简介

kubernetes 1.24.0以上版本已经移除了docker cri,因此在使用的docker来的安装k8s时,你需要自己安装cri-docker

名词解释

  • cri:容器运行时,这个东东是用来在pod中控制容器的

服务器最低配置要求

  • cpu:2核心
  • 内存:2G

服务器上设置

  • 关闭swap
  • 关闭firewalld
  • 禁用selinux
  • 启用br_netfilter模块
  • 6443端口

必要服务

  • docker 每个节点必须
  • iptables 每个节点必须
  • cri-docker 每个节点必须:注意:启动服务时需要指定–pod-infra-container-image选项,否则可能导致初始化失败
  • kubelet 每个节点必须
  • kubeadm 每个节点必须
  • kubectl 按需安装,用来的与集群交互

服务器初始化

以下为ansible的剧本,cri-docker.service设置部分没写,自己搞搞

---
- hosts: localhost
  remote_user: root
  tasks:
   - name: 关闭firewalld并且取消开机启动
     systemd:
      enabled: FALSE
      state: stopped
      name: firewalld.service

   - name: 永久关闭selinux
     lineinfile:
      dest: /etc/selinux/config
      regexp: "^SELINUX="
      line: "SELINUX=disabled"

   - name: 临时关闭selinux
     shell: "setenforce 0"
     failed_when: FALSE

   - name: 关闭swap
     shell: "swapoff -a && sed -i 's/^[^#]*swap/#&/g' /etc/fstab"

   - name: 安装yum-utils
     yum: name=yum-utils state=present

   - name: 添加docker-ce repo文件
     shell: yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo

   - name: 安装docker
     shell: yum install docker-ce -y

   - name: 创建/root/cri目录
     file:
       state: directory
       path: /root/cri

   - name: 拷贝cri-docker rpm包
     copy:
      src: /root/cri/cri-dockerd-0.2.5-3.el7.x86_64.rpm
      dest: /root/cri/cri-dockerd-0.2.5-3.el7.x86_64.rpm

   - name: 安装cri-docker
     shell: rpm -ivh /root/cri/cri-dockerd-0.2.5-3.el7.x86_64.rpm 
  
   - name: 创建k8s.config文件
     shell:
      cmd: |
       cat <<EOF | sudo tee /etc/modules-load.d/k8s.conf
       overlay
       br_netfilter
       EOF

   - name: 安装overlay模块
     shell: sudo modprobe overlay

   - name: 安装br_netfilter模块
     shell: sudo modprobe br_netfilter

   - name: 设置所需的 sysctl参数,参数在重新启动后保持不变
     shell:
      cmd: |
        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

   - name: 应用 sysctl 参数而不重新启动
     shell: sudo sysctl --system
   - name: 创建k8s.config文件 
     shell:
      cmd: |
       cat <<EOF | sudo tee /etc/modules-load.d/k8s.conf
       overlay
       br_netfilter
       EOF

   - name: 安装overlay模块
     shell: sudo modprobe overlay

   - name: 安装br_netfilter模块
     shell: sudo modprobe br_netfilter

   - name: 设置所需的 sysctl参数,参数在重新启动后保持不变
     shell:
      cmd: |
        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

   - name: 应用 sysctl 参数而不重新启动
     shell: sudo sysctl --system

cri-docker rpm包下载地址

https://github.com/Mirantis/cri-dockerd/releases/tag/v0.2.5

kubeadm 初始化文件init.yaml

此文件可命令kubeadm config print init-defaults生成,生产以后按自己实际情况修改文件,不要抄!

apiVersion: kubeadm.k8s.io/v1beta3
bootstrapTokens:
- groups:
  - system:bootstrappers:kubeadm:default-node-token
  token: abcdef.0123456789abcdef
  ttl: 24h0m0s
  usages:
  - signing
  - authentication
kind: InitConfiguration
localAPIEndpoint:
  advertiseAddress: 192.168.100.101  #改成你自己的IP地址
  bindPort: 6443
nodeRegistration:
  criSocket: unix:///run/cri-dockerd.sock #改成这个套接字
  imagePullPolicy: IfNotPresent
  name: master01  #改成你自己的主机名
  taints: null
---
apiServer:
  timeoutForControlPlane: 4m0s
apiVersion: kubeadm.k8s.io/v1beta3
certificatesDir: /etc/kubernetes/pki
clusterName: kubernetes
controllerManager: {}
dns: {}
etcd:
  local:
    dataDir: /var/lib/etcd
imageRepository: registry.aliyuncs.com/google_containers
kind: ClusterConfiguration
kubernetesVersion: 1.24.3
networking:
  dnsDomain: cluster.local
  serviceSubnet: 10.96.0.0/12
scheduler: {}

拉取必要镜像

kubeadm config images list命令可以查看1.24.3版本需要的镜像文件
国内仓库:registry.aliyuncs.com/google_containers
注意:etcd在registry.aliyuncs.com/google_containers仓库中可能找不到,可以上dockerhub上找找

[root@master01 ~]# kubeadm config images list
k8s.gcr.io/kube-apiserver:v1.24.3
k8s.gcr.io/kube-controller-manager:v1.24.3
k8s.gcr.io/kube-scheduler:v1.24.3
k8s.gcr.io/kube-proxy:v1.24.3
k8s.gcr.io/pause:3.7
k8s.gcr.io/etcd:3.5.3-0
k8s.gcr.io/coredns/coredns:v1.8.6

拉取指定仓库的镜像

kubeadm config images pull --image-repository="registry.aliyuncs.com/google_containers" --cri-socket="unix:///run/cri-dockerd.sock"

注意事项

安装好cri-docker 以后,直接kubeadm init --config init.yaml 会提示超时,查看kubelet日志会提示找不到节点
这时,你需要配置cri-docker.service文件,ExecStart=/usr/bin/cri-dockerd项后面指定你的指定你的pause版本,
例如:–pod-infra-container-image=registry.aliyuncs.com/google_containers/pause:3.7
错误如下

Error getting node" err="node \"master01\" not found

解决方法

[root@master01 ansible]# cat /usr/lib/systemd/system/cri-docker.service 
[Unit]
Description=CRI Interface for Docker Application Container Engine
Documentation=https://docs.mirantis.com
After=network-online.target firewalld.service docker.service
Wants=network-online.target
Requires=cri-docker.socket

[Service]
Type=notify
ExecStart=/usr/bin/cri-dockerd --pod-infra-container-image=registry.aliyuncs.com/google_containers/pause:3.7 --container-runtime-endpoint fd://
ExecReload=/bin/kill -s HUP $MAINPID
TimeoutSec=0
RestartSec=2
Restart=always

# Note that StartLimit* options were moved from "Service" to "Unit" in systemd 229.
# Both the old, and new location are accepted by systemd 229 and up, so using the old location
# to make them work for either version of systemd.
StartLimitBurst=3

# Note that StartLimitInterval was renamed to StartLimitIntervalSec in systemd 230.
# Both the old, and new name are accepted by systemd 230 and up, so using the old name to make
# this option work for either version of systemd.
StartLimitInterval=60s

# Having non-zero Limit*s causes performance problems due to accounting overhead
# in the kernel. We recommend using cgroups to do container-local accounting.
LimitNOFILE=infinity
LimitNPROC=infinity
LimitCORE=infinity

# Comment TasksMax if your systemd version does not support it.
# Only systemd 226 and above support this option.
TasksMax=infinity
Delegate=yes
KillMode=process

[Install]
WantedBy=multi-user.target

完成后重启cri-service服务

[root@master01 ~]# systemctl daemon-reload && systemctl restart cri-docker.service

此时在此运算kubeadm init 就能成功初始化集群

reset集群

与以往不同的是需要指定一下cri-socket

[root@master01 ~]# kubeadm reset --cri-socket="unix:///run/cri-dockerd.sock" --v=5

tmux

拉取镜像时需要很长时间,避免长时间不操作导致远程断开,你可以在tmux中执行,非常好用的小工具,建议安装
文档

部署CNI

可选CNI方案有如下几种

$ kubectl apply -f "https://cloud.weave.works/k8s/net?k8s-version=$(kubectl version | base64 | tr -d '\n')"
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