mirror of https://github.com/k3s-io/k3s
165 lines
5.0 KiB
Markdown
165 lines
5.0 KiB
Markdown
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##Getting started on [CentOS](http://centos.org)
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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](https://github.com/GoogleCloudPlatform/kubernetes/blob/master/docs/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="--portal_net=10.254.0.0/16"
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# Add you 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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