes
application health to ensure it doesn't kill all your instances at the same time. If something goes
wrong, Kubernetes will rollback the change for you. Take advantage of a growing ecosystem of deployment solutions.</p>
</div>
<div>
@@ -131,7 +131,7 @@
<h3>Case Studies</h3>
<div id="caseStudiesWrapper">
<div>
<p>Using Kubernetes to reinvent the world’s largest educational company</p>
<p>Using Kubernetes to reinvent the world's largest educational company</p>
<a href="/case-studies/pearson/">Read more</a>
</div>
<div>
@@ -139,11 +139,11 @@
<a href="https://blog.box.com/blog/kubernetes-box-microservices-maximum-velocity/">Read more</a>
</div>
<div>
<p>Inside eBay’s shift to Kubernetes and containers atop OpenStack</p>
<p>Inside eBay's shift to Kubernetes and containers atop OpenStack</p>
<a href="http://www.nextplatform.com/2015/11/12/inside-ebays-shift-to-kubernetes-and-containers-atop-openstack/">Read more</a>
</div>
<div>
<p>Migrating from a homegrown ‘cluster’ to Kubernetes</p>
<p>Migrating from a homegrown 'cluster' to Kubernetes</p>
<a href="https://www.youtube.com/watch?v=6XGUTu3WhBw">Watch the video</a>
</div>
</div>
@@ -154,7 +154,7 @@
<!--&lt;!&ndash;<p>Creating Next Generation Kubernetes Infrastructure at Viacom</p>&ndash;&gt;-->
<!--&lt;!&ndash;</div>&ndash;&gt;-->
<!--<div>-->
<!--<p>Using Kubernetes to reinvent the world’s largest educational company</p>-->
<!--<p>Using Kubernetes to reinvent the world's largest educational company</p>-->
<!--<a href="/case-studies/pearson/">Read more</a>-->
<!--</div>-->
<!--<div>-->
@@ -162,11 +162,11 @@
<!--<a href="https://blog.box.com/blog/kubernetes-box-microservices-maximum-velocity/">Read more</a>-->
<!--</div>-->
<!--<div>-->
<!--<p>Inside eBay’s shift to Kubernetes and containers atop OpenStack</p>-->
<!--<p>Inside eBay's shift to Kubernetes and containers atop OpenStack</p>-->
<!--<a href="http://www.nextplatform.com/2015/11/12/inside-ebays-shift-to-kubernetes-and-containers-atop-openstack/">Read the story</a>-->
<!--</div>-->
<!--<div>-->
<!--<p>Migrating from a homegrown ‘cluster’ to Kubernetes</p>-->
<!--<p>Migrating from a homegrown 'cluster' to Kubernetes</p>-->
<!--<a href="https://www.youtube.com/watch?v=6XGUTu3WhBw">Watch the video</a>-->
<!--</div>-->
<!--</div>-->