五分钟单机离线安装k8s 1.20版本用于开发测试(k3s版)

五分钟，看是噱头。其实文件下载到位的话，一分钟，也不是不可能。

一，官网

https://k3s.io/

二，文档

https://rancher.com/docs/k3s/latest/en/

三，下载

http://mirror.cnrancher.com/
进入到k3s的v1.20.0-k3s2/目录下载k3s和k3s-airgap-images-amd64.tar文件。
而k3s-install.sh在上一级目录。

• k3s：k3s的可执行文件，kubectl别名

• k3s-airgap-images-amd64.tar：离线安装镜像包

• k3s-install.sh：安装脚本

四，安装过程

1，先安装依赖（如果需要）

yum install -y container-selinux selinux-policy-base
yum install -y https://rpm.rancher.io/k3s-selinux-0.1.1-rc1.el7.noarch.rpm

2，将k3s拷贝到可执行目录

以下步骤使用root帐号
cp k3s /usr/local/bin/

3，设置环境变量

export INSTALL_K3S_SKIP_DOWNLOAD=true

export INSTALL_K3S_EXEC="--docker --bind-address=1.2.3.4 \
    kube-apiserver-arg service-node-port-range=30000-50000 \
    --no-deploy traefik \
    --no-deploy servicelb \
    --no-deploy local-storage \
    --no-deploy metrics-server  \
    --write-kubeconfig ~/.kube/config \
    --write-kubeconfig-mode 666"

• 本地已有镜像，无须下载
• 使用docker服务，无须部署servicelb, traefik, local-storage, metrics-server
• 可选禁用项：coredns, servicelb, traefik,local-storage, metrics-server

4，运行安装脚本

sh k3s-install.sh
输出

[INFO]  Skipping k3s download and verify
[INFO]  Skipping installation of SELinux RPM
[INFO]  Creating /usr/local/bin/kubectl symlink to k3s
[INFO]  Skipping /usr/local/bin/crictl symlink to k3s, command exists in PATH at /usr/bin/crictl
[INFO]  Skipping /usr/local/bin/ctr symlink to k3s, command exists in PATH at /usr/bin/ctr
[INFO]  Creating killall script /usr/local/bin/k3s-killall.sh
[INFO]  Creating uninstall script /usr/local/bin/k3s-uninstall.sh
[INFO]  env: Creating environment file /etc/systemd/system/k3s.service.env
[INFO]  systemd: Creating service file /etc/systemd/system/k3s.service
[INFO]  systemd: Enabling k3s unit
[INFO]  systemd: Starting k3s

5，获取kubeconfig文件

cat ~/.kube/config
以下步骤使用普通帐号，将root下的kubeconfig文件内容，cp到普通帐号的对应目录即可。

6，测试yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
spec:
  selector:
    matchLabels:
      app: nginx
  replicas: 1
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.18-alpine
        imagePullPolicy: IfNotPresent
        ports:
        - containerPort: 80
---
apiVersion: v1
kind: Service
metadata:
  name: nginx-service
spec:
  selector:
    app: nginx
  ports:
  - protocol: TCP
    name: http
    port: 80
    targetPort: 80
  type: NodePort