docker-anpine镜像介绍

痛定思痛。 2023-01-18 04:15 22阅读 0赞

Alpine 操作系统是一个面向安全的轻型 Linux 发行版。它不同于通常 Linux 发行版，Alpine 采用了 musl libc 和 busybox 以减小系统的体积和运行时资源消耗，但功能上比 busybox 又完善的多，因此得到开源社区越来越多的青睐。在保持瘦身的同时，Alpine 还提供了自己的包管理工具 apk，可以通过 [https://pkgs.alpinelinux.org/packages][https_pkgs.alpinelinux.org_packages] 网站上查询包信息，也可以直接通过 apk 命令直接查询和安装各种软件。

Alpine 由非商业组织维护的，支持广泛场景的 Linux发行版，它特别为资深/重度Linux用户而优化，关注安全，性能和资源效能。Alpine 镜像可以适用于更多常用场景，并且是一个优秀的可以适用于生产的基础系统/环境。

Alpine Docker 镜像也继承了 Alpine Linux 发行版的这些优势。相比于其他 Docker 镜像，它的容量非常小，仅仅只有 5 MB 左右（对比 Ubuntu 系列镜像接近 200 MB），且拥有非常友好的包管理机制。官方镜像来自 docker-alpine 项目。

目前 Docker 官方已开始推荐使用 Alpine 替代之前的 Ubuntu 做为基础镜像环境。这样会带来多个好处。包括镜像下载速度加快，镜像安全性提高，主机之间的切换更方便，占用更少磁盘空间等。

下表是官方镜像的大小比较：

REPOSITORY          TAG           IMAGE ID          VIRTUAL SIZE
    alpine              latest        4e38e38c8ce0      4.799 MB
    debian              latest        4d6ce913b130      84.98 MB
    ubuntu              latest        b39b81afc8ca      188.3 MB
    centos              latest        8efe422e6104      210 MB

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–`Alpine`官网：[https://www.alpinelinux.org/][https_www.alpinelinux.org]  
–`Alpine`官方仓库：[https://github.com/alpinelinux][https_github.com_alpinelinux]  
–`MARKDOWN_HASH45a94c5ae2df00c49cca09d7d26c06ecMARKDOWNHASH`*官方镜像：[https://hub.docker.com/][https_hub.docker.com]*/alpine/  
–`Alpine`官方镜像仓库：[https://github.com/gliderlabs/docker-alpine][https_github.com_gliderlabs_docker-alpine]  
–`Alpine`阿里云的镜像仓库：[https://mirrors.aliyun.com/alpine/][https_mirrors.aliyun.com_alpine]

范例：alpine安装软件

#修改源替换成阿里源，将里面 dl-cdn.alpinelinux.org 的 改成 mirrors.aliyun.com
    vi etc/apk/repositories
    http://mirrors.aliyun.com/alpine/v3.8/main/
    http://mirrors.aliyun.com/alpine/v3.8/community/
    
    #更新源
    apk update
    
    #安装软件
    apk add vim
    
    #删除软件
    apk del openssh openntp vim

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范例：

/ # apk --help
    apk-tools 2.10.4, compiled for x86_64.
    
    Installing and removing packages:
      add       Add PACKAGEs to 'world' and install (or upgrade) them, while ensuring that all dependencies are met
      del       Remove PACKAGEs from 'world' and uninstall them
    
    System maintenance:
      fix       Repair package or upgrade it without modifying main dependencies
      update    Update repository indexes from all remote repositories
      upgrade   Upgrade currently installed packages to match repositories
      cache     Download missing PACKAGEs to cache and/or delete unneeded files from cache
    
    Querying information about packages:
      info      Give detailed information about PACKAGEs or repositories
      list      List packages by PATTERN and other criteria
      dot       Generate graphviz graphs
      policy    Show repository policy for packages
    
    Repository maintenance:
      index     Create repository index file from FILEs
      fetch     Download PACKAGEs from global repositories to a local directory
      verify    Verify package integrity and signature
      manifest  Show checksums of package contents
    
    Use apk <command> --help for command-specific help.
    Use apk --help --verbose for a full command listing.
    
    This apk has coffee making abilities.
    
    / # apk add  nginx
    / # apk info nginx
    nginx-1.16.1-r6 description:
    HTTP and reverse proxy server (stable version)
    
    nginx-1.16.1-r6 webpage:
    https://www.nginx.org/
    
    nginx-1.16.1-r6 installed size:
    1126400
    
    ~ # apk manifest nginx
    sha1:d21a96358a10b731f8847e6d32799efdc2a7f421  etc/logrotate.d/nginx
    sha1:50bd6d3b4f3e6b577d852f12cd6939719d2c2db5  etc/init.d/nginx
    sha1:379c1e2a2a5ffb8c91a07328d4c9be2bc58799fd  etc/nginx/scgi_params
    sha1:da38e2a0dded838afbe0eade6cb837ac30fd8046  etc/nginx/fastcgi_params
    sha1:cc2fcdb4605dcac23d59f667889ccbdfdc6e3668  etc/nginx/uwsgi_params
    sha1:cbf596ddb3433a8e0d325f3c188bec9c1bb746b3  etc/nginx/fastcgi.conf
    sha1:e39dbc36680b717ec902fadc805a302f1cf62245  etc/nginx/mime.types
    sha1:e9dddf20f1196bb67eef28107438b60c4060f4d3  etc/nginx/nginx.conf
    sha1:7b2a4da1a14166442c10cbf9e357fa9fb53542ca  etc/nginx/conf.d/default.conf
    sha1:cd7f5dc8ccdc838a2d0107511c90adfe318a81e7  etc/conf.d/nginx
    sha1:05f050f6ed86c5e6b48c2d2328e81583315431be  usr/sbin/nginx
    sha1:c3f02ca81f7f2c6bde3f878b3176f225c7781c7d  var/lib/nginx/modules
    sha1:0510312d465b86769136983657df98c1854f0b60  var/lib/nginx/run
    sha1:35db17c18ce0b9f84a3cc113c8a9e94e19f632b1  var/lib/nginx/logs
    sha1:7dd71afcfb14e105e80b0c0d7fce370a28a41f0a  var/lib/nginx/html/index.html
    sha1:95de71d58b37f9f74bede0e91bc381d6059fc2d7  var/lib/nginx/html/50x.html
    ~ # ls -l /bin
    total 824
    lrwxrwxrwx    1 root     root            12 Jan 16 21:52 arch -> /bin/busybox
    lrwxrwxrwx    1 root     root            12 Jan 16 21:52 ash -> /bin/busybox
    lrwxrwxrwx    1 root     root            12 Jan 16 21:52 base64 -> /bin/busybox
    lrwxrwxrwx    1 root     root            12 Jan 16 21:52 bbconfig -> /bin/busybox
    -rwxr-xr-x    1 root     root        841288 Jan 15 10:36 busybox
    lrwxrwxrwx    1 root     root            12 Jan 16 21:52 cat -> /bin/busybox
    lrwxrwxrwx    1 root     root            12 Jan 16 21:52 chgrp -> /bin/busybox
    lrwxrwxrwx    1 root     root            12 Jan 16 21:52 chmod -> /bin/busybox
    lrwxrwxrwx    1 root     root            12 Jan 16 21:52 chown -> /bin/busybox

下载镜像

从docker 仓库将镜像下载到本地，命令格式如下：

docker pull  仓库服务器:端口/项目名称/镜像名称:tag(版本)号

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镜像下载保存的路径：

/var/lib/docker/overlay2/镜像ID

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注意：镜像下载完成后，会自动解压缩，比官网显示的可能会大很多，如： centos8.1.1911下载时只有70MB，下载完后显示237MB

范例：从docker官网下载镜像

docker pull hello-world
    docker pull alpine
    docker pull busybox
    docker pull nginx    
    docker pull centos
    docker pull centos:centos7.7.1908
    docker pull docker.io/library/mysql:5.7.29
    docker pull mysql:5.6.47

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范例：下载镜像alpine

[root@ubuntu1804 ~]#ls /var/lib/docker/overlay2/
    l
    [root@ubuntu1804 ~]#du -sh /var/lib/docker/overlay2
    8.0K    /var/lib/docker/overlay2
    [root@ubuntu1804 ~]#ls /var/lib/docker/overlay2/l
    [root@ubuntu1804 ~]#docker pull hello-world
    Using default tag: latest
    latest: Pulling from library/hello-world
    1b930d010525: Pull complete 
    Digest: sha256:9572f7cdcee8591948c2963463447a53466950b3fc15a247fcad1917ca215a2f
    Status: Downloaded newer image for hello-world:latest
    docker.io/library/hello-world:latest
    [root@ubuntu1804 ~]#docker pull alpine:3.11.3
    3.11.3: Pulling from library/alpine
    c9b1b535fdd9: Pull complete 
    Digest: sha256:ab00606a42621fb68f2ed6ad3c88be54397f981a7b70a79db3d1172b11c4367d
    Status: Downloaded newer image for alpine:3.11.3
    docker.io/library/alpine:3.11.3
    [root@ubuntu1804 ~]#docker pull busybox
    Using default tag: latest
    latest: Pulling from library/busybox
    bdbbaa22dec6: Pull complete 
    Digest: sha256:6915be4043561d64e0ab0f8f098dc2ac48e077fe23f488ac24b665166898115a
    Status: Downloaded newer image for busybox:latest
    docker.io/library/busybox:latest
    [root@ubuntu1804 ~]#docker pull centos:centos8.1.1911
    centos8.1.1911: Pulling from library/centos
    8a29a15cefae: Pull complete 
    Digest: sha256:fe8d824220415eed5477b63addf40fb06c3b049404242b31982106ac204f6700
    Status: Downloaded newer image for centos:centos8.1.1911
    docker.io/library/centos:centos8.1.1911
    [root@ubuntu1804 ~]#du -sh /var/lib/docker/overlay2/*
    5.9M    /var/lib/docker/overlay2/1802616f4c8e0a0b52c839431b6faa8ac21f4bd831548dcbd46943d3f60061fa
    16K /var/lib/docker/overlay2/5773b92e1351da5e589d0573d9f22d1ec3be1e0e98edbfcddba4b830f12c7be2
    1.3M    /var/lib/docker/overlay2/de31641b8d2207de7f08eabb5240474a1aaccfef08b6034dcee02b9623f8d9dc
    252M    /var/lib/docker/overlay2/f41df336075611f9e358e5eaf2ebd5089920a90ba68760cdec8da03edff362f7
    20K /var/lib/docker/overlay2/l
    [root@ubuntu1804 ~]#docker images 
    REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
    alpine              3.11.3              e7d92cdc71fe        7 days ago          5.59MB
    centos              centos8.1.1911      470671670cac        7 days ago          237MB
    busybox             latest              6d5fcfe5ff17        4 weeks ago         1.22MB
    hello-world         latest              fce289e99eb9        12 months ago       1.84kB
    
    [root@ubuntu1804 ~]#ls -l  /var/lib/docker/overlay2/l
    total 16
    lrwxrwxrwx 1 root root 72 Jan 25 19:51 C5ZTDYHYDTO7BQG6HX36MU6X5K -> ../de31641b8d2207de7f08eabb5240474a1aaccfef08b6034dcee02b9623f8d9dc/diff
    lrwxrwxrwx 1 root root 72 Jan 25 19:57 DEXHVNUGFLFJCSJAKISOHQG7JY -> ../f41df336075611f9e358e5eaf2ebd5089920a90ba68760cdec8da03edff362f7/diff
    lrwxrwxrwx 1 root root 72 Jan 25 19:51 KJ5IA5AUHFUEQXFKJA7UDUIA7A -> ../1802616f4c8e0a0b52c839431b6faa8ac21f4bd831548dcbd46943d3f60061fa/diff
    lrwxrwxrwx 1 root root 72 Jan 25 19:51 ZM3U4WDNHGJJX5DXHA5M4ZWAIW -> ../5773b92e1351da5e589d0573d9f22d1ec3be1e0e98edbfcddba4b830f12c7be2/diff

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范例：

[root@ubuntu1804 ~]#docker pull docker.io/library/mysql:5.7.29
    5.7.29: Pulling from library/mysql
    804555ee0376: Pull complete 
    c53bab458734: Pull complete 
    ca9d72777f90: Pull complete 
    2d7aad6cb96e: Pull complete 
    8d6ca35c7908: Pull complete 
    6ddae009e760: Pull complete 
    327ae67bbe7b: Pull complete 
    9e05241b7707: Pull complete 
    e822978df8f0: Pull complete 
    14ca71ed53be: Pull complete 
    026afe6fd35e: Pull complete 
    Digest: sha256:2ca675966612f34b4036bbcfa68cb049c03e34b561fba0f88954b03931823d29
    Status: Downloaded newer image for mysql:5.7.29
    docker.io/library/mysql:5.7.29
    [root@ubuntu1804 ~]#docker pull mysql:5.6.47

[https_pkgs.alpinelinux.org_packages]: http://www.yunweipai.com/go?_=3667b35af3aHR0cHM6Ly9wa2dzLmFscGluZWxpbnV4Lm9yZy9wYWNrYWdlcw==
[https_www.alpinelinux.org]: http://www.yunweipai.com/go?_=95403a77afaHR0cHM6Ly93d3cuYWxwaW5lbGludXgub3JnLw==
[https_github.com_alpinelinux]: http://www.yunweipai.com/go?_=bd05d4dd36aHR0cHM6Ly9naXRodWIuY29tL2FscGluZWxpbnV4
[https_hub.docker.com]: http://www.yunweipai.com/go?_=ba6c70463baHR0cHM6Ly9odWIuZG9ja2VyLmNvbS8=
[https_github.com_gliderlabs_docker-alpine]: http://www.yunweipai.com/go?_=e773a9e231aHR0cHM6Ly9naXRodWIuY29tL2dsaWRlcmxhYnMvZG9ja2VyLWFscGluZQ==
[https_mirrors.aliyun.com_alpine]: http://www.yunweipai.com/go?_=20632e4443aHR0cHM6Ly9taXJyb3JzLmFsaXl1bi5jb20vYWxwaW5lLw==