179fa8cb61
Put a Prerequisites section in all the hosted gettting-started-guides. Change how title and contents are formatted so they are not automatically included in the ToC. Tweak other section headers to improve ToCs.
176 lines
5.3 KiB
Markdown
176 lines
5.3 KiB
Markdown
Getting started on [CentOS](http://centos.org)
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----------------------------------------------
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**Table of Contents**
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- [Prerequisites](#prerequisites)
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- [Starting a cluster](#starting-a-cluster)
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## Prerequisites
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You need two machines with CentOS installed on them.
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## Starting a cluster
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This is a getting started guide for CentOS. It is a manual configuration so you understand all the underlying packages / services / ports, etc...
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This guide will only get ONE minion working. Multiple minions requires a functional [networking configuration](http://docs.k8s.io/networking.md) done outside of kubernetes. Although the additional kubernetes configuration requirements should be obvious.
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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 minion and run kubelet, proxy, cadvisor and docker.
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**System Information:**
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Hosts:
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```
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centos-master = 192.168.121.9
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centos-minion = 192.168.121.65
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```
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**Prepare the hosts:**
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* Create virt7-testing repo on all hosts - centos-{master,minion} with following information.
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```
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[virt7-testing]
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name=virt7-testing
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baseurl=http://cbs.centos.org/repos/virt7-testing/x86_64/os/
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gpgcheck=0
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```
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* Install kubernetes on all hosts - centos-{master,minion}. This will also pull in etcd, docker, and cadvisor.
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```
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yum -y install --enablerepo=virt7-testing kubernetes
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```
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* Note * Using etcd-0.4.6-7 (This is temperory update in documentation)
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If you do not get etcd-0.4.6-7 installed with virt7-testing repo,
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In the current virt7-testing repo, the etcd package is updated which causes service failure. To avoid this,
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```
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yum erase etcd
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```
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It will uninstall the current available etcd package
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```
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yum install http://cbs.centos.org/kojifiles/packages/etcd/0.4.6/7.el7.centos/x86_64/etcd-0.4.6-7.el7.centos.x86_64.rpm
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yum -y install --enablerepo=virt7-testing kubernetes
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```
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* Add master and minion to /etc/hosts on all machines (not needed if hostnames already in DNS)
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```
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echo "192.168.121.9 centos-master
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192.168.121.65 centos-minion" >> /etc/hosts
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```
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* Edit /etc/kubernetes/config which will be the same on all hosts to contain:
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```
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# Comma separated list of nodes in the etcd cluster
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KUBE_ETCD_SERVERS="--etcd_servers=http://centos-master:4001"
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# logging to stderr means we get it in the systemd journal
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KUBE_LOGTOSTDERR="--logtostderr=true"
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# journal message level, 0 is debug
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KUBE_LOG_LEVEL="--v=0"
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# Should this cluster be allowed to run privileged docker containers
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KUBE_ALLOW_PRIV="--allow_privileged=false"
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```
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* Disable the firewall on both the master and minon, as docker does not play well with other firewall rule managers
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```
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systemctl disable iptables-services firewalld
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systemctl stop iptables-services firewalld
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```
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**Configure the kubernetes services on the master.**
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* Edit /etc/kubernetes/apiserver to appear as such:
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```
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# The address on the local server to listen to.
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KUBE_API_ADDRESS="--address=0.0.0.0"
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# The port on the local server to listen on.
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KUBE_API_PORT="--port=8080"
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# How the replication controller and scheduler find the kube-apiserver
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KUBE_MASTER="--master=http://centos-master:8080"
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# Port minions listen on
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KUBELET_PORT="--kubelet_port=10250"
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# Address range to use for services
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KUBE_SERVICE_ADDRESSES="--service-cluster-ip-range=10.254.0.0/16"
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# Add your own!
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KUBE_API_ARGS=""
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```
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* Edit /etc/kubernetes/controller-manager to appear as such:
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```
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# Comma separated list of minions
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KUBELET_ADDRESSES="--machines=centos-minion"
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```
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* Start the appropriate services on master:
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```
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for SERVICES in etcd kube-apiserver kube-controller-manager kube-scheduler; do
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systemctl restart $SERVICES
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systemctl enable $SERVICES
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systemctl status $SERVICES
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done
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```
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**Configure the kubernetes services on the minion.**
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***We need to configure the kubelet and start the kubelet and proxy***
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* Edit /etc/kubernetes/kubelet to appear as such:
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```
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# The address for the info server to serve on
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KUBELET_ADDRESS="--address=0.0.0.0"
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# The port for the info server to serve on
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KUBELET_PORT="--port=10250"
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# You may leave this blank to use the actual hostname
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KUBELET_HOSTNAME="--hostname_override=centos-minion"
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# Add your own!
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KUBELET_ARGS=""
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```
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* Start the appropriate services on minion (centos-minion).
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```
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for SERVICES in kube-proxy kubelet docker; do
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systemctl restart $SERVICES
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systemctl enable $SERVICES
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systemctl status $SERVICES
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done
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```
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*You should be finished!*
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* Check to make sure the cluster can see the minion (on centos-master)
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```
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kubectl get minions
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NAME LABELS STATUS
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centos-minion <none> Ready
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```
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**The cluster should be running! Launch a test pod.**
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You should have a functional cluster, check out [101](https://github.com/GoogleCloudPlatform/kubernetes/blob/master/examples/walkthrough/README.md)!
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[]()
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