更换k8s容器运行时环境为docker

k8s-V1.24之后容器运行时默认是containerd，若想改为熟悉的docker作为运行时，需要做以下操作

1. 在每个节点安装containerd、docker;

2. 每个节点安装cri-docker；

3. 调整kubelet配置并重启验证。

1.安装docker、containerd服务

# 安装docker和containerd
# 二进制包下载地址：https://download.docker.com/linux/static/stable/x86_64/
# wget https://download.docker.com/linux/static/stable/x86_64/docker-24.0.2.tgz
​
#解压
tar xf docker-*.tgz 
#拷贝二进制文件
cp docker/* /usr/bin/
#创建containerd的service文件,并且启动
cat >/etc/systemd/system/containerd.service <<EOF
[Unit]
Description=containerd container runtime
Documentation=https://containerd.io
After=network.target local-fs.target
​
[Service]
ExecStartPre=-/sbin/modprobe overlay
ExecStart=/usr/bin/containerd
Type=notify
Delegate=yes
KillMode=process
Restart=always
RestartSec=5
LimitNPROC=infinity
LimitCORE=infinity
LimitNOFILE=1048576
TasksMax=infinity
OOMScoreAdjust=-999
​
[Install]
WantedBy=multi-user.target
EOF
​
# 设置开机自启
systemctl enable --now containerd.service
systemctl status containerd.service
​
#准备docker的service文件
cat > /etc/systemd/system/docker.service <<EOF
[Unit]
Description=Docker Application Container Engine
Documentation=https://docs.docker.com
After=network-online.target firewalld.service docker.socket containerd.service
Wants=network-online.target
Requires=docker.socket containerd.service
​
[Service]
Type=notify
ExecStart=/usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock
ExecReload=/bin/kill -s HUP $MAINPID
TimeoutSec=0
RestartSec=2
Restart=always
StartLimitBurst=3
StartLimitInterval=60s
LimitNOFILE=infinity
LimitNPROC=infinity
LimitCORE=infinity
TasksMax=infinity
Delegate=yes
KillMode=process
OOMScoreAdjust=-500
​
[Install]
WantedBy=multi-user.target
EOF
​
​
#准备docker的socket文件
cat > /etc/systemd/system/docker.socket <<EOF
[Unit]
Description=Docker Socket for the API
​
[Socket]
ListenStream=/var/run/docker.sock
SocketMode=0660
SocketUser=root
SocketGroup=docker
​
[Install]
WantedBy=sockets.target
EOF
​
​
#创建docker组
groupadd docker
#启动docker
systemctl enable --now docker.socket  && systemctl enable --now docker.service
#验证
docker info
​
# 配置加速器
mkdir /etc/docker/ -pv
cat >/etc/docker/daemon.json <<EOF
{
  "exec-opts": ["native.cgroupdriver=systemd"],
  "registry-mirrors": [
    "https://docker.m.daocloud.io",
    "https://docker.mirrors.ustc.edu.cn",
    "http://hub-mirror.c.163.com"
  ],
  "max-concurrent-downloads": 10,
  "log-driver": "json-file",
  "log-level": "warn",
  "log-opts": {
    "max-size": "10m",
    "max-file": "3"
    },
  "data-root": "/var/lib/docker"
}
EOF
systemctl daemon-reload 
systemctl stop docker
systemctl restart docker

2.安装cri-docker

# 由于1.24以及更高版本不支持docker所以安装cri-docker,kubelet可以通过cri-docker间接编排容器
# 下载cri-docker 
# wget  https://mirrors.chenby.cn/https://github.com/Mirantis/cri-dockerd/releases/download/v0.3.3/cri-dockerd-0.3.3.amd64.tgz
​
# 解压cri-docker
tar xvf cri-dockerd-*.amd64.tgz 
cp -r cri-dockerd/  /usr/bin/
chmod +x /usr/bin/cri-dockerd/cri-dockerd
​
# 写入启动配置文件
cat >  /usr/lib/systemd/system/cri-docker.service <<EOF
[Unit]
Description=CRI Interface for Docker Application Container Engine
Documentation=https://docs.mirantis.com
After=network-online.target firewalld.service
Wants=network-online.target
Requires=cri-docker.socket
​
[Service]
Type=notify
ExecStart=/usr/bin/cri-dockerd/cri-dockerd --network-plugin=cni --pod-infra-container-image=registry.aliyuncs.com/google_containers/pause:3.7
ExecReload=/bin/kill -s HUP $MAINPID
TimeoutSec=0
RestartSec=2
Restart=always
​
StartLimitBurst=3
StartLimitInterval=60s
​
LimitNOFILE=infinity
LimitNPROC=infinity
LimitCORE=infinity
​
TasksMax=infinity
Delegate=yes
KillMode=process
​
[Install]
WantedBy=multi-user.target
EOF
​
# 写入socket配置文件
cat > /usr/lib/systemd/system/cri-docker.socket <<EOF
[Unit]
Description=CRI Docker Socket for the API
PartOf=cri-docker.service
​
[Socket]
ListenStream=%t/cri-dockerd.sock
SocketMode=0660
SocketUser=root
SocketGroup=docker
​
[Install]
WantedBy=sockets.target
EOF
​
# 进行启动cri-docker
systemctl daemon-reload 
systemctl enable cri-docker --now
systemctl restart cri-docker
systemctl status cri-docker

3.调整kubelet配置，并重启验证

#注释掉原来的配置，改为：--container-runtime-endpoint=unix:///run/cri-dockerd.sock \
cat /etc/systemd/system/kubelet.service
[Unit]
Description=Kubernetes Kubelet
Documentation=https://github.com/GoogleCloudPlatform/kubernetes
​
[Service]
WorkingDirectory=/var/lib/kubelet
ExecStartPre=/bin/mount -o remount,rw '/sys/fs/cgroup'
ExecStart=/opt/kube/bin/kubelet \
  --config=/var/lib/kubelet/config.yaml \
#  --container-runtime-endpoint=unix:///run/containerd/containerd.sock \
  --container-runtime-endpoint=unix:///run/cri-dockerd.sock \
  --hostname-override=10.10.10.3 \
  --kubeconfig=/etc/kubernetes/kubelet.kubeconfig \
  --root-dir=/var/lib/kubelet \
  --v=2
Restart=always
RestartSec=5
​
[Install]
WantedBy=multi-user.target
​
systemctl daemon-reload
systemctl restart kubelet
​
# 验证：
[root@10-3 down]# kubectl get node -owide
NAME         STATUS   ROLES    AGE   VERSION    INTERNAL-IP   EXTERNAL-IP   OS-IMAGE                    KERNEL-VERSION                       CONTAINER-RUNTIME
10.10.10.3   Ready    master   26h   v1.27.16   10.10.10.3    <none>        openEuler 22.03 (LTS-SP3)   5.10.0-182.0.0.95.oe2203sp3.x86_64   docker://24.0.5
k8s-node01   Ready    node     8h    v1.27.16   10.10.10.4    <none>        openEuler 22.03 (LTS-SP3)   5.10.0-182.0.0.95.oe2203sp3.x86_64   docker://24.0.5

#删除节点上的历史容器
crictl rm -f `crictl ps -aq`