docker.md

Running Kubernetes locally via Docker

Table of Contents

• Overview
• Prerequisites
• Step One: Run etcd
• Step Two: Run the master
• Step Three: Run the service proxy
• Test it out
• Run an application
• Expose it as a service:
• A note on turning down your cluster

Overview

The following instructions show you how to set up a simple, single node Kubernetes cluster using Docker.

Here's a diagram of what the final result will look like:

Prerequisites

1. You need to have docker installed on one machine.

Step One: Run etcd

docker run --net=host -d gcr.io/google_containers/etcd:2.0.9 /usr/local/bin/etcd --addr=127.0.0.1:4001 --bind-addr=0.0.0.0:4001 --data-dir=/var/etcd/data

Step Two: Run the master

docker run --net=host -d -v /var/run/docker.sock:/var/run/docker.sock  gcr.io/google_containers/hyperkube:v0.21.2 /hyperkube kubelet --api_servers=http://localhost:8080 --v=2 --address=0.0.0.0 --enable_server --hostname_override=127.0.0.1 --config=/etc/kubernetes/manifests

This actually runs the kubelet, which in turn runs a pod that contains the other master components.

Step Three: Run the service proxy

Note, this could be combined with master above, but it requires --privileged for iptables manipulation

docker run -d --net=host --privileged gcr.io/google_containers/hyperkube:v0.21.2 /hyperkube proxy --master=http://127.0.0.1:8080 --v=2

Test it out

At this point you should have a running Kubernetes cluster. You can test this by downloading the kubectl binary (OS X) (linux)

Note: On OS/X you will need to set up port forwarding via ssh:

boot2docker ssh -L8080:localhost:8080

List the nodes in your cluster by running::

kubectl get nodes

This should print:

NAME        LABELS    STATUS
127.0.0.1   <none>    Ready

If you are running different Kubernetes clusters, you may need to specify -s http://localhost:8080 to select the local cluster.

Run an application

kubectl -s http://localhost:8080 run-container nginx --image=nginx --port=80

now run docker ps you should see nginx running. You may need to wait a few minutes for the image to get pulled.

Expose it as a service

kubectl expose rc nginx --port=80

This should print:

NAME      LABELS    SELECTOR              IP          PORT(S)
nginx     <none>    run=nginx             <ip-addr>   80/TCP

Hit the webserver:

curl <insert-ip-from-above-here>

Note that you will need run this curl command on your boot2docker VM if you are running on OS X.

A note on turning down your cluster

Many of these containers run under the management of the kubelet binary, which attempts to keep containers running, even if they fail. So, in order to turn down the cluster, you need to first kill the kubelet container, and then any other containers.

You may use docker ps -a | awk '{print $1}' | xargs docker kill, note this removes all containers running under Docker, so use with caution.