@@ -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 <ahref="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>
@@ -86,9 +86,9 @@ title: Using kubectl to Create a Deployment
<divclass="row">
<divclass="col-md-8">
<p>For our first Deployment, we’ll use a <ahref="https://nodejs.org">Node.js</a> application packaged in a Docker container. The source code and the Dockerfile are available in the <ahref="https://github.com/kubernetes/kubernetes-bootcamp">GitHub repository</a> for the Kubernetes Bootcamp.</p>
<p>For our first Deployment, we'll use a <ahref="https://nodejs.org">Node.js</a> application packaged in a Docker container. The source code and the Dockerfile are available in the <ahref="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>
<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>
@@ -28,7 +28,7 @@ title: Using a Service to Expose Your App
<divclass="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
<divclass="row">
<divclass="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 <ahref="/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>
@@ -101,7 +101,7 @@ title: Running Multiple Instances of Your App
<divclass="row">
<divclass="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>
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
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 %}
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