ubuntu 安装 Kubernetes

部署架构

环境准备

1. 安装运行时环境，步骤省略

   k8s 支持一下容器运行环境

   • containerd
   • CRI-O
   • Docker Engine（推荐）
   • Mirantis Container Runtime

2. 设置 hostname

   sudo hostnamectl set-hostname k8s-master1 # master 节点执行
   sudo hostnamectl set-hostname k8s-node1 # node 节点执行
   sudo hostnamectl set-hostname k8s-node2 # node 节点执行

3. 配置 hosts

   cat << EOF | sudo tee -a /etc/hosts 
   
   192.168.1.200 k8s-master1
   192.168.1.10 k8s-node1
   192.168.1.121 k8s-node2
   
   EOF

4. 禁用 swap

   sudo swapoff -a
   sudo sed -i '/ swap / s/^\(.*\)$/#\1/g' /etc/fstab

5. 加载内核模块

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

   lsmod | grep br_netfilter 命令可以验证 br_netfilter 模块是否已加载

6. 网桥设置

   # 设置所需的 sysctl 参数，参数在重新启动后保持不变
   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 参数而不重新启动
   sudo sysctl --system

7. systemd cgroup 驱动配置

   # 生成默认配置
   containerd config default | sudo tee /etc/containerd/config.toml >/dev/null 2>&1
   # 修改 cgroup 为 systemd
   sudo sed -i 's/SystemdCgroup \= false/SystemdCgroup \= true/g' /etc/containerd/config.toml

8. 重启容器运行环境

   sudo systemctl restart containerd

安装

安装 kubeadm

sudo apt-get update
sudo apt-get install -y apt-transport-https ca-certificates curl
# 下载 Google Cloud 公开签名秘钥：
sudo curl -fsSLo /usr/share/keyrings/kubernetes-archive-keyring.gpg https://packages.cloud.google.com/apt/doc/apt-key.gpg
# 添加 Kubernetes apt 仓库
echo "deb [signed-by=/usr/share/keyrings/kubernetes-archive-keyring.gpg] https://apt.kubernetes.io/ kubernetes-xenial main" | sudo tee /etc/apt/sources.list.d/kubernetes.list
# 安装 kubelet、kubeadm 和 kubectl，并锁定其版本
sudo apt-get update
sudo apt-get install -y kubelet kubeadm kubectl
sudo apt-mark hold kubelet kubeadm kubectl

部署 master

# 修改为对应 master ip
# pod-network-cidr 是对应 pod ip 段
sudo kubeadm init --kubernetes-version=1.25.0 --apiserver-advertise-address=192.168.1.200 --service-cidr=10.96.0.0/12 --pod-network-cidr=10.244.0.0/16 --image-repository registry.aliyuncs.com/google_containers

执行成功会出现以下内容

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/

Then you can join any number of worker nodes by running the following on each as root:

kubeadm join 192.168.1.200:6443 --token 9s6kq5.0r2yj3bpzy7an0um \
    --discovery-token-ca-cert-hash sha256:62c0d12c44e2ccccc734a1429c04a24f7e28e4f40b3b5351d24d3e4e9981c0a9

拷贝配置文件到普通用户目录，方便使用普通用户管理不需要 sudo 执行

mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config

安装网络插件

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

部署 node

Then you can join any number of worker nodes by running the following on each as root:

sudo kubeadm join 192.168.1.200:6443 --token 9s6kq5.0r2yj3bpzy7an0um \
    --discovery-token-ca-cert-hash sha256:62c0d12c44e2ccccc734a1429c04a24f7e28e4f40b3b5351d24d3e4e9981c0a9 --v=5

测试

# 查看 node 状态，Ready 表示正常
kubectl get nodes
NAME          STATUS   ROLES           AGE   VERSION
k8s-master1   Ready    control-plane   11h   v1.25.0
k8s-node1     Ready    <none>          10h   v1.25.0
k8s-node2     Ready    <none>          62m   v1.25.0

部署 nginx（在 master 执行）

kubectl create deployment my-nginx --image=nginx
# 暴露 nginx 端口
kubectl expose deployment nginx-app --type=NodePort --port=80
# 查看服务状态，找到 PORT(S) 对应的端口
kubectl get svc my-nginx
NAME       TYPE       CLUSTER-IP      EXTERNAL-IP   PORT(S)        AGE
my-nginx   NodePort   10.111.141.52   <none>        80:30681/TCP   11m

通过 PORT(S) 对应的端口使用任意 node 公网（局域网）ip 测试访问是否正常

curl http://192.168.1.121:30681

删除实例

kubectl delete deployment my-nginx

常见问题

• 安装后启动失败，可以使用 journalctl -f -u kubelet 查看日志

参考

• 容器运行时
• 安装 kubeadm
• 命令行工具 (kubectl)