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kubeadm and add-ons docs

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This commit is contained in:
Luke Marsden
2016-09-23 14:29:06 +01:00
parent 22a8dbb58e
commit 10884384de
5 changed files with 60 additions and 53 deletions
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_data/guides.yml
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@@ -8,8 +8,8 @@ toc:
section:
- title: What is Kubernetes?
path: /docs/whatisk8s/
- title: Installing Kubernetes Easily on Linux
path: /docs/kubeadm/
- title: Installing Kubernetes on Linux with kubeadm
path: /docs/getting-started-guides/kubeadm/
- title: Hello World on Google Container Engine
path: /docs/hellonode/
- title: Downloading or Building Kubernetes
docs/admin/addons.md
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@@ -3,19 +3,20 @@
## Overview
Add-ons extend the functionality of Kubernetes in a pluggable way.
Add-ons extend the functionality of Kubernetes.
This page lists some of the available add-ons and links to their respective installation instructions.
## Networking and Network Policy
* [Weave Net](https://github.com/weaveworks/weave-kube) is an easy, fast and reliable pod network that carries on working in the face of network partitions, does not depend on a database, and supports Kubernetes policy.
* [Calico](https://github.com/projectcalico/calico-containers/tree/master/docs/cni/kubernetes/manifests/kubeadm) is a simple, scalable, secure L3 networking and network policy provider.
* [Canal](https://github.com/tigera/canal/tree/master/k8s-install/kubeadm) unites Flannel and Calico, providing cloud native networking and network policy.
* [Weave Net](https://github.com/weaveworks/weave-kube) provides networking and network policy, will carry on working on both sides of a network partition, and does not require an external database.
* [Calico](https://github.com/projectcalico/calico-containers/tree/master/docs/cni/kubernetes/manifests/kubeadm) is a secure L3 networking and network policy provider.
* [Canal](https://github.com/tigera/canal/tree/master/k8s-install/kubeadm) unites Flannel and Calico, providing networking and network policy.
## Visualization & Control
* [Weave Scope](https://www.weave.works/documentation/scope-latest-installing/#k8s) is a tool for graphically visualizing your containers, pods, services etc. Use it in conjunction with a [Weave Cloud account](https://cloud.weave.works/) or host the UI yourself.
* [Dashboard](https://github.com/kubernetes/dashboard#kubernetes-dashboard) is a dashboard web interface for Kubernetes.
## Legacy Add-ons
docs/kubeadm.md → docs/getting-started-guides/kubeadm.md
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## Overview
This quickstart will show you how to easily install a secure Kubernetes cluster on machines running Ubuntu 16.04 or CentOS 7, using a tool called `kubeadm` which is part of Kubernetes.
This quickstart shows you how to easily install a secure Kubernetes cluster on machines running Ubuntu 16.04 or CentOS 7.
The installation uses a tool called `kubeadm` which is part of Kubernetes 1.4.
This process should work with local VMs, physical servers and/or cloud servers.
It is intended to be simple enough that you can easily integrate its use into your own automation (Terraform, Chef, Puppet, etc).
This process works with local VMs, physical servers and/or cloud servers.
It is simple enough that you can easily integrate its use into your own automation (Terraform, Chef, Puppet, etc).
**The `kubeadm` tool is currently in alpha but please try it out and give us [feedback](/docs/kubeadm/#feedback)!**
**The `kubeadm` tool is currently in alpha but please try it out and give us [feedback](/docs/getting-started-guides/kubeadm/#feedback)!**
## Prerequisites
1. One or more machines running Ubuntu 16.04 or CentOS 7
1. 2GB or more of RAM per machine
1. A network connection with open ports between the machines (public or private network is fine)
1. 1GB or more of RAM per machine (any less will leave little room for your apps)
1. Full network connectivity between all machines in the cluster (public or private network is fine)
## Objectives
@@ -30,7 +31,7 @@ It is intended to be simple enough that you can easily integrate its use into yo
### (1/4) Installing kubelet and kubeadm on your hosts
You will now install the following packages on all the machines:
You will install the following packages on all the machines:
* `docker`: the container runtime, which Kubernetes depends on.
* `kubelet`: the most core component of Kubernetes.
@@ -44,22 +45,20 @@ For each host in turn:
<!--
# curl https://packages.cloud.google.com/apt/doc/apt-key.gpg | apt-key add -
# cat <<EOF > /etc/apt/sources.list.d/kubernetes.list
deb http://packages.cloud.google.com/apt kubernetes-xenial-unstable main
deb http://packages.cloud.google.com/apt kubernetes-xenial main
EOF
# apt-get update
# apt-get install -y kubelet-kubeadm kubectl
# # OR
# apt-get install -y docker-engine=1.11.2-0~xenial socat
# apt-get install -y kubeadm docker.io§
-->
* SSH into the machine and become `root` if you are not already (for example, run `sudo su -`).
* If the machine is running Ubuntu 16.04, run:
# apt-get install -y docker.io socat
# apt-get install -y docker.io socat apt-transport-https
# curl -s -L \
"https://www.dropbox.com/s/tso6dc7b94ch2sk/debs-5ab576.txz?dl=1" | tar xJv
# dpkg -i debian/bin/unstable/xenial/*.deb
https://storage.googleapis.com/kubeadm/kubernetes-xenial-preview-bundle.txz | tar xJv
# dpkg -i kubernetes-xenial-preview-bundle/*.deb
If the machine is running CentOS 7, run:
@@ -74,24 +73,16 @@ For each host in turn:
# systemctl enable docker && systemctl start docker
# systemctl enable kubelet && systemctl start kubelet
The kubelet will now be restarting every few seconds, as it waits in a crashloop for `kubeadm` to tell it what to do.
Optionally, see also [more details on installing Docker](https://docs.docker.com/engine/installation/#/on-linux).
The kubelet is now restarting every few seconds, as it waits in a crashloop for `kubeadm` to tell it what to do.
### (2/4) Initializing your master
The master is the machine where the "control plane" components run, including `etcd` (the cluster database) and the API server (which the `kubectl` CLI communicates with).
All of these components will run in pods started by `kubelet`.
All of these components run in pods started by `kubelet`.
To initialize the master, pick one of the machines you previously installed `kubelet` and `kubeadm` on, and run:
* If you want to be able to schedule pods on the master, for example if you want a single-machine Kubernetes cluster for development, run:
# kubeadm init --schedule-pods-here
* If you do not want to be able to schedule pods on the master (perhaps for security reasons), run:
# kubeadm init
# kubeadm init
This will download and install the cluster database and "control plane" components.
This may take several minutes.
@@ -119,13 +110,20 @@ The output should look like:
Make a record of the `kubeadm join` command that `kubeadm init` outputs.
You will need this in a moment.
The key included here is secret, keep it safe &mdash; anyone with this key will be able to add authenticated nodes to your cluster.
The key included here is secret, keep it safe &mdash; anyone with this key can add authenticated nodes to your cluster.
The key is used for mutual authentication between the master and the joining nodes.
By default, your cluster will not schedule pods on the master for security reasons.
If you want to be able to schedule pods on the master, for example if you want a single-machine Kubernetes cluster for development, run:
# kubectl taint nodes --all dedicated-
This will remove the "dedicated" taint from all nodes, including the master node, meaning that the scheduler will then be able to schedule pods everywhere.
### (3/4) Joining your nodes
The nodes are where your workloads (containers and pods, etc) will run.
The nodes are where your workloads (containers and pods, etc) run.
If you want to add any new machines as nodes to your cluster, for each machine: SSH to that machine, become root (e.g. `sudo su -`) and run the command that was output by `kubeadm init`.
For example:
@@ -154,31 +152,29 @@ Before you can deploy applications to it, you need to install a pod network.
### (4/4) Installing a pod network
You must install a pod network add-on so that your pods can communicate with each other when they are on different hosts.
**It is necessary to do this before you try to deploy any applications to your cluster.**
Several projects provide Kubernetes pod networks.
You can see a complete list of available network add-ons on the [add-ons page](/docs/admin/addons/).
By way of example, you can install Weave Net by running on the master:
By way of example, you can install [Weave Net](https://github.com/weaveworks/weave-kube) by logging in to the master and running:
# kubectl apply -f https://git.io/weave-kube
daemonset "weave-net" created
**You should install a pod network on the master before you try to deploy any applications to your cluster.**
Once a pod network command has installed, a few seconds later you should see the `kube-dns` pod go into `Running` in the output of `kubectl get pods --all-namespaces`.
If you prefer [Calico](https://github.com/projectcalico/calico-containers/tree/master/docs/cni/kubernetes/manifests/kubeadm) or [Canal](https://github.com/tigera/canal/tree/master/k8s-install/kubeadm), please refer to their respective installation guides.
You should only install one pod network per cluster.
Once a pod network has been installed, you can confirm that it is working by checking that the `kube-dns` pod is `Running` in the output of `kubectl get pods --all-namespaces`.
**This signifies that your cluster is ready.**
You can learn more about other available pod networks on the [add-ons page](/docs/admin/addons/).
### (Optional) Installing a sample application
As an example, you will now install a sample microservices application, a socks shop, to put your cluster through its paces.
As an example, install a sample microservices application, a socks shop, to put your cluster through its paces.
To learn more about the sample microservices app, see the [GitHub README](https://github.com/microservices-demo/microservices-demo).
Here you will install the NodePort version of the Socks Shop, which doesn't depend on Load Balancer integration, since our cluster doesn't have that:
# kubectl apply -f https://raw.githubusercontent.com/lukemarsden/microservices-demo/master/deploy/kubernetes/definitions/wholeWeaveDemo-NodePort.yaml
# git clone https://github.com/microservices-demo/microservices-demo
# kubectl apply -f microservices-demo/deploy/kubernetes/manifests
You can then find out the port that the [NodePort feature of services](/docs/user-guide/services/) allocated for the front-end service by running:
@@ -194,11 +190,11 @@ You can then find out the port that the [NodePort feature of services](/docs/use
Endpoints: <none>
Session Affinity: None
It will take several minutes to download and start all the containers, watch the output of `kubectl get pods` to see when they're all up and running.
It takes several minutes to download and start all the containers, watch the output of `kubectl get pods` to see when they're all up and running.
Then go to the IP address of your cluster's master node in your browser, and specify the given port.
So for example, `http://<master_ip>:<port>`.
In the example above, this was `31869`, but it will be a different port for you.
In the example above, this was `31869`, but it is a different port for you.
If there is a firewall, make sure it exposes this port to the internet before you try to access it.
@@ -215,9 +211,19 @@ See the [list of add-ons](/docs/admin/addons/) to explore other add-ons, includi
## Cleanup
* To uninstall the socks shop, run `kubectl delete -f https://raw.githubusercontent.com/lukemarsden/microservices-demo/master/deploy/kubernetes/definitions/wholeWeaveDemo-NodePort.yaml`.
* To uninstall Kubernetes, simply delete the machines you created for this tutorial.
Or alternatively, uninstall the `kubelet`, `kubeadm` and `kubectl` packages and then manually delete all the Docker container that were created by this process.
* To uninstall the socks shop, run `kubectl delete -f microservices-demo/deploy/kubernetes/manifests` on the master.
* To uninstall Kubernetes, simply delete the machines you created for this tutorial, or run the script below.
<details>
```
systemctl stop kubelet
docker rm -f $(docker ps -q); mount | grep "/var/lib/kubelet/*" | awk '{print $3}' | xargs umount 1>/dev/null 2>/dev/null
rm -rf /var/lib/kubelet /etc/kubernetes /var/lib/etcd /etc/cni
ip link set cbr0 down; ip link del cbr0
ip link set cni0 down; ip link del cni0
systemctl start kubelet
```
</details>
## Feedback
@@ -233,8 +239,8 @@ Please note: `kubeadm` is a work in progress and these limitations will be addre
To easily obtain a cluster which works with LBs and PVs Kubernetes, try [the "hello world" GKE tutorial](/docs/hellonode) or [one of the other cloud-specific installation tutorials](/docs/getting-started-guides/).
Workaround: use the [NodePort feature of services](/docs/user-guide/services/#type-nodeport) to demonstrate exposing the sample application on the internet.
1. The cluster created here will have a single master, with a single `etcd` database running on it.
This means that if the master fails, your cluster will lose its configuration data and will need to be recreated from scratch.
1. The cluster created here has a single master, with a single `etcd` database running on it.
This means that if the master fails, your cluster loses its configuration data and will need to be recreated from scratch.
Adding HA support (multiple `etcd` servers, multiple API servers, etc) to `kubeadm` is still a work-in-progress.
Workaround: regularly [back up etcd](https://coreos.com/etcd/docs/latest/admin_guide.html).
@@ -244,4 +250,4 @@ Please note: `kubeadm` is a work in progress and these limitations will be addre
Workaround: use `docker logs` on the nodes where the containers are running as a workaround.
1. There is not yet an easy way to generate a `kubeconfig` file which can be used to authenticate to the cluster remotely with `kubectl` on, for example, your workstation.
Workaround: copy the kubelet's `kubeconfig` from the master: use `scp root@<master>:/etc/kubernetes/kubelet.conf .` and then e.g. `kubectl --kubeconfig ./kubelet.conf get nodes` from your workstation.
Workaround: copy the kubelet's `kubeconfig` from the master: use `scp root@<master>:/etc/kubernetes/admin.conf .` and then e.g. `kubectl --kubeconfig ./admin.conf get nodes` from your workstation.
docs/index.md
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<a href="/docs/hellonode/" class="button">Get Started on GKE</a>
</div>
<div class="col3rd">
<h3>Installing Kubernetes Easily on Linux</h3>
<h3>Installing Kubernetes on Linux with kubeadm</h3>
<p>This quickstart will show you how to install a secure Kubernetes cluster on any computers running Linux, using a tool called <code>kubeadm</code> which is part of Kubernetes. It'll work with local VMs, physical servers and/or cloud servers, either manually or as part of your own automation. It is currently in alpha but please try it out and give us feedback!</p>
<a href="/docs/kubeadm/" class="button">Install Kubernetes Easily</a>
<a href="/docs/getting-started-guides/kubeadm/" class="button">Install Kubernetes with kubeadm</a>
</div>
<div class="col3rd">
<h3>Guided Tutorial</h3>
CNAME → old.CNAME
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