# k8s 安裝移除
## Installation
<https://zhuanlan.zhihu.com/p/612051521>
<https://blog.jks.coffee/on-premise-self-host-kubernetes-k8s-setup/>
https://earthly.dev/blog/deploy-kubernetes-cri-o-container-runtime/

建議 **`sudo su` 後在 root 權限下執行**

### Setup
- 關閉 swap

    swapoff -a

- Forwarding IPv4 and letting iptables see bridged traffic

    cat <<EOF | sudo tee /etc/modules-load.d/k8s.conf
    overlay
    br_netfilter
    EOF

    modprobe overlay
    modprobe br_netfilter

    # 设置所需的 sysctl 参数
    cat <<EOF | sudo tee /etc/sysctl.d/k8s.conf
    net.bridge.bridge-nf-call-iptables  = 1
    net.bridge.bridge-nf-call-ip6tables = 1
    net.ipv4.ip_forward                 = 1
    EOF

    # 应用 sysctl 参数
    sysctl --system

    # 检验配置是否生效
    lsmod | grep br_netfilter
    lsmod | grep overlay

    sysctl net.bridge.bridge-nf-call-iptables net.bridge.bridge-nf-call-ip6tables net.ipv4.ip_forward

### Container Runtime
follow the instructions on [Getting started with containerd](https://github.com/containerd/containerd/blob/main/docs/getting-started.md)
Dowload page for [containerd](https://containerd.io/downloads/)

- 安裝

    # 安裝 containerd
    wget https://github.com/containerd/containerd/releases/download/$VERSION/containerd-$VERSION-$OS-$ARCH.tar.gz
    tar Cxzvf /usr/local containerd-$VERSION-$OS-$ARCH.tar.gz

    # 設定 systemd
    # make sure if containerd.service store roght data
    wget https://raw.githubusercontent.com/containerd/containerd/main/containerd.service -o /usr/lib/systemd/system/containerd.service
    systemctl daemon-reload && systemctl enable containerd

    # 安裝 runc
    wget https://github.com/opencontainers/runc/releases/download/$VERSION/runc.$ARCH
    install -m 755 runc.$ARCH /usr/local/sbin/runc

    # 安裝 CNI plugins
    mkdir -p /opt/cni/bin
    wget https://github.com/containernetworking/plugins/releases/download/$VERSION/cni-plugins-$OS-$ARCH-$VERSION.tgz
    tar Cxzvf /opt/cni/bin cni-plugins-$OS-$ARCH-$VERSION.tgz

    # 產生 containerd 預設檔案
    mkdir /etc/containerd
    containerd config default > /etc/containerd/config.toml

- 修改設定檔案
/etc/containerd/config.toml

[plugins."io.containerd.grpc.v1.cri".containerd.runtimes.runc]
...
  [plugins."io.containerd.grpc.v1.cri".containerd.runtimes.runc.options]
-    SystemdCgroup = false
+    SystemdCgroup = true
...

- 重啟 containerd

    systemctl restart containerd

- 查看使用的 port

    netstat -nlput | grep containerd

### kubeadm kubelet kubectl

[K8s doc](https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/install-kubeadm/#installing-kubeadm-kubelet-and-kubectl)

sudo apt-get update
# apt-transport-https may be a dummy package; if so, you can skip that package
sudo apt-get install -y apt-transport-https ca-certificates curl

curl -fsSL https://pkgs.k8s.io/core:/stable:/v1.28/deb/Release.key | sudo gpg --dearmor -o /etc/apt/keyrings/kubernetes-apt-keyring.gpg

echo 'deb [signed-by=/etc/apt/keyrings/kubernetes-apt-keyring.gpg] https://pkgs.k8s.io/core:/stable:/v1.28/deb/ /' | sudo tee /etc/apt/sources.list.d/kubernetes.list

sudo apt-get update
sudo apt-get install -y kubelet kubeadm kubectl
sudo apt-mark hold kubelet kubeadm kubectl # set package not to update

## Setup Cluster

### initialize cluster

# only do on master
sudo kubeadm init \
--pod-network-cidr=10.244.0.0/16 \
--cri-socket unix:///var/run/containerd/containerd.sock \ # if only one CRI is installed, then will auotmaic select it. Otherwise will need to set it
--apiserver-advertise-address=$HOST_IP # default is local IP

### join the node

# master
# generate the command for joinging the worker
kubeadm token create --print-join-command \
--cri-socket unix:///var/run/containerd/containerd.sock # if only one CRI is installed, then will auotmaic select it. Otherwise will need to set it

# worker
# copy the command generated form master above
kube kubeadm join ...

### label the role of node

kubectl label node $node kubernetes.io/role=$role

## Remove

1. 移除 node

    kubectl drain $node

<https://kubernetes.io/docs/reference/generated/kubectl/kubectl-commands#drain>
2. 清除安裝時的設定

    sudo kubeadm reset

<https://kubernetes.io/docs/reference/setup-tools/kubeadm/kubeadm-reset/>
3. 刪除其他相關設定
[reset and uninstall](https://github.com/DeepSpider/kubernetes-installation/blob/main/04-reset_uninstall.sh)
[洗掉 kubernetes 環境重新來過](https://ithelp.ithome.com.tw/articles/10262330)