k3s脚本快速安装

# k3s脚本快速安装
为了快速部署测试环境用于测试一些开源中间件或系统，所以安装k3s作为测试环境。

## 环境要求
```shell
# 系统内核版本：Linux 3.10+ (CentOS 7, Debian 8/9, Ubuntu 14.04+)
# K3S Server端最低内存要求：512 MB
# K3S Agent端内存最低要求：75MB
# 磁盘空间最低要求：200 MB
# 支持的硬件架构：x86_64, ARMv7, ARM64

```
## 安装配置
### hostname设置
```shell
[root@centos-001 ~] hostnamectl set-hostname centos-001

# 主机名必需唯一，否则客户端可能加入不到server端
```

### server安装
```shell
[root@centos-001 ~] curl https://releases.rancher.com/install-docker/19.03.sh | sh
[root@centos-001 ~] curl -sfL http://rancher-mirror.cnrancher.com/k3s/k3s-install.sh |INSTALL_K3S_VERSION=v1.20.14+k3s1 INSTALL_K3S_MIRROR=cn  K3S_DATASTORE_ENDPOINT=etcd   sh -s - --docker --etcd-expose-metrics=true

# 会作为一个systemd服务运行, 支持开机自启动
# 会安装额外的工具，包括kubectl, crictl, ctr, k3s-killall.sh和k3s-uninstall.sh
# 会生成kubeconfig配置文件/etc/rancher/k3s/k3s.yaml
```

### token查看
```shell
[root@centos-001 ~]# cat /var/lib/rancher/k3s/server/node-token
K108892464b33a36f78370d10085c86a960e3d5bf56a4304acab9b08ef10968a221::server:de73cbbbd324bbe4d98e693b0c11883f

# 该token用于Agent安装时候，传递给K3S_TOKEN参数
```

### agent安装
```shell
[root@centos-002 ~]  curl -sfL http://rancher-mirror.cnrancher.com/k3s/k3s-install.sh | K3S_URL=https://10.20.205.178:6443 K3S_TOKEN=${TOKEN} INSTALL_K3S_VERSION=v1.20.14+k3s1 INSTALL_K3S_MIRROR=cn  sh -s - --docker

# K3S_URL是Server节点的IP地址, 默认端口是6443
# K3S_TOKEN存储在Server节点的/var/lib/rancher/k3s/server/node-token文件中

[root@centos-001 ~]# kubectl get nodes
NAME            STATUS     ROLES                       AGE    VERSION
centos-001   Ready      control-plane,etcd,master   4m7s   v1.20.7+k3s1
centos-002   NotReady   <none>                      33s    v1.20.7+k3s1

# 给节点打worker标签
[root@centos-001 ~]# kubectl label node centos-002 node-role.kubernetes.io/worker=worker

[root@centos-001 ~]# kubectl get nodes
NAME            STATUS     ROLES                       AGE    VERSION
centos-001   Ready      control-plane,etcd,master   4m7s   v1.20.7+k3s1
centos-002   Ready      worker                      33s    v1.20.7+k3s1
```

## 使用
### agent端查看服务
```shell
[root@centos-001 ~] systemctl status k3s-agent

# 如果显示Active: active (running)，则表示客户端正常
```

![](/media/202106/2021-06-03_160710.png)

### server端查看服务
```shell
[root@centos-001 ~] kubectl get nodes
NAME         STATUS   ROLES                  AGE   VERSION
centos-001   Ready    control-plane,master   25h   v1.20.7+k3s1
centos-002   Ready    worker                 25h   v1.20.7+k3s1

# 能够查询到centos--01和centos-002分别为master和worker
```

### 常用命令
```shell

# 验证客户端是否安装成功
[root@centos-002 ~] systemctl status k3s-agent

# 验证服务端是否安装成功
[root@centos-001 ~] kubectl get nodes

# agent端重启
[root@centos-002 ~] service k3s-agent restart

# 检查pod状态
[root@centos-001 ~] k3s kubectl get po --all-namespaces

# 重启k3s服务
[root@centos-001 ~] systemctl restart k3s

# 查看k3s状态
[root@centos-001 ~] systemctl status k3s
```