Containerd-1.6.5 镜像容器操作

阅读原文时间：2023年07月08日阅读：4

一、Containerd 镜像操作

1 基本参数

[root@ecs-65685 ~]# ctr c
NAME:
   ctr containers - manage containers

USAGE:
   ctr containers command [command options] [arguments...]

COMMANDS:
   create                   create container
   delete, del, remove, rm  delete one or more existing containers
   info                     get info about a container
   list, ls                 list containers
   label                    set and clear labels for a container
   checkpoint               checkpoint a container
   restore                  restore a container from checkpoint

OPTIONS:
   --help, -h  show help

2 镜像操作

在containerd中拉取docker的相关镜像也需要补全。

containerd支持oci标准的镜像，所以可以直接使用docker官方或dockerfile构建的镜像。

--platform 选项指定对应平台的镜像。当然对应的也有推送镜像的命令 ctr image push，如果是私有镜像则在推送的时候可以通过 --user 来自定义仓库的用户名和密码。

拉取镜像添加了--all-platforms会将所有平台都下载下来（amd64 、arm、386 、ppc64le ），否则默认下载当前平台。

拉取镜像可以使用 ctr image pull 来完成，比如拉取 Docker Hub 官方镜像 nginx:alpine，需要注意的是镜像地址需要加上 docker.io Host 地址。

 ctr i pull docker.io/library/nginx:alpine --all-platforms

3 查看镜像

查看镜像可以使用 i 或者image
-q 只打印镜像名称

ctr i ls
ctr i ls -q

4 检测本地镜像

[root@ecs-65685 ~]# ctr image check
REF                            TYPE                                                      DIGEST                                                                  STATUS         SIZE            UNPACKED
docker.io/library/nginx:alpine application/vnd.docker.distribution.manifest.list.v2+json sha256:b87c350e6c69e0dc7069093dcda226c4430f3836682af4f649f2af9e9b5f1c74 complete (7/7) 9.7 MiB/9.7 MiB true

主要查看其中的 STATUS，complete 表示镜像是完整可用的状态。

5 tag重新打标签

[root@ecs-65685 ~]# ctr i tag docker.io/library/nginx:alpine docker.io/library/nginx:nginxxyz
docker.io/library/nginx:nginxxyz
[root@ecs-65685 ~]# ctr i ls -q
docker.io/library/nginx:alpine
docker.io/library/nginx:nginxxyz # 新增tag

6 删除镜像

使用：delete, del, remove, rm remove one or more images by reference。都可以进行删除。

[root@ecs-65685 ~]# ctr i rm docker.io/library/nginx:nginxxyz
docker.io/library/nginx:nginxxyz
[root@ecs-65685 ~]# ctr i ls -q
docker.io/frps9/tools:SynologyNAS
docker.io/library/nginx:alpine

7 mount镜像

mount镜像实际上将镜像中的文件，挂载到宿主机的目录中去。

mount参数系统为只读状态，只可以读取，不可以写入数据。

使用--rw Enable write support on the mount 可以开启只读。

[root@ecs-65685 ~]# mkdir /home/xyz
[root@ecs-65685 ~]# ctr i ls -q
docker.io/library/nginx:alpine
[root@ecs-65685 ~]# ctr i mount  docker.io/library/nginx:alpine /home/xyz/
sha256:26bec62cc7fc1f93f810d51c3f51291dae2d0f9e192e054cc61d1914365003d8
/home/xyz/
[root@ecs-65685 ~]# ls /home/xyz
bin  docker-entrypoint.d   etc   lib    mnt  proc  run   srv  tmp  var
dev  docker-entrypoint.sh  home  media  opt  root  sbin  sys  usr

mount卸载

[root@ecs-65685 ~]# ctr i unmount /home/xyz
/home/xyz
[root@ecs-65685 ~]# ls /home/xyz

8 推送镜像

[root@ecs-65685 ~]# ctr i push -k docker.io/library/nginx:alpine
index-sha256:b87c350e6c69e0dc7069093dcda226c4430f3836682af4f649f2af9e9b5f1c74: waiting        |--------------------------------------|
elapsed: 0.1 s                                                                 total:   0.0 B (0.0 B/s)
ctr: content digest sha256:36f21d30317cff60a6ab8328cca93dbe554020ba0320c78e964040512d0f27a0: not found

跳过ssl验证--skip-verify， -k skip SSL certificate validation。

9 导入导出

import
export
默认export导出的为OCI tar，只要我们容器支持OCI，基本上都是可以使用的
同时导出可以使用--platform导出其它平台的(例如arm)
--all-platforms为导出所有平台

[root@ecs-65685 xyz]# ls
[root@ecs-65685 xyz]# ctr i ls -q
docker.io/library/nginx:alpine
[root@ecs-65685 xyz]# ctr i export --all-platforms nginx.tar docker.io/library/nginx:alpine
[root@ecs-65685 xyz]# ctr i export nginx_i4t.com.tar docker.io/library/nginx:alpine
[root@ecs-65685 xyz]# ls
nginx_i4t.com.tar nginx.tar
[root@ecs-65685 xyz]#
[root@ecs-65685 xyz]# ctr i rm docker.io/library/nginx:alpine
docker.io/library/nginx:alpine
[root@ecs-65685 xyz]# ctr i import nginx.tar
unpacking docker.io/library/nginx:alpine (sha256:b87c350e6c69e0dc7069093dcda226c4430f3836682af4f649f2af9e9b5f1c74)…done
[root@ecs-65685 xyz]# ctr i ls -q
docker.io/library/nginx:alpine

二、Containerd 容器操作

1 基本参数

[root@ecs-65685 ~]# ctr c create -h
NAME:
   ctr containers create - create container

USAGE:
   ctr containers create [command options] [flags] Image|RootFS CONTAINER [COMMAND] [ARG...]

OPTIONS:
   --snapshotter value               snapshotter name. Empty value stands for the default value. [$CONTAINERD_SNAPSHOTTER]
   --snapshotter-label value         labels added to the new snapshot for this container.
   --config value, -c value          path to the runtime-specific spec config file
   --cwd value                       specify the working directory of the process
   --env value                       specify additional container environment variables (e.g. FOO=bar)
   --env-file value                  specify additional container environment variables in a file(e.g. FOO=bar, one per line)
   --label value                     specify additional labels (e.g. foo=bar)
   --mount value                     specify additional container mount (e.g. type=bind,src=/tmp,dst=/host,options=rbind:ro)
   --net-host                        enable host networking for the container
   --privileged                      run privileged container
   --read-only                       set the containers filesystem as readonly
   --runtime value                   runtime name (default: "io.containerd.runc.v2")
   --runtime-config-path value       optional runtime config path
   --tty, -t                         allocate a TTY for the container
   --with-ns value                   specify existing Linux namespaces to join at container runtime (format '<nstype>:<path>')
   --pid-file value                  file path to write the task's pid
   --gpus value                      add gpus to the container
   --allow-new-privs                 turn off OCI spec's NoNewPrivileges feature flag
   --memory-limit value              memory limit (in bytes) for the container (default: 0)
   --device value                    file path to a device to add to the container; or a path to a directory tree of devices to add to the container
   --cap-add value                   add Linux capabilities (Set capabilities with 'CAP_' prefix)
   --cap-drop value                  drop Linux capabilities (Set capabilities with 'CAP_' prefix)
   --seccomp                         enable the default seccomp profile
   --seccomp-profile value           file path to custom seccomp profile. seccomp must be set to true, before using seccomp-profile
   --apparmor-default-profile value  enable AppArmor with the default profile with the specified name, e.g. "cri-containerd.apparmor.d"
   --apparmor-profile value          enable AppArmor with an existing custom profile
   --rdt-class value                 name of the RDT class to associate the container with. Specifies a Class of Service (CLOS) for cache and memory bandwidth management.
   --rootfs                          use custom rootfs that is not managed by containerd snapshotter
   --no-pivot                        disable use of pivot-root (linux only)
   --cpu-quota value                 Limit CPU CFS quota (default: -1)
   --cpu-period value                Limit CPU CFS period (default: 0)
   --rootfs-propagation value        set the propagation of the container rootfs

2 创建一个nginx容器

-n 指定命名空间
c 是简写 containers, c, container manage containers
create 创建容器
--net-host 使用宿主机网络
docker.io/xx/xxx:xxx 镜像地址
nginx 容器名称

ctr -n xyz c create --net-host docker.io/library/nginx:alpine nginx

3 查看容器列表

[root@ecs-65685 ~]# ctr -n xyz c ls
CONTAINER    IMAGE                             RUNTIME
nginx        docker.io/library/nginx:alpine    io.containerd.runc.v2
nginx1       docker.io/library/nginx:alpine    io.containerd.runc.v2

4 只获取容器名称

[root@ecs-65685 ~]# ctr -n xyz c ls -q
nginx
nginx1

5 通过info参数查看容器的相关信息（类似于 docker inspect 功能）

ctr -n xyz c info nginx|less

6 删除容器

[root@ecs-65685 ~]# ctr -n xyz c ls -q
nginx
nginx1
[root@ecs-65685 ~]# ctr -n xyz container rm nginx1
[root@ecs-65685 ~]# ctr -n xyz c ls -q
nginx

除了使用 rm 子命令之外也可以使用 delete 或者 del 删除容器。

三、报错

ctr export导出或者import导入提示：ctr: content digest sha256:xxxxx: not found。

[root@ecs-65685 ~]# ctr image export --all-platforms nginx.tar docker.io/library/nginx:alpine
ctr: content digest sha256:36f21d30317cff60a6ab8328cca93dbe554020ba0320c78e964040512d0f27a0: not found

2 现象：