今天使用的是兩個VM VirtualBox Ubuntu20.04，配置如下:

• Master
  • 主機名稱:master
  • CPU : 2core
  • RAM : 4G
• Node
  • 主機名稱:node
  • CPU : 1core
  • RAM : 4G

在安裝k8s前，請先確認是否已安裝好Docker。

安裝Docker的步驟如下:

sudo apt update
sudo apt-get install apt-transport-https ca-certificates curl software-properties-common
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -
sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu  $(lsb_release -cs)  stable"
sudo apt-get install docker-ce
docker --version 
sudo systemctl start docker 
sudo systemctl enable docker 
sudo systemctl status docker 

安裝好Docker之後，就開始安裝k8s吧。

在Master跟worker執行

sudo su -c "curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | apt-key add -"
sudo apt-add-repository "deb http://apt.kubernetes.io/ kubernetes-xenial main"
sudo apt update

version=1.18.20-00
echo $version
apt-cache show kubectl | grep "Version: 1.18.20-00"
# Install k8s
sudo swapoff -a
sudo sed -i '/ swap / s/^\(.*\)$/#\1/g' /etc/fstab
sudo apt install -y kubelet=$version kubectl=$version kubeadm=$version
sudo apt-mark hold kubelet kubeadm kubectl

cat <<EOF | sudo tee /etc/docker/daemon.json
{
  "exec-opts": ["native.cgroupdriver=systemd"],
  "log-driver": "json-file",
  "log-opts": {
    "max-size": "100m"
  },
  "storage-driver": "overlay2"
}
EOF

sudo mkdir -p /etc/systemd/system/docker.service.d
sudo systemctl daemon-reload
sudo systemctl restart docker

只在Master執行

sudo kubeadm init --v=5 --pod-network-cidr=10.244.0.0/16
mkdir -p $HOME/.kube
cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
chown $(id -u):$(id -g) $HOME/.kube/config

初始化結束後，會拿到一串指令:

kubeadm join 192.168.1.111:6443 --token 1p1r4a.9eh3cybvgw8tdvju \
    --discovery-token-ca-cert-hash sha256:7b14f09e50c9d8d5e88ce10bad16034d71da947bbdeb124c9e0438ae400c543a 

再來就可以用這串指令，讓Node加入到此叢集了。再來執行kubectl get node確認一下。

root@master:/home/ubuntu# kubectl get node
NAME     STATUS     ROLES    AGE    VERSION
master   NotReady   master   4m7s   v1.18.20
node     NotReady   <none>   83s    v1.18.20

確定有master和node之後，你會發現status顯示NotReady，這時只要輸入下面的指令去部署CNI:

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

等待一下，再次執行kubectl get node:

root@master:/home/ubuntu# kubectl get node
NAME     STATUS   ROLES    AGE     VERSION
master   Ready    master   4m23s   v1.18.20
node     Ready    <none>   99s     v1.18.20