Docker Cookbook

152 | Chapter 5: Kubernetes

---

net: 
"host"
volumes:
- /var/run/docker.sock:/var/run/docker.sock
command: /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
proxy:
image: gcr.io/google_containers/hyperkube:v0.14.1
net: 
"host"
privileged: true
command: /hyperkube proxy --master=http://127.0.0.1:8080 --v=2
Three containers are started by Compose: one container running 
etcd
, one container
running the Kubernetes proxy service, and one container running the Kubernetes
kubelet. Both the service proxy and the kubelet are running from the same image and
using the same binary that is called through the command option. This binary is
hyperkube
, a very nice utility binary that you can use to start all the components of a
Kubernetes cluster.
The clever part is that the 
master
container calls 
hyperkube
by specifying a configura‐
tion file in 
/etc/kubernetes/manifests
located within the container image. You can
check what is in this manifest by running a new ephemeral container:
$ docker run --rm -it gcr.io/google_containers/hyperkube:v0.14.1 cat /etc/ \
kubernetes/manifests/master.json
{
"apiVersion": "v1beta3",
"kind": "Pod",
"metadata": {"name":"nginx"},
"spec":{
"hostNetwork": true,
"containers":[
{
"name": "controller-manager",
"image": "gcr.io/google_containers/hyperkube:v0.14.1",
"command": [
"/hyperkube",
"controller-manager",
"--master=127.0.0.1:8080",
"--machines=127.0.0.1",
"--sync_nodes=true",
"--v=2"
]
},
{
"name": "apiserver",
"image": "gcr.io/google_containers/hyperkube:v0.14.1",
"command": [
"/hyperkube",
"apiserver",