CentOS下的安装测试K8S（守护进程式）

master: 192.168.0.100

node1: 192.168.0.105
node2: 192.168.0.106

 一,k8s基本操作命令：

k8s全名：kubernetes,
容器编排工具，说白了就是自动化管理容器的工具。包括:

• 服务自动注册和发现
• 负载均衡
• 健康监测
• 自动申缩
• 冗余容灾

基本操作命令：

创建：kubectl create -f xxx.yaml
     kubectl apply -f xxx.yaml
查询：
kubectl get pod yourPodName

kubectl describe pod yourPodName //这个我一般用来排查机器无故没有Running

删除：kubectl delete pod yourPodName
强制删除: kubectl delete pod PODNAME --force --grace-period=0

更新：kubectl replace /path/to/yourNewYaml.yaml

二,k8s_master安装配置:

2.1,关闭selinux,关闭防火墙,升级yum

setenforce 0
systemctl stop firewalld.service
yum update

2.2,安装并配置k8s

yum -y install epel-release

yum -y install etcd kubernetes-master

#配置
vi /etc/etcd/etcd.conf
vi /etc/kubernetes/apiserver

2.3,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

2.4,定义flannel网络
etcdctl mk /atomic.io/network/config '{"Network":"172.17.0.0/16"}'

三,k8s_node安装配置:

3.1,关闭selinux,关闭防火墙,升级yum

setenforce 0
systemctl stop firewalld.service
yum update

3.2,安装docker,并配置阿里云加速

yum install docker
docker -v ##查看版本
service docker start ##开启docker服务才能用其他命令
chkconfig docker on
docker images

配置vim /etc/docker/daemon.json

{
"registry-mirrors": [ "https://cd6xo91e.mirror.aliyuncs.com"]
}

3.3,安装并配置k8s,,并启动

yum -y install epel-release
yum -y install flannel kubernetes-node

#配置
vi /etc/sysconfig/flanneld
vi /etc/kubernetes/config
vi /etc/kubernetes/kubelet

3.4,node节点机上启动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

四,编排

创建/root/k8s/tomcat01.yaml文件

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: myweb
spec:
  replicas: 3
  template:
    metadata:
      name: test-namespace
      labels:
        app: myweb
    spec:
      containers:
      - name: myweb
        image: docker.io/nginx:1.18.0-alpine
        ports:
        - containerPort: 80

---
apiVersion: v1
kind: Service
metadata:
  name: myweb
spec:
   ports:
   - port: 80
     targetPort: 80
     nodePort: 31111
   selector:
     app: myweb
   type: NodePort

nginx开放的80,如果是tomcat开放的8080,文件里面80都改成8080即可

kubectl create -f tomcat01.yaml

#如果配置错了，创建了一个错误的service和pod，可以用删除命令，配置正确后再重新创建一遍
kubectl delete -f tomcat01.yaml

检查一下pod和service:

kubectl get pods -o wide

kubectl get svc

#如果两个pods的状态都是ContainerCreating，而不是running，说明kubectl create -f xxx操作是失败的,察看日志
kubectl describe pods myweb-3889544643-3sxrb

五、排障，测试

5.1 错误:redhat-ca.crt
解决方法:

yum install *rhsm* -y

5.2 错误:kubelet does not have ClusterDNS IP configured and cannot create Pod using "ClusterFirst" policy. Fail
解决方法:

master:
通过环境变量，配置参数
[root@k8s-master dns]# vi ~/.bash_profile #添加下面三行

export DNS_SERVER_IP="10.254.10.2"
export DNS_DOMAIN="cluster.local"
export DNS_REPLICAS=1

设置 Cluster DNS Service的IP为 10.254.10.2（不能和已分配的IP重复，如10.0.10.0），Cluster DNS的本地域为 cluster.local。

node:
在vi /etc/kubernetes/kubelet 配置文件中添加如下内容即可

KUBE_ARGS="--cluster-dns=10.254.10.2 --cluster-domain=cluster.local"
重启
systemctl daemon-reload; systemctl restart kubelet