PLEASE NOTE: This document applies to the HEAD of the source tree
If you are using a released version of Kubernetes, you should
refer to the docs that go with that version.
The latest release of this document can be found
[here](http://releases.k8s.io/release-1.1/docs/getting-started-guides/centos/centos_manual_config.md).
Documentation for other releases can be found at
[releases.k8s.io](http://releases.k8s.io).
--
Getting started on [CentOS](http://centos.org)
----------------------------------------------
**Table of Contents**
- [Prerequisites](#prerequisites)
- [Starting a cluster](#starting-a-cluster)
## Prerequisites
You need two machines with CentOS installed on them.
## Starting a cluster
This is a getting started guide for CentOS. It is a manual configuration so you understand all the underlying packages / services / ports, etc...
This guide will only get ONE node working. Multiple nodes requires a functional [networking configuration](../../admin/networking.md) done outside of kubernetes. Although the additional Kubernetes configuration requirements should be obvious.
The Kubernetes package provides a few services: kube-apiserver, kube-scheduler, kube-controller-manager, kubelet, kube-proxy. These services are managed by systemd and the configuration resides in a central location: /etc/kubernetes. We will break the services up between the hosts. The first host, centos-master, will be the Kubernetes master. This host will run the kube-apiserver, kube-controller-manager, and kube-scheduler. In addition, the master will also run _etcd_. The remaining host, centos-minion will be the node and run kubelet, proxy, cadvisor and docker.
**System Information:**
Hosts:
```
centos-master = 192.168.121.9
centos-minion = 192.168.121.65
```
**Prepare the hosts:**
* Create a virt7-docker-common-release repo on all hosts - centos-{master,minion} with following information.
```
[virt7-docker-common-release]
name=virt7-docker-common-release
baseurl=http://cbs.centos.org/repos/virt7-docker-common-release/x86_64/os/
gpgcheck=0
```
* Install Kubernetes on all hosts - centos-{master,minion}. This will also pull in etcd, docker, and cadvisor.
```sh
yum -y install --enablerepo=virt7-docker-common-release kubernetes
```
* Add master and node to /etc/hosts on all machines (not needed if hostnames already in DNS)
```sh
echo "192.168.121.9 centos-master
192.168.121.65 centos-minion" >> /etc/hosts
```
* Edit /etc/kubernetes/config which will be the same on all hosts to contain:
```sh
# Comma separated list of nodes in the etcd cluster
KUBE_ETCD_SERVERS="--etcd-servers=http://centos-master:4001"
# logging to stderr means we get it in the systemd journal
KUBE_LOGTOSTDERR="--logtostderr=true"
# journal message level, 0 is debug
KUBE_LOG_LEVEL="--v=0"
# Should this cluster be allowed to run privileged docker containers
KUBE_ALLOW_PRIV="--allow-privileged=false"
```
* Disable the firewall on both the master and node, as docker does not play well with other firewall rule managers
```sh
systemctl disable iptables-services firewalld
systemctl stop iptables-services firewalld
```
**Configure the Kubernetes services on the master.**
* Edit /etc/kubernetes/apiserver to appear as such:
```sh
# The address on the local server to listen to.
KUBE_API_ADDRESS="--address=0.0.0.0"
# The port on the local server to listen on.
KUBE_API_PORT="--port=8080"
# How the replication controller and scheduler find the kube-apiserver
KUBE_MASTER="--master=http://centos-master:8080"
# Port kubelets listen on
KUBELET_PORT="--kubelet-port=10250"
# Address range to use for services
KUBE_SERVICE_ADDRESSES="--service-cluster-ip-range=10.254.0.0/16"
# Add your own!
KUBE_API_ARGS=""
```
* Start the appropriate services on master:
```sh
for SERVICES in etcd kube-apiserver kube-controller-manager kube-scheduler; do
systemctl restart $SERVICES
systemctl enable $SERVICES
systemctl status $SERVICES
done
```
**Configure the Kubernetes services on the node.**
***We need to configure the kubelet and start the kubelet and proxy***
* Edit /etc/kubernetes/kubelet to appear as such:
```sh
# The address for the info server to serve on
KUBELET_ADDRESS="--address=0.0.0.0"
# The port for the info server to serve on
KUBELET_PORT="--port=10250"
# You may leave this blank to use the actual hostname
KUBELET_HOSTNAME="--hostname-override=centos-minion"
# Location of the api-server
KUBELET_API_SERVER="--api-servers=http://centos-master:8080"
# Add your own!
KUBELET_ARGS=""
```
* Start the appropriate services on node (centos-minion).
```sh
for SERVICES in kube-proxy kubelet docker; do
systemctl restart $SERVICES
systemctl enable $SERVICES
systemctl status $SERVICES
done
```
*You should be finished!*
* Check to make sure the cluster can see the node (on centos-master)
```console
$ kubectl get nodes
NAME LABELS STATUS
centos-minion Ready
```
**The cluster should be running! Launch a test pod.**
You should have a functional cluster, check out [101](../../../docs/user-guide/walkthrough/README.md)!
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