154 lines
4.6 KiB
Markdown
154 lines
4.6 KiB
Markdown
---
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---
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* TOC
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{:toc}
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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 node working. Multiple nodes requires a functional [networking configuration](/docs/admin/networking) 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 node and run kubelet, proxy, cadvisor and docker.
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**System Information:**
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Hosts:
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```conf
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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 a virt7-docker-common-release repo on all hosts - centos-{master,minion} with following information.
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```conf
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[virt7-docker-common-release]
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name=virt7-docker-common-release
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baseurl=http://cbs.centos.org/repos/virt7-docker-common-release/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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```shell
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yum -y install --enablerepo=virt7-docker-common-release kubernetes
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```
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* Add master and node to /etc/hosts on all machines (not needed if hostnames already in DNS)
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```shell
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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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```shell
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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:2379"
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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 node, as docker does not play well with other firewall rule managers
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```shell
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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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```shell
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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 kubelets 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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* Start the appropriate services on master:
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```shell
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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 node.**
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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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```shell
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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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# Location of the api-server
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KUBELET_API_SERVER="--api-servers=http://centos-master:8080"
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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 node (centos-minion).
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```shell
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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 $SERVICES
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done
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```
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*You should be finished!*
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* Check to make sure the cluster can see the node (on centos-master)
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```shell
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$ kubectl get nodes
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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](/docs/user-guide/walkthrough/)! |