containerd客户端工具nerdctl的使用
kubernetes发布v1.20时宣布将弃用docker，并且在2021年下半年发布的v1.23版本中，彻底移除dockershim 代码，意味着那时kubernetes支持的容器运行时不再包括docker，那么我们使用containerd作为runtime。
docker命令大家非常熟悉且好用，但containerd的客户端工具ctr及crictl却是极其难用，给大家带来了诸多不变。本文主要讲containerd 全新的一个客户端工具nerdctl的使用。
步骤1：安装containerd
[root@vms101 ~]# yum install containerd.io cri-tools -y
...大量输出...
作为依赖被升级:
audit.x86_64 0:2.8.5-4.el7 audit-libs.x86_64 0:2.8.5-4.el7
libselinux.x86_64 0:2.5-15.el7 libselinux-python.x86_64 0:2.5-15.el7
libselinux-utils.x86_64 0:2.5-15.el7 libsemanage.x86_64 0:2.5-14.el7
libsepol.x86_64 0:2.5-10.el7 policycoreutils.x86_64 0:2.5-34.el7
selinux-policy.noarch 0:3.13.1-268.el7_9.2
完毕！
[root@vms101 ~]#
步骤2：启动containerd并设置开机自动启动
[root@vms101 ~]# systemctl enable containerd --now
Created symlink from /etc/systemd/system/multi-user.target.wants/containerd.service to /usr/lib/systemd/system/containerd.service.
[root@vms101 ~]#
步骤3：修改containerd配置文件并配置加速器
[root@vms101 ~]# cat /etc/containerd/config.toml
disabled_plugins = ["restart"]
[plugins]
[plugins.cri.registry.mirrors."docker.io"]
endpoint = ["https://frz7i079.mirror.aliyuncs.com"]
[root@vms101 ~]#
步骤4：重启containerd
重启containerd
[root@vms101 ~]# systemctl restart containerd
[root@vms101 ~]#
步骤5：下载并安装nerdctl
https://github.com/containerd/nerdctl/releases
下载最新版本的nerdctl
解压到/usr/local/bin里：
[root@vms101 ~]# tar zxvf nerdctl-0.8.0-linux-amd64.tar.gz -C /usr/local/bin/
nerdctl
containerd-rootless-setuptool.sh
containerd-rootless.sh
[root@vms101 ~]# ls /usr/local/bin/
containerd-rootless-setuptool.sh containerd-rootless.sh nerdctl
[root@vms101 ~]#
步骤6：安装网络插件
到https://github.com/containernetworking/plugins/releases下载最新版本CNI插件，解压放在/opt/cni/bin目录中。
[root@vms101 ~]# mkdir -p /opt/cni/bin/
[root@vms101 ~]# tar zxf cni-plugins-linux-amd64-v0.9.1.tgz -C /opt/cni/bin/
[root@vms101 ~]#
步骤7：设置nerdctl子命令可以使用tab键
在/etc/profile里添加source <(nerdctl completion bash)，如下：
[root@vms101 ~]# head -2 /etc/profile
# /etc/profile
source <(nerdctl completion bash)
[root@vms101 ~]#
让设置生效：
[root@vms101 ~]# source /etc/profile
[root@vms101 ~]#
步骤8：镜像管理
[root@vms101 ~]# nerdctl pull nginx #拉取镜像
docker.io/library/nginx:latest: resolved |++++++++++++++++++++++++++++++++++++++|
index-sha256:75a55d33ecc73c2a242450a9f1cc858499d468f077ea942867e662c247b5e412: done |++++++++++++++++++++++++++++++++++++++|
...大量输出...
done |++++++++++++++++++++++++++++++++++++++|
layer-sha256:aa1efa14b3bfc78fab92952a716bb9d6bda5de150727297dbd8bda66c933a0f3: done |++++++++++++++++++++++++++++++++++++++|
elapsed: 47.7s total: 51.2 M (1.1 MiB/s)
[root@vms101 ~]#
[root@vms101 ~]# nerdctl images
REPOSITORY TAG IMAGE ID CREATED SIZE
nginx latest 75a55d33ecc7 About a minute ago 51.2 MiB
[root@vms101 ~]#
给nginx镜像做标签为192.168.26.101/cka/nginx:v1
[root@vms101 ~]# nerdctl tag docker.io/library/nginx:latest 192.168.26.101/cka/nginx:v1
[root@vms101 ~]# nerdctl images
REPOSITORY TAG IMAGE ID CREATED SIZE
192.168.26.101/cka/nginx v1 75a55d33ecc7 1 second ago 51.2 MiB
nginx latest 75a55d33ecc7 About a minute ago 51.2 MiB
[root@vms101 ~]#
步骤9：创建容器
[root@vms101 ~]# nerdctl run -d --name=c1 --restart=always -p 80:80 192.168.26.101/cka/nginx:v1
9ba001a932043d9e15c67ed610dfe2255b80926bf5a77f372d6183512b1e73be
[root@vms101 ~]#
[root@vms101 ~]# nerdctl ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
9ba001a93204 192.168.26.101/cka/nginx:v1 "/docker-entrypoint.…" 5 seconds ago Up 0.0.0.0:80->80/tcp c1
[root@vms101 ~]#
在物理机上访问此容器
步骤10：容器管理
[root@vms101 ~]# nerdctl exec -it c1 bash
root@9ba001a93204:/# exit
exit
[root@vms101 ~]#
