Docker打造最小容器MiniBash

介绍

突发奇想，做了一个无比小的容器，仅能维持shell的正常使用，无其他功能。但是吧，它确实是小，比官方宣称的busybox都要小。

制作方法

这个最小化容器制作方法是

• 找到目标程序
• 定位动态链接库
• 提取所有动态连接库
• 封装为docker
• docker作为镜像导入

运行

docker run -it jockerdragon/mini_bash:5.0 bash

构建

克隆单个分支

git clone --branch mini_bash --single-branch https://github.com/Paper-Dragon/docker-sh.git
cd docker-sh/

打包为docker可识别的rootfs

tar -cvf ../bash.tar *
cd ..
ls -lh

压缩包近3.5M

-rw-r--r-- 1 root root 3.5M  4月 18 17:25 bash.tar

导入

docker import bash.tar jockerdragon/mini_bash:5.0
sha256:7cc56da0013130d77639ffb0c137ac755d66dc39474d7321ae9642e7ebb1d0fb

运行和测试

# docker run -it jockerdragon/mini_bash:5.0 bash
[I have no name!@71d003f24aed /]#
!          ]]         break      command    coproc     done       esac       false      function   if         local      pushd      return     source     times      ulimit     wait
./         alias      builtin    compgen    declare    echo       eval       fc         getopts    in         logout     pwd        select     suspend    trap       umask      while
:          bash       caller     complete   dirs       elif       exec       fg         hash       jobs       mapfile    read       set        test       true       unalias    {
[          bg         case       compopt    disown     else       exit       fi         help       kill       popd       readarray  shift      then       type       unset      }
[[         bind       cd         continue   do         enable     export     for        history    let        printf     readonly   shopt      time       typeset    until
[I have no name!@71d003f24aed /]# pwd
/
[I have no name!@71d003f24aed /]# times
0m0.016s 0m0.016s
0m0.002s 0m0.001s
[I have no name!@71d003f24aed /]#

制作过程

/lib/terminfo/x/xterm:/lib/terminfo/x/xterm
[root@k8s-master:~/bash-rootfs]# ldd */*/*
lib/terminfo/x:
ldd: lib/terminfo/x: not regular file
lib/x86_64-linux-gnu/libc-2.31.so:
        /lib64/ld-linux-x86-64.so.2 (0x00007f095b3dd000)
        linux-vdso.so.1 (0x00007ffd18dad000)
lib/x86_64-linux-gnu/libc.so.6:
        /lib64/ld-linux-x86-64.so.2 (0x00007f5b66c6e000)
        linux-vdso.so.1 (0x00007ffe385fc000)
lib/x86_64-linux-gnu/libdl-2.31.so:
        linux-vdso.so.1 (0x00007ffeaf278000)
        libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007fafd2433000)
        /lib64/ld-linux-x86-64.so.2 (0x00007fafd2634000)
lib/x86_64-linux-gnu/libdl.so.2:
        linux-vdso.so.1 (0x00007fff1b3f6000)
        libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f6332566000)
        /lib64/ld-linux-x86-64.so.2 (0x00007f6332767000)
lib/x86_64-linux-gnu/libtinfo.so.6:
        linux-vdso.so.1 (0x00007ffd91d81000)
        libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007fa907fe9000)
        /lib64/ld-linux-x86-64.so.2 (0x00007fa908214000)
lib/x86_64-linux-gnu/libtinfo.so.6.2:
        linux-vdso.so.1 (0x00007ffe46d77000)
        libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f461ee4c000)
        /lib64/ld-linux-x86-64.so.2 (0x00007f461f077000)
usr/bin/bash:
        linux-vdso.so.1 (0x00007ffd49df6000)
        libtinfo.so.6 => /lib/x86_64-linux-gnu/libtinfo.so.6 (0x00007fd3a5d24000)
        libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007fd3a5d1e000)
        libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007fd3a5b2c000)
        /lib64/ld-linux-x86-64.so.2 (0x00007fd3a5e89000)
[root@k8s-master:~/bash-rootfs]# docker run -it --rm  jockerdragon/bash:5.0 bash
[I have no name!@d3af07f8866b /]#
[I have no name!@d3af07f8866b /]#
[root@k8s-master:~/bash-rootfs]# tar -cvf ../bash.tar *
bin/
bin/bash
etc/
etc/bash.bashrc
lib/
lib/x86_64-linux-gnu/
lib/x86_64-linux-gnu/libc-2.31.so
lib/x86_64-linux-gnu/libtinfo.so.6
lib/x86_64-linux-gnu/libdl-2.31.so
lib/x86_64-linux-gnu/libtinfo.so.6.2
lib/x86_64-linux-gnu/libdl.so.2
lib/x86_64-linux-gnu/libc.so.6
lib/terminfo/
lib/terminfo/x/
lib/terminfo/x/xterm
lib64/
lib64/ld-linux-x86-64.so.2
usr/
usr/bin/
usr/bin/bash
[root@k8s-master:~/bash-rootfs]# docker import ../bash.tar
sha256:dfdc13f29846288fc47e830dd687e28978efc1fbf7888165a7fbf72560dcacbc
[root@k8s-master:~/bash-rootfs]#