centos 7.6.180 安装 Kubernetes 1.17.3

1 准备三台虚拟机

配置2核2G

 172.16.159.165 master1.k8s 
 172.16.159.166 node1.k8s
 172.16.159.167 node2.k8s

修改主机名
在master1.k8s （172.16.159.165）上：
hostnamectl set-hostname master1.k8s 

node1.k8s（172.16.159.166）上：
hostnamectl set-hostname node1.k8s

node2.k8s（172.16.159.167）上：
hostnamectl set-hostname node2.k8s

2 修改hosts

master1.k8s,node1.k8s,node2.k8s 三台机器都需要操作。

cat >> /etc/hosts << EOF 
 172.16.159.165 master1.k8s 
 172.16.159.166 node1.k8s
 172.16.159.167 node2.k8s
EOF

3 关闭防火墙，禁用selinux，禁用 swap

master1.k8s,node1.k8s,node2.k8s 三台机器都需要操作。

3.1 关闭防火墙

关闭并禁用防火墙
[root@master1 ~]# systemctl stop firewalld && systemctl disable firewalld
Removed symlink /etc/systemd/system/multi-user.target.wants/firewalld.service.
Removed symlink /etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service.

查看默认防火墙状态（关闭后显示not running，开启后显示running）
[root@master1 ~]# firewall-cmd --state
not running

清除防火墙规则（否则pod及容器无法跨主机互通问题）

iptables -P INPUT ACCEPT
iptables -P FORWARD ACCEPT
iptables -F
iptables -L -n

3.2 禁用selinux

关闭Selinux
[root@master1 ~]# setenforce 0
[root@master1 ~]# sed -i "s/SELINUX=enforcing/SELINUX=disabled/g" /etc/selinux/config

重启
[root@master1 ~]# reboot

查看Selinux状态
[root@master1 ~]# sestatus
SELinux status:                 disabled

3.3 禁用swap

[root@master1 ~]# swapoff -a
[root@master1 ~]# sed -i 's/.*swap.*/#&/' /etc/fstab
[root@master1 ~]# free
              total        used        free      shared  buff/cache   available
Mem:        2030472       79496     1826568        8952      124408     1797140
Swap:             0           0           0
[root@master1 ~]#

4 修改系统配置

4.1 net.bridge

一些 RHEL/CentOS 7 的用户曾经遇到过问题：
由于 iptables 被绕过而导致流量无法正确路由的问题。
您应该确保 在sysctl 配置中的 net.bridge.bridge-nf-call-iptables 被设置为 1

# cat <  /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
EOF
# sysctl --system

5 同步时间

因为虚拟机有可能经常关机，与本地时间不同步，安装k8s有可能失败

# yum -y install ntp
# ntptime
# timedatectl

时间同步

ntpdate cn.pool.ntp.org

编辑计划任务，每小时做一次同步

crontab -e
0 * * * * /usr/sbin/ntpdate cn.pool.ntp.org

6 安装docker

master1.k8s,node1.k8s,node2.k8s 三台机器都需要操作。
《centos 7.6.1810安装与使用docker 18.09.6》：https://blog.csdn.net/CleverCode/article/details/107181446

7 安装Kubernetes

7.1 安装Kubernetes

master1.k8s,node1.k8s,node2.k8s 三台机器都需要操作。

1 配置国内kubernetes源

cat < /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64/
enabled=1
gpgcheck=1
repo_gpgcheck=1
gpgkey=https://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg https://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
EOF

2 安装 kubelet、kubeadm、kubectl

kubelet 负责与其他节点集群通信，并进行本节点pod和容器生命周期的管理。
kubeadm 是kubernetes的自动化部署工具，降低了部署难度，提高效率。
kubectl 是kubernetes集群管理工具。

安装
# yum install -y  kubelet-1.17.3 kubeadm-1.17.3 kubectl-1.17.3

设置开机自启
# systemctl enable kubelet && systemctl start kubelet

8 配置Kubernetes

8.1 配置master

在master1.k8s 操作

8.1.1 初始化主节点

# kubeadm init --kubernetes-version="v1.17.3" --pod-network-cidr="10.16.0.0/8" --image-repository registry.aliyuncs.com/google_containers

k8s 主节点初始化成功后日志

Your Kubernetes control-plane has initialized successfully!

To start using your cluster, you need to run the following as a regular user:

  mkdir -p $HOME/.kube
  sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
  sudo chown $(id -u):$(id -g) $HOME/.kube/config

You should now deploy a pod network to the cluster.
Run "kubectl apply -f [podnetwork].yaml" with one of the options listed at:
  https://kubernetes.io/docs/concepts/cluster-administration/addons/

Then you can join any number of worker nodes by running the following on each as root:

kubeadm join 172.16.159.165:6443 --token yxmvci.hio9tpu4b58phpgm \
    --discovery-token-ca-cert-hash sha256:fa1e09d4bca3a95b53398212457827467a2a720489223123116223bb7a576a68

查看初始化完成后拉取到的镜像

查看运行的容器

根据控制台日志依次执行下面

[root@master1 ~]# mkdir -p $HOME/.kube
[root@master1 ~]# sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
[root@master1 ~]# sudo chown $(id -u):$(id -g) $HOME/.kube/config

验证各组件是否正常

[root@master1 ~]# kubectl get cs
NAME                 STATUS    MESSAGE             ERROR
controller-manager   Healthy   ok
scheduler            Healthy   ok
etcd-0               Healthy   {"health":"true"}
[root@master1 ~]#

执行 kubectl get nodes，查看k8s 节点，状态未就绪

8.1.2 联网配置

下载kube-flannel.yml
wget https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
kubectl apply -f kube-flannel.yml 

刚开始一直NotReady，重启之后就好了，变成Ready了。

8.2 配置node

node1.k8s,node2.k8s 执行 初始化8.1主节点之后的提示信息

kubeadm join 172.16.159.165:6443 --token yxmvci.hio9tpu4b58phpgm \
    --discovery-token-ca-cert-hash sha256:fa1e09d4bca3a95b53398212457827467a2a720489223123116223bb7a576a68

9 查看

9.1 查看node

执行完8.2操作后，过几分钟，在master1.k8s执行。node节点从 NotReady变成Ready了。

查看所有节点
[root@master1 ~]# kubectl get nodes
NAME          STATUS   ROLES    AGE     VERSION
master1.k8s   Ready    master   49m     v1.17.3
node1.k8s     Ready    <none>   3m34s   v1.17.3
node2.k8s     Ready    <none>   2m53s   v1.17.3

-o wide 显示详情
[root@master1 ~]# kubectl get nodes -o wide
NAME          STATUS   ROLES    AGE     VERSION   INTERNAL-IP      EXTERNAL-IP   OS-IMAGE                KERNEL-VERSION                CONTAINER-RUNTIME
master1.k8s   Ready    master   50m     v1.17.3   172.16.159.165   <none>        CentOS Linux 7 (Core)   4.4.229-1.el7.elrepo.x86_64   docker://18.9.6
node1.k8s     Ready    <none>   4m30s   v1.17.3   172.16.159.166   <none>        CentOS Linux 7 (Core)   4.4.229-1.el7.elrepo.x86_64   docker://18.9.6
node2.k8s     Ready    <none>   3m49s   v1.17.3   172.16.159.167   <none>        CentOS Linux 7 (Core)   4.4.229-1.el7.elrepo.x86_64   docker://18.9.6

9.2 查看Pod

# 查看所有pod 必须指定命名空间
kubectl get pods -n kube-system
# -n kube-system 指定命名空间
# -o wide 显示详情信息
kubectl get pods -n kube-system -o wide

[root@master1 ~]# kubectl get pods -n kube-system -o wide
NAME                                  READY   STATUS    RESTARTS   AGE   IP               NODE          NOMINATED NODE   READINESS GATES
coredns-9d85f5447-2sssz               1/1     Running   0          97m   10.0.0.3         master1.k8s   <none>           <none>
coredns-9d85f5447-ndwpt               1/1     Running   0          97m   10.0.0.2         master1.k8s   <none>           <none>
etcd-master1.k8s                      1/1     Running   1          96m   172.16.159.165   master1.k8s   <none>           <none>
kube-apiserver-master1.k8s            1/1     Running   1          96m   172.16.159.165   master1.k8s   <none>           <none>
kube-controller-manager-master1.k8s   1/1     Running   1          96m   172.16.159.165   master1.k8s   <none>           <none>
kube-flannel-ds-amd64-84gnt           1/1     Running   0          50m   172.16.159.167   node2.k8s     <none>           <none>
kube-flannel-ds-amd64-lp8hf           1/1     Running   0          51m   172.16.159.166   node1.k8s     <none>           <none>
kube-flannel-ds-amd64-zwdq7           1/1     Running   0          70m   172.16.159.165   master1.k8s   <none>           <none>
kube-proxy-4hxl9                      1/1     Running   1          97m   172.16.159.165   master1.k8s   <none>           <none>
kube-proxy-8ppds                      1/1     Running   0          51m   172.16.159.166   node1.k8s     <none>           <none>
kube-proxy-pmjs5                      1/1     Running   0          50m   172.16.159.167   node2.k8s     <none>           <none>
kube-scheduler-master1.k8s            1/1     Running   1          96m   172.16.159.165   master1.k8s   <none>           <none>
[root@master1 ~]#

参考文档

https://www.cnblogs.com/gmmy/p/12372805.html

https://blog.csdn.net/fp19930214/article/details/104919677

http://www.mamicode.com/info-detail-2950096.html

https://blog.csdn.net/freedom00001/article/details/104462944