Fix containerd config: use standard paths and socket

Replace non-standard /run/cri-containerd/ paths with official
/run/containerd/containerd.sock, simplify service setup to use
default containerd config generation, and add unix:// prefix
to CRI socket URIs per Kubernetes conventions.

14_kubernetes_setup/14.1_kubeadm.md

@@ -20,54 +20,25 @@ $ sudo yum install containerd.io
 
 ### 14.1.2 配置 containerd
 
-新建 `/etc/systemd/system/cri-containerd.service` 文件
+生成默认配置文件：
 
 ```bash
-[Unit]
-Description=containerd container runtime for kubernetes
-Documentation=https://containerd.io
-After=network.target local-fs.target
-
-[Service]
-ExecStartPre=-/sbin/modprobe overlay
-ExecStart=/usr/bin/containerd --config /etc/cri-containerd/config.toml
-
-Type=notify
-Delegate=yes
-KillMode=process
-Restart=always
-RestartSec=5
-
-## Having non-zero Limit*s causes performance problems due to accounting overhead
-
-## in the kernel. We recommend using cgroups to do container-local accounting.
-
-LimitNPROC=infinity
-LimitCORE=infinity
-LimitNOFILE=infinity
-
-## Comment TasksMax if your systemd version does not supports it.
-
-## Only systemd 226 and above support this version.
-
-TasksMax=infinity
-OOMScoreAdjust=-999
-
-[Install]
-WantedBy=multi-user.target
+$ sudo mkdir -p /etc/containerd
+$ containerd config default | sudo tee /etc/containerd/config.toml > /dev/null
 ```
-新建 `/etc/cri-containerd/config.toml` containerd 配置文件
+
+修改 `/etc/containerd/config.toml` 配置文件
 
 ```toml
 version = 2
 
 ## persistent data location
 
-root = "/var/lib/cri-containerd"
+root = "/var/lib/containerd"
 
 ## runtime state information
 
-state = "/run/cri-containerd"
+state = "/run/containerd"
 plugin_dir = ""
 disabled_plugins = []
 required_plugins = []
@@ -77,7 +48,7 @@ required_plugins = []
 oom_score = 0
 
 [grpc]
-  address = "/run/cri-containerd/cri-containerd.sock"
+  address = "/run/containerd/containerd.sock"
   tcp_address = ""
   tcp_tls_cert = ""
   tcp_tls_key = ""
@@ -204,7 +175,7 @@ oom_score = 0
       max_conf_num = 1
       conf_template = ""
     [plugins."io.containerd.grpc.v1.cri".registry]
-      config_path = "/etc/cri-containerd/certs.d"
+      config_path = "/etc/containerd/certs.d"
       [plugins."io.containerd.grpc.v1.cri".registry.headers]
         # Foo = ["bar"]
 
@@ -214,7 +185,7 @@ oom_score = 0
       tls_cert_file = ""
       tls_key_file = ""
   [plugins."io.containerd.internal.v1.opt"]
-    path = "/opt/cri-containerd"
+    path = "/opt/containerd"
   [plugins."io.containerd.internal.v1.restart"]
     interval = "10s"
   [plugins."io.containerd.metadata.v1.bolt"]
@@ -339,14 +310,14 @@ $ sudo systemctl daemon-reload
 #### master
 
 ```bash
-$ systemctl enable cri-containerd
+$ systemctl enable containerd
 
-$ systemctl start cri-containerd
+$ systemctl start containerd
 
 $ sudo kubeadm init \
       --image-repository registry.cn-hangzhou.aliyuncs.com/google_containers \
       --pod-network-cidr 10.244.0.0/16 \
-      --cri-socket /run/cri-containerd/cri-containerd.sock \
+      --cri-socket unix:///run/containerd/containerd.sock \
       --v 5 \
       --ignore-preflight-errors=all
 ```
@@ -386,14 +357,14 @@ kubeadm join 192.168.199.100:6443 --token cz81zt.orsy9gm9v649e5lf \
 在 **另一主机** 重复 **部署** 小节以前的步骤，安装配置好 kubelet。根据提示，加入到集群。
 
 ```bash
-$ systemctl enable cri-containerd
+$ systemctl enable containerd
 
-$ systemctl start cri-containerd
+$ systemctl start containerd
 
 $ kubeadm join 192.168.199.100:6443 \
     --token cz81zt.orsy9gm9v649e5lf \
     --discovery-token-ca-cert-hash sha256:5edb316fd0d8ea2792cba15cdf1c899a366f147aa03cba52d4e5c5884ad836fe \
-    --cri-socket /run/cri-containerd/cri-containerd.sock
+    --cri-socket unix:///run/containerd/containerd.sock
 ```
 
 ### 14.1.7 查看服务
@@ -401,7 +372,7 @@ $ kubeadm join 192.168.199.100:6443 \
 所有服务启动后，通过 `crictl` 查看本地实际运行的容器。这些服务大概分为三类：主节点服务、工作节点服务和其它服务。
 
 ```bash
-CONTAINER_RUNTIME_ENDPOINT=/run/cri-containerd/cri-containerd.sock crictl ps -a
+CONTAINER_RUNTIME_ENDPOINT=unix:///run/containerd/containerd.sock crictl ps -a
 ```
 
 #### 主节点服务