在centos 7中安装配置k8s集群的步骤详解

配置背景介绍

kubernetes是google开源的容器集群管理系统，提供应用部署、维护、扩展机制等功能，利用kubernetes能方便管理跨集群运行容器化的应用，简称：k8s（k与s之间有8个字母）

为什么要用kubernetes这么复杂的docker集群管理工具呢？一开始接触了docker内置的swarm，这个工具非常简单快捷的完成docker集群功能。但是在使用docker1.13内置的swarm做集群的时候遇到vip负载均衡没有正确映射端口到外网，或者出现地址被占用的情况，这对高可用性的需求是不利的，然而又没找到一个解决方案，只能转投k8s。

实验环境

• 腾讯云
• centos7.3 64位

安装

yum-config-manager --add-repo https://docs.docker.com/v1.13/engine/installation/linux/repo_files/centos/docker.repo 
yum makecache fast 
yum -y install docker-engine-1.13.1 
yum install epel-release -y 
yum remove -y docker-engine* 
yum install -y kubernetes etcd docker flannel

修改配置文件

注意下面的10.135.163.237换成自己服务器ip

sed -i "s/localhost:2379/10.135.163.237:2379/g" /etc/etcd/etcd.conf

sed -i "s/localhost:2380/10.135.163.237:2380/g" /etc/etcd/etcd.conf

sed -i "s/10.135.163.237:2379/10.135.163.237:2379,http:\/\/127.0.0.1:2379/g" /etc/etcd/etcd.conf


sed -i "s/127.0.0.1:2379/10.135.163.237:2379/g" /etc/kubernetes/apiserver

sed -i "s/--insecure-bind-address=127.0.0.1/--insecure-bind-address=0.0.0.0/g" /etc/kubernetes/apiserver

sed -i "s/--admission-control=NamespaceLifecycle,NamespaceExists,LimitRanger,SecurityContextDeny,ServiceAccount,ResourceQuota/--admission_control=NamespaceLifecycle,NamespaceExists,LimitRanger,ResourceQuota/g" /etc/kubernetes/apiserver



sed -i "s/--hostname-override=127.0.0.1/--hostname-override=10.135.163.237/g" /etc/kubernetes/kubelet


sed -i "s/127.0.0.1:8080/10.135.163.237:8080/g" /etc/kubernetes/kubelet


sed -i "s/--address=127.0.0.1/--address=0.0.0.0/g" /etc/kubernetes/kubelet


sed -i "s/127.0.0.1:8080/10.135.163.237:8080/g" /etc/kubernetes/config

sed -i "s/127.0.0.1:2379/10.135.163.237:2379/g" /etc/sysconfig/flanneld

修改host

vi /etc/hosts 
10.135.163.237 k8s_master

添加网络

systemctl enable etcd.service

systemctl start etcd.service

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

启动服务

service docker start 
for SERVICES in etcd kube-apiserver kube-controller-manager kube-scheduler kube-proxy kubelet docker flanneld ; do systemctl restart $SERVICES; systemctl enable $SERVICES; systemctl status $SERVICES; done;

第一个demo

编写文件a.yaml

apiVersion: extensions/v1beta1 
kind: Deployment 
metadata: 
 name: my-app
spec: 
 replicas: 2
 template:
 metadata:
 labels:
 app: my-app
 spec:
 containers:
 - name: my-app
 image: registry.alauda.cn/yubang/paas_base_test
 ports:
 - containerPort: 80
 command: ["/bin/bash", "/var/start.sh"] 
 resources: 
  limits: 
  cpu: 0.5 
  memory: 64Mi

编写文件b.yaml

apiVersion: v1 
kind: Service 
metadata: 
 name: my-app-svc
 labels:
 app: my-app
spec: 
 ports:
 - port: 80
 targetPort: 80
 nodePort: 30964
 type: NodePort
 selector:
 app: my-app

创建服务

kubectl create -f a.yaml --validate 
kubectl create -f b.yaml --validate

删除服务

kubectl delete -f a.yaml 
kubectl delete -f b.yaml

增加子节点

安装软件

yum-config-manager --add-repo https://docs.docker.com/v1.13/engine/installation/linux/repo_files/centos/docker.repo 
yum makecache fast 
yum -y install docker-engine-1.13.1 
yum install epel-release -y 
yum remove -y docker-engine* 
yum install -y kubernetes docker flannel

修改配置文件（10.135.163.237为主节点ip，139.199.0.29为当前节点ip）

sed -i "s/--hostname-override=127.0.0.1/--hostname-override=139.199.0.29/g" /etc/kubernetes/kubelet


sed -i "s/127.0.0.1:8080/10.135.163.237:8080/g" /etc/kubernetes/kubelet


sed -i "s/--address=127.0.0.1/--address=0.0.0.0/g" /etc/kubernetes/kubelet

sed -i "s/127.0.0.1:8080/10.135.163.237:8080/g" /etc/kubernetes/config

sed -i "s/127.0.0.1:2379/10.135.163.237:2379/g" /etc/sysconfig/flanneld

sed -i "s/--admission-control=NamespaceLifecycle,NamespaceExists,LimitRanger,SecurityContextDeny,ServiceAccount,ResourceQuota/--admission_control=NamespaceLifecycle,NamespaceExists,LimitRanger,ResourceQuota/g" /etc/kubernetes/apiserver

启动服务

service docker start

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

在主服务器查看节点

kubectl get node

重启服务（重新加入集群）

systemctl restart kube-apiserver.service

删除节点

kubectl delete node 节点ip

总结