Docker镜像的基本操作

获取镜像

Usage:  docker pull [OPTIONS] NAME[:TAG|@DIGEST]
docker pull hello-world

localhost:my_test sukangshen$ docker pull hello-world
Using default tag: latest
latest: Pulling from library/hello-world
1b930d010525: Pull complete
Digest: sha256:0e11c388b664df8a27a901dce21eb89f11d8292f7fca1b3e3c4321bf7897bffe
Status: Downloaded newer image for hello-world:latest
localhost:my_test sukangshen$

查看镜像列表

Usage:  docker images [OPTIONS] [REPOSITORY[:TAG]]
docker images

REPOSITORY                     TAG                 IMAGE ID            CREATED             SIZE
<none>                         <none>              599e3b0290cd        4 days ago          421MB
<none>                         <none>              6998f5aabe68        5 days ago          484MB
<none>                         <none>              12f997a68afb        5 days ago          484MB
<none>                         <none>              4f229677daca        6 days ago          484MB
<none>                         <none>              f6ed0b7852c5        6 days ago          484MB
<none>                         <none>              39c63c52fc6a        6 days ago          484MB
dnmp_php72                     latest              1a5f62f4795f        4 weeks ago         611MB
hello-world         latest              fce289e99eb9        4 months ago        1.84kB

虚悬镜像

上面的镜像列表中，还可以看到一个特殊的镜像，这个镜像既没有仓库名，也没有标签，均为 <none>。：

<none>                         <none>              4f229677daca        6 days ago          484MB

这个镜像原本是有镜像名和标签的，原来为 mongo:3.2，随着官方镜像维护，发布了新版本后，重新 docker pull mongo:3.2 时，mongo:3.2 这个镜像名被转移到了新下载的镜像身上，而旧的镜像上的这个名称则被取消，从而成为了 <none>。除了 docker pull 可能导致这种情况，docker build 也同样可以导致这种现象。由于新旧镜像同名，旧镜像名称被取消，从而出现仓库名、标签均为 <none> 的镜像。这类无标签镜像也被称为 虚悬镜像(dangling image) ，可以用下面的命令专门显示这类镜像：

docker image ls -f dangling=true
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
<none>              <none>              00285df0df87        5 days ago          342 MB

一般来说，虚悬镜像已经失去了存在的价值，是可以随意删除的，可以用下面的命令删除。

docker image prune

中间层镜像

为了加速镜像构建、重复利用资源，Docker 会利用 中间层镜像。所以在使用一段时间后，可能会看到一些依赖的中间层镜像。默认的 docker image ls 列表中只会显示顶层镜像，如果希望显示包括中间层镜像在内的所有镜像的话，需要加 -a 参数。

 docker image ls -a

这样会看到很多无标签的镜像，与之前的虚悬镜像不同，这些无标签的镜像很多都是中间层镜像，是其它镜像所依赖的镜像。这些无标签镜像不应该删除，否则会导致上层镜像因为依赖丢失而出错。实际上，这些镜像也没必要删除，因为之前说过，相同的层只会存一遍，而这些镜像是别的镜像的依赖，因此并不会因为它们被列出来而多存了一份，无论如何你也会需要它们。只要删除那些依赖它们的镜像后，这些依赖的中间层镜像也会被连带删除。

查看镜像信息

Usage:  docker inspect [OPTIONS] NAME|ID [NAME|ID...]
docker inspect hello-world

localhost:my_test sukangshen$ docker inspect hello-world
[
    {
        "Id": "sha256:fce289e99eb9bca977dae136fbe2a82b6b7d4c372474c9235adc1741675f587e",
        "RepoTags": [
            "hello-world:latest"
        ],
        "RepoDigests": [
            "hello-world@sha256:0e11c388b664df8a27a901dce21eb89f11d8292f7fca1b3e3c4321bf7897bffe"
        ],
        "Parent": "",
        "Comment": "",
        "Created": "2019-01-01T01:29:27.650294696Z",
        "Container": "8e2caa5a514bb6d8b4f2a2553e9067498d261a0fd83a96aeaaf303943dff6ff9",
        "ContainerConfig": {
            "Hostname": "8e2caa5a514b",
            "Domainname": "",
            "User": "",
            "AttachStdin": false,
            "AttachStdout": false,
            "AttachStderr": false,
            "Tty": false,
            "OpenStdin": false,
            "StdinOnce": false,
            "Env": [
                "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
            ],
            "Cmd": [
                "/bin/sh",
                "-c",
                "#(nop) ",
                "CMD [\"/hello\"]"
            ],
            "ArgsEscaped": true,
            "Image": "sha256:a6d1aaad8ca65655449a26146699fe9d61240071f6992975be7e720f1cd42440",
            "Volumes": null,
            "WorkingDir": "",
            "Entrypoint": null,
            "OnBuild": null,
            "Labels": {}
        },
        "DockerVersion": "18.06.1-ce",
        "Author": "",
        "Config": {
            "Hostname": "",
            "Domainname": "",
            "User": "",
            "AttachStdin": false,
            "AttachStdout": false,
            "AttachStderr": false,
            "Tty": false,
            "OpenStdin": false,
            "StdinOnce": false,
            "Env": [
                "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
            ],
            "Cmd": [
                "/hello"
            ],
            "ArgsEscaped": true,
            "Image": "sha256:a6d1aaad8ca65655449a26146699fe9d61240071f6992975be7e720f1cd42440",
            "Volumes": null,
            "WorkingDir": "",
            "Entrypoint": null,
            "OnBuild": null,
            "Labels": null
        },
        "Architecture": "amd64",
        "Os": "linux",
        "Size": 1840,
        "VirtualSize": 1840,
        "GraphDriver": {
            "Data": {
                "MergedDir": "/var/lib/docker/overlay2/90fa938dbfd9549051616136abb31b97d883f81715b52ac31be844525dab0dc7/merged",
                "UpperDir": "/var/lib/docker/overlay2/90fa938dbfd9549051616136abb31b97d883f81715b52ac31be844525dab0dc7/diff",
                "WorkDir": "/var/lib/docker/overlay2/90fa938dbfd9549051616136abb31b97d883f81715b52ac31be844525dab0dc7/work"
            },
            "Name": "overlay2"
        },
        "RootFS": {
            "Type": "layers",
            "Layers": [
                "sha256:af0b15c8625bb1938f1d7b17081031f649fd14e6b233688eea3c5483994a66a3"
            ]
        },
        "Metadata": {
            "LastTagTime": "0001-01-01T00:00:00Z"
        }
    }
]
localhost:my_test sukangshen$

查找镜像

Usage:  docker search [OPTIONS] TERM
docker search hello-world

使用docker search命令可以搜索远端仓库中共享的镜像，默认搜索Docker hub官方仓库中的镜像。

localhost:my_test sukangshen$ docker search hello-world
NAME                                       DESCRIPTION                                     STARS               OFFICIAL            AUTOMATED
hello-world                                Hello World! (an example of minimal Dockeriz…   929                 [OK]
kitematic/hello-world-nginx                A light-weight nginx container that demonstr…   124
tutum/hello-world                          Image to test docker deployments. Has Apache…   60                                      [OK]
dockercloud/hello-world                    Hello World!                                    15                                      [OK]
crccheck/hello-world                       Hello World web server in under 2.5 MB          6                                       [OK]
ppc64le/hello-world                        Hello World! (an example of minimal Dockeriz…   2
markmnei/hello-world-java-docker           Hello-World-Java-docker                         1                                       [OK]
souravpatnaik/hello-world-go               hello-world in Golang                           1
carinamarina/hello-world-app               This is a sample Python web application, run…   1                                       [OK]
kevindockercompany/hello-world                                                             0
koudaiii/hello-world                                                                       0
burdz/hello-world-k8s                      To provide a simple webserver that can have …   0                                       [OK]
infrastructureascode/hello-world           A tiny "Hello World" web server with a healt…   0                                       [OK]
ansibleplaybookbundle/hello-world-db-apb   An APB which deploys a sample Hello World! a…   0                                       [OK]
uniplaces/hello-world                                                                      0
ansibleplaybookbundle/hello-world          Simple containerized application that tests …   0
nirmata/hello-world                                                                        0                                       [OK]
ansibleplaybookbundle/hello-world-apb      An APB which deploys a sample Hello World! a…   0                                       [OK]
stumacsolutions/hello-world-container                                                      0
mbrainar/hello-world                       Python-based hello-world web service            0
sharor/hello-world                                                                         0
kousik93/hello-world                                                                       0
ebenjaminv9/hello-world                    Hello-world                                     0
s390x/hello-world                          Hello World! (an example of minimal Dockeriz…   0
jensendw/hello-world                                                                       0
localhost:my_test sukangshen$

删除镜像

使用docker rmi命令可以删除镜像，其中image可以为标签或ID。

Usage:  docker rmi [OPTIONS] IMAGE [IMAGE...]
docker rmi hello-world

localhost:my_test sukangshen$ docker rmi hello-world
Untagged: hello-world:latest
Untagged: hello-world@sha256:0e11c388b664df8a27a901dce21eb89f11d8292f7fca1b3e3c4321bf7897bffe
Deleted: sha256:fce289e99eb9bca977dae136fbe2a82b6b7d4c372474c9235adc1741675f587e
Deleted: sha256:af0b15c8625bb1938f1d7b17081031f649fd14e6b233688eea3c5483994a66a3
localhost:my_test sukangshen$

注意：
当同一个镜像拥有多个标签，docker rmi只是删除该镜像多个标签中的指定标签而已，而不影响镜像文件。
当有该镜像创建的容器存在时，镜像文件默认是无法被删除的。
如果一个镜像就有一个tag的话，删除tag就删除了镜像的本身。

停止、删除所有的docker容器和镜像

列出所有的容器 ID

docker ps -aq

停止所有的容器

docker stop $(docker ps -aq)

删除所有的容器

docker rm $(docker ps -aq)

删除所有的镜像

docker rmi $(docker images -q)