kubernetes 1.20.0安装

1. 安装要求

一台或多台机器，操作系统CentOS-7以上
硬件配置：2GB或更多RAM，2个CPU或更多CPU，硬盘30GB或- 更多
集群中所有机器网络互通
可以访问外网，需要拉取镜像
禁止swap分区

2. 准备环境

本人买了三台云服务器，配置如下:

node_name	ip	CPU	RAM	硬盘	宽带
k8s-master	172.31.0.60	2核	4G	40G	3Mb/s
k8s-node01	172.31.0.224	2核	4G	40G	3Mb/s
k8s-node02	172.31.0.237	2核	4G	40G	3Mb/s

# 关闭swap分区
swapoff -a && sed -i '/ swap / s/^\(.*\)$/#\1/g' /etc/fstab
# 关闭防火墙
systemctl stop firewalld && systemctl disable firewalld
# 关闭selinux 
setenforce 0 && sed -i 's/^SELINUX=.*/SELINUX=disabled/' /etc/selinux/config

设置主机名

hostnamectl set-hostname <hostname>

在master添加hosts

cat >> /etc/hosts << EOF
127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6
172.31.0.60 k8s-master
172.31.0.224 k8s-node01
172.31.0.237 k8s-node02
EOF

3 安装Docker、kubeadm、kubelet【所有节点】

Kubernetes默认CRI（容器进行时）为Docker，因此先安装Docker

3.1 安装Docker

# 安装依赖包
yum install -y yum-utils
# 添加Docker软件包源
yum-config-manager \
--add-repo \
https://download.docker.com/linux/centos/docker-ce.repo
# 安装Docker CE
yum install -y docker-ce
# 启动Docker服务并设置开机启动
systemctl start docker
systemctl enable docker
# 配置阿里云镜像加速器
cat > /etc/docker/daemon.json << EOF
{
"registry-mirrors": ["https://obhube46.mirror.aliyuncs.com"],
"exec-opts": ["native.cgroupdriver=systemd"],
"log-driver": "json-file",
"log-opts": {
"max-size": "100m"
}
}
EOF
# 重启docker，使其生效
systemctl restart docker

3.2 添加阿里云YUM软件源

cat > /etc/yum.repos.d/kubernetes.repo << EOF
[kubernetes]
name=Kubernetes
baseurl=http://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64
enabled=1
gpgcheck=0
repo_gpgcheck=0
gpgkey=http://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg http://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
EOF

3.3 安装Kubeadm,kubelet和kubectl

由于版本更新频繁，这里指定版本号部署

# 查看kubelet kubeadm kubectl版本
yum list kubelet kubeadm kubectl  --showduplicates|sort -r
# 安装指定版本
yum -y install kubeadm-1.20.0 kubectl-1.20.0 kubelet-1.20.0
systemctl enable kubelet.service

4 部署Kubernetes Master

kubernetes-version：具体安装的实际版本
kubelet --version 命令获取；
apiserver-advertise-address：master机器的IP

kubeadm init --kubernetes-version=1.20.0 \
--apiserver-advertise-address=172.31.0.60 \
--image-repository registry.aliyuncs.com/google_containers \
--service-cidr=10.96.0.0/12 \
--pod-network-cidr=10.244.0.0/16 \
--ignore-preflight-errors=all
# 配置kubectl配置
mkdir -p $HOME/.kube
sudo cp -f /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
# 获取node状态
kubectl get nodes
# 可能报错1：Unable to connect to the server: dial tcp: lookup localhost on 114.114.114.114:53: no such host
# 解决办法：添加/etc/hosts localhost映射
cat >> /etc/hosts << EOF
127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6
EOF
# 可能报错2：The connection to the server localhost:8080 was refused - did you specify the right host or port?
# 解决办法：添加配置文件到环境变量
echo "export KUBECONFIG=/etc/kubernetes/admin.conf" >> /etc/profile
source /etc/profile

kubeadm init做了哪些工作:

[preflight] 环境监察和拉取镜像（kubeadm config images pull）
[certs]创建证书目录/etc/kubernetes/pki，生成证书
[kubeconfig]创建连接apiserver的配置文件目录/etc/kubernetes
[kubelet-start]生成kubelet配置文件和启动
[control-plane]使用静态的pod启动master组件/etc/kubernetes/maintests
[upload-config][upload-certs][kubelet]使用ConfigMap存储kubelet配置
[mark-control-plane]给master节点添加标签
[bootstrap-token]kubelet自动申请证书机制
[addons]安装插件CoreDNS和kube-proxy

5 加入Kubernetes Node

分别在k8s-node01,k8s-node02上执行（kubeadm init时的log）

kubeadm join 172.31.0.60:6443 --token i8px88.bpy0zxxc7jjgbnv8 \
    --discovery-token-ca-cert-hash sha256:cf418940ea74bf58ba99eca57e960fdef8a381932cad2f77c37e45e79610e02f

6 部署容器网络CNI

在master节点安装

wget https://docs.projectcalico.org/manifests/calico.yaml
sed -i 's/192.168.0.0/10.244.0.0/g' calico.yaml
kubectl apply -f calico.yaml

过一会，可看到节点由NotReady状态转为Ready状态，即安装完成.

kubectl get nodes
# NAME         STATUS   ROLES                  AGE   VERSION
# k8s-master   Ready    control-plane,master   16m   v1.20.0
# k8s-node01   Ready    <none>                 16m   v1.20.0
# k8s-node02   Ready    <none>                 15m   v1.20.0

7 测试kubernetes集群之快速部署一个网站

在Kubernetes集群中创建一个pod，验证是否正常运行

# 使用Deployment控制器部署镜像
kubectl create deployment nginx --image=nginx
# 使用Service将Pod暴露出去
kubectl expose deployment nginx --port=80 --target-port=80 --type=NodePort
# 获取随机生成的端口
kubectl get pod,svc

访问地址，需要使用公网Ip，端口随机生成，通过get svc获取，在安全组配置端口，允许入方向
http://NodeIP:Port

# 可能报错：get pod时，pod一直处于"ContainerCreating"状态，通过 describe pod 查看日志得到报错如下
kubectl get pod
kubectl describe pod <nginx-pod-name>
# stat /var/lib/calico/nodename: no such file or directory: check that the calico/node container  is running and has mounted /var/lib/calico/
# 解决办法：
#创建目录和文件
mkdir /var/lib/calico/
touch /var/lib/calico/nodename
#将本机ip写进nodename文件中
echo "172.31.0.60" > /var/lib/calico/nodename

验证port工作

kubectl get pod
# nginx的pod处于running状态

验证Pod网络通信

kubectl get pods -o wide
#NAME                     READY   STATUS    RESTARTS   AGE   IP              NODE         NOMINATED NODE   READINESS GATES
#nginx-6799fc88d8-zt54g   1/1     Running   0          12m   10.244.85.193   k8s-node01   <none>           <none>
# 在所有节点ping Pod IP，能正常ping通
ping 10.244.85.193

验证DNS解析

kubectl get pods -n kube-system
# coredns 处于running状态

8 部署Dashboard

wget http://raw.githubusercontent.com/kubernetes/dashboard/v2.0.3/aio/deploy/recommended.yaml
mv recommended.yaml kubernetes-dashboard.yaml

vim kubernetes-dashboard.yaml
# 添加 nodePort: 30001 , type: NodePort
....
---

kind: Service
apiVersion: v1
metadata:
  labels:
    k8s-app: kubernetes-dashboard
  name: kubernetes-dashboard
  namespace: kubernetes-dashboard
spec:
  ports:
    - port: 443
      targetPort: 8443
      nodePort: 30001
  selector:
    k8s-app: kubernetes-dashboard
  type: NodePort
---
...

# 更改完成后，运行启动dashboard
kubectl apply -f kubernetes-dashboard.yaml
# 获取pod状态，确认为running状态，则安装成功
kubectl get pods -n kubernetes-dashboard

访问地址：
https://公网Ip:30001
创建service account并绑定默认的cluster-admin管理员集群角色：

# 创建用户
kubectl create serviceaccount dashboard-admin -n kube-system
# 用户授权
kubectl create clusterrolebinding dashboard-admin --clusterrole=cluster-admin --serviceaccount=kube-system:dashboard-admin
# 获取用户Token
kubectl describe secrets -n kube-system $(kubectl -n kube-system get secret | awk '/dashboard-admin/{print $1}')

原文链接：https://blog.csdn.net/weixin_43872526/article/details/123611518