Docker(2):镜像管理

2021/8/27 6:07:36

本文主要是介绍Docker(2):镜像管理,对大家解决编程问题具有一定的参考价值,需要的程序猿们随着小编来一起学习吧!

Docker 三个非常重要的理念:

 

 三要素之间的关系:(本地和远端是逻辑上的概念 )

镜像的结构:

${registry_name}/${repository_name}/${image_name}:${tag_name}

# 如:
docker.io/library/alpine:3.10.1

 

登录 docker hub

在虚拟机上登录自己的 docker hub 账户:

~]$ docker login docker.io
Login with your Docker ID to push and pull images from Docker Hub. If you don't have a Docker ID, head over to https://hub.docker.com to create one.
Username: neomaxxxxxxx
Password: 
WARNING! Your password will be stored unencrypted in /home/ec2-user/.docker/config.json.
Configure a credential helper to remove this warning. See
https://docs.docker.com/engine/reference/commandline/login/#credentials-store

Login Succeeded


# 账户和密码保存在了 /home/ec2-user/.docker/config.json 文件中。而且是未加密的,只是进行了 base64 的 encode 。所以通过 base64 decode 可解码, 命令如下:
# echo "auth中base64加密的内容"| base64 -d

 

搜索镜像

如要搜索 alpine, 命令如下:(alpine 是 linux 的一种非常小的发行版)

~]$ docker search alpine

下载镜像:

~]$ docker pull alpine
Using default tag: latest
latest: Pulling from library/alpine
29291e31a76a: Pull complete 
Digest: sha256:eb3e4e175ba6d212ba1d6e04fc0782916c08e1c9d7b45892e9796141b1d379ae
Status: Downloaded newer image for alpine:latest
docker.io/library/alpine:latest

 

下载指定tag的镜像:

 ~]$ docker pull alpine:3.10.3
3.10.3: Pulling from library/alpine
89d9c30c1d48: Pull complete 
Digest: sha256:c19173c5ada610a5989151111163d28a67368362762534d8a8121ce95cf2bd5a
Status: Downloaded newer image for alpine:3.10.3
docker.io/library/alpine:3.10.3

 

查看本地镜像:

~]$ docker images
REPOSITORY    TAG       IMAGE ID       CREATED         SIZE
alpine        latest    021b3423115f   2 weeks ago     5.6MB
hello-world   latest    d1165f221234   5 months ago    13.3kB
alpine        3.10.3    965ea09ff2eb   22 months ago   5.55MB

 ~]$ docker image ls
REPOSITORY    TAG       IMAGE ID       CREATED         SIZE
alpine        latest    021b3423115f   2 weeks ago     5.6MB
hello-world   latest    d1165f221234   5 months ago    13.3kB
alpine        3.10.3    965ea09ff2eb   22 months ago   5.55MB

 

给镜像打标签:

~]$ docker tag 965ea09ff2eb docker.io/neomaple/alpine:v3.10.3

// docker tage image-id registry_name/repository_name/image_name:tag_name    // repository_name 就是你在 docker hub 的注册名

~]$ docker images
REPOSITORY        TAG       IMAGE ID       CREATED         SIZE
alpine            latest    021b3423115f   2 weeks ago     5.6MB
hello-world       latest    d1165f221234   5 months ago    13.3kB
alpine            3.10.3    965ea09ff2eb   22 months ago   5.55MB
neomaple/alpine   v3.10.3   965ea09ff2eb   22 months ago   5.55MB

 

推送镜像(在 login 的状态下)

 ~]$ docker push docker.io/neomaple/alpine:v3.10.3
The push refers to repository [docker.io/neomaple/alpine]
77cae8ab23bf: Mounted from library/alpine 
v3.10.3: digest: sha256:e4355b66995c96b4b468159fc5c7e3540fcef961189ca13fee877798649f531a size: 528 

也可以给本地镜像打一个新的标签 tag,命令和给镜像打标签的命令是一样的

 

 删除镜像

// 原先的镜像信息
~]$ docker images
REPOSITORY        TAG       IMAGE ID       CREATED         SIZE
alpine            latest    021b3423115f   2 weeks ago     5.6MB
hello-world       latest    d1165f221234   5 months ago    13.3kB
alpine            3.10.3    965ea09ff2eb   22 months ago   5.55MB
neomaple/alpine   v3.10.3   965ea09ff2eb   22 months ago   5.55MB

 ~]$ docker rmi docker.io/neomaple/alpine:v3.10.3
Untagged: neomaple/alpine:v3.10.3
Untagged: neomaple/alpine@sha256:e4355b66995c96b4b468159fc5c7e3540fcef961189ca13fee877798649f531a

// docker rmi 镜像tag 只是把 tag 删掉了, 其镜像并没有删除,且 docker hub 上的该镜像也没有删除
~]$ docker images
REPOSITORY    TAG       IMAGE ID       CREATED         SIZE
alpine        latest    021b3423115f   2 weeks ago     5.6MB
hello-world   latest    d1165f221234   5 months ago    13.3kB
alpine        3.10.3    965ea09ff2eb   22 months ago   5.55MB

// 想要真正删除镜像,需要用如下命令: docker rmi 镜像ID。如果该镜像在多个 repository 中被引用(或者多个标签同时指向该镜像),则删除时需要加上 -f 参数

~]$ docker rmi 965ea09ff2eb
Untagged: alpine:3.10.3
Untagged: alpine@sha256:c19173c5ada610a5989151111163d28a67368362762534d8a8121ce95cf2bd5a
Deleted: sha256:965ea09ff2ebd2b9eeec88cd822ce156f6674c7e99be082c7efac3c62f3ff652
Deleted: sha256:77cae8ab23bf486355d1b3191259705374f4a11d483b24964d2f729dd8c076a0
~]$ docker images
REPOSITORY    TAG       IMAGE ID       CREATED        SIZE
alpine        latest    021b3423115f   2 weeks ago    5.6MB
hello-world   latest    d1165f221234   5 months ago   13.3kB

 

Docker 结构示意图:

 

Docker 镜像特性:

1、 Docker 镜像位于 bootfs 之上

2、每一层镜像的下面一层称为其父镜像(父子关系)

3、第一层镜像称为 Base Image

4、容器在最顶层

5、其下所有层都为 readonly

6、Docker 将readonly 的FS层称作 "image"

 



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