镜像
镜像的特点
- 文件和 meta data 集合
- 分层的，每层可添加和删除文件
- 不同 image 可以共享相同的 layer
- Image 本身是 read-only 的
最下层是 Linux Kernel(bootfs)，然后上面是 Base Image，如 Ubuntu, Centos (rootfs)，然后上面是一层一层的 Image。各种不同的 Base Image 会共享主机的 bootfs。
如果
搜索镜像
docker search [OPTIONS] TERM
--limit 限制最大条数，默认25
root@ubuntu:~# docker search nginx
NAME DESCRIPTION STARS OFFICIAL AUTOMATED
nginx Official build of Nginx. 16148 [OK]
jwilder/nginx-proxy Automated Nginx reverse proxy for docker con… 2108 [OK]
richarvey/nginx-php-fpm Container running Nginx + PHP-FPM capable of… 821 [OK]
- NAME 表示镜像仓库名称
- DIESCRIPTION 表示镜像仓库描述
- STARS 表示收藏数（受欢迎层度）
- OFFICAL 表示十分为官方镜像
- AUTOMATED 表示是否是自动构建镜像
拉取镜像
docker pull [OPTIONS] NAME[:TAG|@DIGEST]
例如
root@ubuntu:~# docker pull hello-world:latest
latest: Pulling from library/hello-world
2db29710123e: Pull complete
Digest: sha256:975f4b14f326b05db86e16de00144f9c12257553bba9484fed41f9b6f2257800
Status: Downloaded newer image for hello-world:latest
docker.io/library/hello-world:latest
显示镜像
docker image ls ，可以简写为 docker images
docker images [OPTIONS] [REPOSITORY[:TAG]]
例如
root@VM-4-17-ubuntu:~# docker image ls
REPOSITORY TAG IMAGE ID CREATED SIZE
node 14-slim cdcdba611ec1 5 weeks ago 168MB
nginx latest 87a94228f133 3 months ago 133MB
centos latest 5d0da3dc9764 3 months ago 231MB
alpine 3.12 48b8ec4ed9eb 4 months ago 5.58MB
参数
-a, --all 显示所有，包括中间层镜像
-f, --filter 过滤
-q, --quiet 仅显示 id
查看镜像信息
docker inspect [OPTIONS] NAME|ID [NAME|ID...]
例如
root@ubuntu:~# docker inspect hello-world
[
{
"Id": "sha256:feb5d9fea6a5e9606aa995e879d862b825965ba48de054caab5ef356dc6b3412",
"RepoTags": [
"hello-world:latest"
],
"RepoDigests": [
"hello-world@sha256:975f4b14f326b05db86e16de00144f9c12257553bba9484fed41f9b6f2257800"
],
"Parent": "",
"Comment": "",
"Created": "2021-09-23T23:47:57.442225064Z",
"Container": "8746661ca3c2f215da94e6d3f7dfdcafaff5ec0b21c9aff6af3dc379a82fbc72",
"ContainerConfig": {
"Hostname": "8746661ca3c2",
"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\"]"
],
"Image": "sha256:b9935d4e8431fb1a7f0989304ec86b3329a99a25f5efdc7f09f3f8c41434ca6d",
"Volumes": null,
"WorkingDir": "",
"Entrypoint": null,
"OnBuild": null,
"Labels": {}
},
"DockerVersion": "20.10.7",
"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"
],
"Image": "sha256:b9935d4e8431fb1a7f0989304ec86b3329a99a25f5efdc7f09f3f8c41434ca6d",
"Volumes": null,
"WorkingDir": "",
"Entrypoint": null,
"OnBuild": null,
"Labels": null
},
"Architecture": "amd64",
"Os": "linux",
"Size": 13256,
"VirtualSize": 13256,
"GraphDriver": {
"Data": {
"MergedDir": "/var/lib/docker/overlay2/645af721584c8ec36599fc222077d3d4e3a8de11c213bf9c48fad447603e2107/merged",
"UpperDir": "/var/lib/docker/overlay2/645af721584c8ec36599fc222077d3d4e3a8de11c213bf9c48fad447603e2107/diff",
"WorkDir": "/var/lib/docker/overlay2/645af721584c8ec36599fc222077d3d4e3a8de11c213bf9c48fad447603e2107/work"
},
"Name": "overlay2"
},
"RootFS": {
"Type": "layers",
"Layers": [
"sha256:e07ee1baac5fae6a26f30cabfe54a36d3402f96afda318fe0a96cec4ca393359"
]
},
"Metadata": {
"LastTagTime": "0001-01-01T00:00:00Z"
}
}
]
删除镜像
docker image rm [OPTIONS] IMAGE [IMAGE...]
参数：
-f, --force 强制删除
一个一个手动删除比较麻烦，可以使用 docker rmi -f $(docker images -qa) 一次性删除所有镜像
提交容器为镜像
docker commit [OPTIONS] CONTAINER [REPOSITORY[:TAG]]
首先运行容器，进入容器，并安装 vim
docker run -it centos
yum install vim -y
退出容器，可以用看到这个容器，对其 commit ，得到一个新的 image
root@VM-4-17-ubuntu:~# docker container ls -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
85f84bef3ca7 centos "/bin/bash" About a minute ago Exited (0) 8 seconds ago elegant_colden
root@VM-4-17-ubuntu:~# docker commit elegant_colden wjftu/centos-vim
sha256:5bd3de919e30d6850a531e866de5985f8ff0e82157b08b9e69bc59f0a7ef6316
root@VM-4-17-ubuntu:~# docker image ls
REPOSITORY TAG IMAGE ID CREATED SIZE
wjftu/centos-vim latest 5bd3de919e30 36 seconds ago 298MB
centos latest 5d0da3dc9764 3 months ago 231MB
root@VM-4-17-ubuntu:~# docker history 5bd3de919e30
IMAGE CREATED CREATED BY SIZE COMMENT
5bd3de919e30 4 minutes ago /bin/bash 66.3MB
5d0da3dc9764 3 months ago /bin/sh -c #(nop) CMD ["/bin/bash"] 0B
<missing> 3 months ago /bin/sh -c #(nop) LABEL org.label-schema.sc… 0B
<missing> 3 months ago /bin/sh -c #(nop) ADD file:805cb5e15fb6e0bb0… 231MB
root@VM-4-17-ubuntu:~# docker history 5d0da3dc9764
IMAGE CREATED CREATED BY SIZE COMMENT
5d0da3dc9764 3 months ago /bin/sh -c #(nop) CMD ["/bin/bash"] 0B
<missing> 3 months ago /bin/sh -c #(nop) LABEL org.label-schema.sc… 0B
<missing> 3 months ago /bin/sh -c #(nop) ADD file:805cb5e15fb6e0bb0… 231MB
这样制作 image 其实不太好，因为别人不知道是如何制作的，可能有不安全的因素。好的方法是使用 dockerfile ，别人可以根据 dockerfile 构建和你一样的 image