k8s 入门系列之集群安装篇

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Kubernetes集群安装部署

•Kubernetes集群组件:
　　- etcd 一个高可用的K/V键值对存储和服务发现系统
　　- flannel 实现夸主机的容器网络的通信
　　- kube-apiserver 提供kubernetes集群的API调用
　　- kube-controller-manager 确保集群服务
　　- kube-scheduler 调度容器，分配到Node
　　- kubelet 在Node节点上按照配置文件中定义的容器规格启动容器
　　- kube-proxy 提供网络代理服务

•集群示意图
　　Kubernetes工作模式server-client，Kubenetes Master提供集中化管理Minions。部署1台Kubernetes Master节点和4台Minion节点，
　示意图如下:

•先决条件

如下操作在所有机器执行

1.确保系统已经安装epel-release源

# yum -y install epel-release

2.关闭防火墙服务，避免与docker容器的防火墙规则冲突。

# systemctl stop firewalld
# systemctl disable firewalld

•安装配置Kubernetes Master
如下操作在master上执行
1.使用yum安装etcd和kubernetes-master

# yum -y install etcd kubernetes-master

2.编辑/etc/etcd/etcd.conf文件

ETCD_NAME=default
ETCD_DATA_DIR="/var/lib/etcd/default.etcd"
ETCD_LISTEN_CLIENT_URLS="http://0.0.0.0:2379"
ETCD_ADVERTISE_CLIENT_URLS="http://localhost:2379"

3.编辑/etc/kubernetes/apiserver文件

KUBE_API_ADDRESS="--insecure-bind-address=0.0.0.0"
KUBE_API_PORT="--port=8080"
KUBELET_PORT="--kubelet-port=10250"
KUBE_ETCD_SERVERS="--etcd-servers=http://127.0.0.1:2379"
KUBE_SERVICE_ADDRESSES="--service-cluster-ip-range=10.254.0.0/16"
KUBE_ADMISSION_CONTROL="--admission-control=NamespaceLifecycle,NamespaceExists,LimitRanger,SecurityContextDeny,ResourceQuota"
KUBE_API_ARGS=""

4.启动etcd、kube-apiserver、kube-controller-manager、kube-scheduler等服务，并设置开机启动。

# for SERVICES in etcd kube-apiserver kube-controller-manager kube-scheduler; do systemctl restart $SERVICES;systemctl enable $SERVICES;systemctl status $SERVICES ; done

5.在etcd中定义flannel网络

# etcdctl mk /atomic.io/network/config '{"Network":"172.17.0.0/16"}'

•安装配置Kubernetes Node
如下操作在node1、node2、node3、node4上执行
1.使用yum安装flannel和kubernetes-node

# yum -y install flannel kubernetes-node

2.为flannel网络指定etcd服务，修改/etc/sysconfig/flanneld文件

FLANNEL_ETCD="http://192.168.30.20:2379"
FLANNEL_ETCD_KEY="/atomic.io/network"

3.修改/etc/kubernetes/config文件

KUBE_LOGTOSTDERR="--logtostderr=true"
KUBE_LOG_LEVEL="--v=0"
KUBE_ALLOW_PRIV="--allow-privileged=false"
KUBE_MASTER="--master=http://192.168.30.20:8080"

4.按照如下内容修改对应node的配置文件/etc/kubernetes/kubelet

node1:

KUBELET_ADDRESS="--address=0.0.0.0"
KUBELET_PORT="--port=10250"
KUBELET_HOSTNAME="--hostname-override=192.168.30.21" #修改成对应Node的IP
KUBELET_API_SERVER="--api-servers=http://192.168.30.20:8080" #指定Master节点的API Server
KUBELET_POD_INFRA_CONTAINER="--pod-infra-container-image=registry.access.redhat.com/rhel7/pod-infrastructure:latest"
KUBELET_ARGS=""

node2:

KUBELET_ADDRESS="--address=0.0.0.0"
KUBELET_PORT="--port=10250"
KUBELET_HOSTNAME="--hostname-override=192.168.30.22" 
KUBELET_API_SERVER="--api-servers=http://192.168.30.20:8080"
KUBELET_POD_INFRA_CONTAINER="--pod-infra-container-image=registry.access.redhat.com/rhel7/pod-infrastructure:latest"
KUBELET_ARGS=""

node3:

KUBELET_ADDRESS="--address=0.0.0.0"
KUBELET_PORT="--port=10250"
KUBELET_HOSTNAME="--hostname-override=192.168.30.23"
KUBELET_API_SERVER="--api-servers=http://192.168.30.20:8080"
KUBELET_POD_INFRA_CONTAINER="--pod-infra-container-image=registry.access.redhat.com/rhel7/pod-infrastructure:latest"
KUBELET_ARGS=""

node4:

KUBELET_ADDRESS="--address=0.0.0.0"
KUBELET_PORT="--port=10250"
KUBELET_HOSTNAME="--hostname-override=192.168.30.24"
KUBELET_API_SERVER="--api-servers=http://192.168.30.20:8080"
KUBELET_POD_INFRA_CONTAINER="--pod-infra-container-image=registry.access.redhat.com/rhel7/pod-infrastructure:latest"
KUBELET_ARGS=""

5.在所有Node节点上启动kube-proxy,kubelet,docker,flanneld等服务，并设置开机启动。

# for SERVICES in kube-proxy kubelet docker flanneld;do systemctl restart $SERVICES;systemctl enable $SERVICES;systemctl status $SERVICES; done

•验证集群是否安装成功
在master上执行如下命令

[root@master ~]# kubectl get node
NAME            STATUS    AGE
192.168.30.21   Ready     1m
192.168.30.22   Ready     1m
192.168.30.23   Ready     1m
192.168.30.24   Ready     1m

*注释:上述4个节点正常显示，状态为Ready，则说明集群搭建成功，至于集群的应用会在后续文章中介绍。