更换Containerd后，以往我们常用的docker命令也不再使用，取而代之的分别是crictl和ctr两个命令客户端。crictl是遵循CRI接口规范的一个命令行工具，通常用它来检查和管理kubelet节点上的容器运行时和镜像，ctr是containerd的一个客户端工具。

containerd 相比于docker , 多了namespace概念, 每个image和container 都会在各自的namespace下可见, 目前k8s会使用k8s.io 作为命名空间，crictl 使用命名空间 k8s.io 。crictl image list 等价于 ctr -n=k8s.io image list 。

Crictl / Containerd / Docker

Functions Crictl CLI Containerd CLI Docker CLI
Image List crictl images ctr image ls docker images
Image Export ctr image export app.tar weiyigeek.top/app:1.2.0 docker save -o app.tar app:1.2.0
Image Import ctr image import app.tar docker load -i app.tar
Image Pull crictl pull redis:latest ctr -n k8s.io images pull docker.io/library/redis:latest docker pull redis:latest
Image Push crictl push redis:latest ctr -n k8s.io images push docker.io/library/redis:latest docker push redis:latest
Image Tag Update ctr -n k8s.io images tag docker.io/library/redis:latest weiyigeek.top/redis:latest docker tag redis:latest weiyigeek.top/redis:latest
Image Delete crictl rmi redis:latest ctr -n k8s.io images rm docker.io/library/redis:latest docker rmi redis:latest
Container Create ctr -n k8s.io container create docker.io/library/redis:latest redis docker create –name redis redis:latest
Container Create Run ctr -n k8s.io run -d –env name=WeiyiGeek weiyigeek.top/app:1.2.0 app docker run -d –name app weiyigeek.top/app:1.2.0
Container List crictl ps ctr -n k8s.io container list docker ps
Container Start crictl start ctr -n k8s.io task start app docker start app
Container Pause ctr -n k8s.io task pause app docker pause app
Container Stop crictl stop ctr -n k8s.io task kill app docker stop app
Container Delete crictl rm ctr -n k8s.io container rm [-f] app docker rm [-f] app
Container Detail Inspect crictl inspect app ctr -n k8s.io c info app docker inspect app
Container Attach crictl attach ctr -n k8s.io task attach app docker attach app
Run cmd inside Container crictl exec -it app sh ctr -n k8s.io task exec -t exec-id pid app sh docker exec -it app sh
Container Status crictl stats ctr -n k8s.io task metric app docker top app
Container Log crictl logs ctr -n k8s.io event docker logs –tail 50 app
Copy files from Container 1 挂载本地磁盘/tmp/mymount到app容器：ctr -n k8s.io snapshot mounts /tmp/mymount app 2 从本地/tmp/mymount目录复制文件：cp /tmp/mymount/data ~/data 3 卸载/tmp/mymount目录：umount /tmp/mymount docker cp

镜像导出导入

从docker更换为crictl后，由于crictl 没有提供 save 和 load 命令，如何存储和导入镜像呢？

1# ctr -n k8s.io image export busybox.tar.gz docker.io/library/busybox:latest
2# ctr -n k8s.io image import busybox.tar.gz

crictl官方文档

crictl配置使用