提前准备
临时关闭 swap。持久关闭，请百度。
$ sudo swapoff -a
一、安装 containerd
1. 安装必要依赖
$ sudo apt-get update
$ sudo apt-get install -y ca-certificates curl gnupg lsb-release
2. 添加 GPG 密钥
$ sudo mkdir -p /etc/apt/keyrings
$ curl -fsSL https://mirrors.aliyun.com/docker-ce/linux/ubuntu/gpg | sudo gpg --dearmor -o /etc/apt/keyrings/docker.gpg
3. 设置 apt 仓库
$ echo \
"deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.gpg] https://mirrors.aliyun.com/docker-ce/linux/ubuntu \
$(lsb_release -cs) stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null
4. 安装 containerd
$ sudo apt-get update
$ sudo apt-get install -y containerd.io
# 锁定 containerd.io 版本
$ sudo apt-mark hold containerd.io
5. 启用 cri 和 systemd
$ containerd config default | sudo tee /etc/containerd/config.toml
找到下面的配置项并修改。
[plugins."io.containerd.grpc.v1.cri"]
sandbox_image = "registry.aliyuncs.com/google_containers/pause:3.7"
...
[plugins."io.containerd.grpc.v1.cri".containerd.runtimes.runc]
...
[plugins."io.containerd.grpc.v1.cri".containerd.runtimes.runc.options]
SystemdCgroup = true
重启 containerd 并设置 containerd 自启动。
$ sudo systemctl restart containerd.service
$ sudo systemctl enable containerd.service
二、安装 Kubeadm
1. 允许 iptables 检查桥接流量
$ cat <<EOF | sudo tee /etc/modules-load.d/k8s.conf
overlay
br_netfilter
EOF
$ sudo modprobe overlay
$ sudo modprobe br_netfilter
$ cat <<EOF | sudo tee /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward = 1
EOF
$ sudo sysctl --system
2. 安装必要依赖
$ sudo apt-get update
$ sudo apt-get install -y apt-transport-https ca-certificates curl
3. 添加 GPG 密钥
$ sudo curl -fsSLo /usr/share/keyrings/kubernetes-archive-keyring.gpg https://mirrors.aliyun.com/kubernetes/apt/doc/apt-key.gpg
4. 设置 apt 仓库
$ echo \
"deb [signed-by=/usr/share/keyrings/kubernetes-archive-keyring.gpg] https://mirrors.aliyun.com/kubernetes/apt/ \
kubernetes-xenial main" | sudo tee /etc/apt/sources.list.d/kubernetes.list
5. 安装 kubelet、kubeadm 和 kubectl，并锁定其版本
$ sudo apt-get update
$ sudo apt-get install -y kubelet kubeadm kubectl
# 锁定 kubelet kubeadm kubectl 版本
$ sudo apt-mark hold kubelet kubeadm kubectl
三、安装 Kubernetes
1. 初始化控制平面节点
$ sudo kubeadm init \
# 设置控制平面端点，子节点通过这个 host/ip 访问控制平面
--control-plane-endpoint=<control-plane-host-or-ip> \
# 设置 pod 的网络的无类别域间路由 ip 段
--pod-network-cidr=10.244.0.0/16 \
# 设置容器运行时
--cri-socket=unix:/run/containerd/containerd.sock \
# 设置镜像拉取的仓库地址，采用阿里云镜像
--image-repository=registry.aliyuncs.com/google_containers
成功之后，会有如下输出：
Your Kubernetes control-plane has initialized successfully!
To start using your cluster, you need to run the following as a regular user:
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
Alternatively, if you are the root user, you can run:
export KUBECONFIG=/etc/kubernetes/admin.conf
You should now deploy a pod network to the cluster.
Run "kubectl apply -f [podnetwork].yaml" with one of the options listed at:
https://kubernetes.io/docs/concepts/cluster-administration/addons/
You can now join any number of control-plane nodes by copying certificate authorities
and service account keys on each node and then running the following as root:
kubeadm join <control-plane-host>:<control-plane-port> --token <token> \
--discovery-token-ca-cert-hash sha256:<hash> \
--control-plane
Then you can join any number of worker nodes by running the following on each as root:
kubeadm join <control-plane-host>:<control-plane-port> --token <token> \
--discovery-token-ca-cert-hash sha256:<hash>
2. 配置 kubectl 的配置文件
$ mkdir -p $HOME/.kube
$ sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
$ sudo chown $(id -u):$(id -g) $HOME/.kube/config
3. 子节点创建
子节点也需要安装 kubelet kubeadm kubectl。
重复上面的安装步骤即可。
4. 子节点加入控制平面节点
sudo kubeadm join <control-plane-host>:<control-plane-port> --token <token> --discovery-token-ca-cert-hash sha256:<hash> --cri-socket=unix:/run/containerd/containerd.sock
成功之后，会有如下输出：
This node has joined the cluster:
* Certificate signing request was sent to apiserver and a response was received.
* The Kubelet was informed of the new secure connection details.
Run 'kubectl get nodes' on the control-plane to see this node join the cluster.
四、安装 Pod 网络附加组件
集群已经搭建起来了，然后我们会发现 coredns 停滞在 Pending 状态。
还记得我们在初始化控制平面时，传的--pod-network-cidr=10.244.0.0/16参数么？
就是为这一步准备的，让我们开始吧。
1. 安装 flannel
点击下载 最新的稳定版本 。
下载完成后，确保每个服务器的 /opt/bin 文件夹内都有 flanneld 二进制文件。
2. 启动 flannel
kubectl apply -f https://raw.githubusercontent.com/flannel-io/flannel/master/Documentation/kube-flannel.yml
