docker Advent Calendar 2021 10日目の記事の紹介です。
https://qiita.com/advent-calendar/2021/docker

ご投稿ありがとうございます。

@blueskyarea Docker ホスト-コンテナ間でのユーザー/グループの分離をしたい
https://qiita.com/blueskyarea/items/7453c5782bbc16b00415

Linux上でdocker上のLinuxを動かす場合の、利用者(user)管理によるファイル管理を試されています。

現在、macOSで作業をしており、追試はできていません。ごめんなさい。

自分が興味を持ったとこだけ、おまけとして記録させてください。

記事の一番肝心な技術については、何かの機会に試させてください。

macOSのuser、Winoowsのuserとの関係の調査はいつかしてみようと思いました。

記事に関連して

dockerを使っている時に、よくやる操作誤りは、どちら側で操作しているかを忘れてしまうことです。

この記事のように、コマンドプロンプトが違うから、そんなに間違えないよという方もおみえでしょう。

私はしょっ中やらかします。

今は、macOSで操作しているから apt ってやっても動かないのでいいのですが、
ubuntu にbrewを入れてしまったら、やらかすかもしれません。

記事には、どちら側の操作かを示していただいているので安心です。

user

補足１に書かれていることの関連事項です。

Linuxの利用者(user)管理ではいろいろ痛い目にあっています。
コマンドによる利用者の追加と、設定ファイルの同期をうまく取らないと、zombie（活動死体）かghost(幽霊)になるかもしれない。

ある配布(distribution)のある版(version)では、複数のコマンドが存在しており、振る舞いが少し違うことがあったりした。

その配布のその版で、一番お勧めな方法以外は取らないようにしている。

現在のdocker上のubuntuでコマンドを見た。

bash

# useradd
Usage: useradd [options] LOGIN
       useradd -D
       useradd -D [options]

Options:
      --badnames                do not check for bad names
  -b, --base-dir BASE_DIR       base directory for the home directory of the
                                new account
      --btrfs-subvolume-home    use BTRFS subvolume for home directory
  -c, --comment COMMENT         GECOS field of the new account
  -d, --home-dir HOME_DIR       home directory of the new account
  -D, --defaults                print or change default useradd configuration
  -e, --expiredate EXPIRE_DATE  expiration date of the new account
  -f, --inactive INACTIVE       password inactivity period of the new account
  -g, --gid GROUP               name or ID of the primary group of the new
                                account
  -G, --groups GROUPS           list of supplementary groups of the new
                                account
  -h, --help                    display this help message and exit
  -k, --skel SKEL_DIR           use this alternative skeleton directory
  -K, --key KEY=VALUE           override /etc/login.defs defaults
  -l, --no-log-init             do not add the user to the lastlog and
                                faillog databases
  -m, --create-home             create the user's home directory
  -M, --no-create-home          do not create the user's home directory
  -N, --no-user-group           do not create a group with the same name as
                                the user
  -o, --non-unique              allow to create users with duplicate
                                (non-unique) UID
  -p, --password PASSWORD       encrypted password of the new account
  -r, --system                  create a system account
  -R, --root CHROOT_DIR         directory to chroot into
  -P, --prefix PREFIX_DIR       prefix directory where are located the /etc/* files
  -s, --shell SHELL             login shell of the new account
  -u, --uid UID                 user ID of the new account
  -U, --user-group              create a group with the same name as the user
  -Z, --selinux-user SEUSER     use a specific SEUSER for the SELinux user mapping
      --extrausers              Use the extra users database
# adduser -h
adduser [--home DIR] [--shell SHELL] [--no-create-home] [--uid ID]
[--firstuid ID] [--lastuid ID] [--gecos GECOS] [--ingroup GROUP | --gid ID]
[--disabled-password] [--disabled-login] [--add_extra_groups]
[--encrypt-home] USER
   Add a normal user

adduser --system [--home DIR] [--shell SHELL] [--no-create-home] [--uid ID]
[--gecos GECOS] [--group | --ingroup GROUP | --gid ID] [--disabled-password]
[--disabled-login] [--add_extra_groups] USER
   Add a system user

adduser --group [--gid ID] GROUP
addgroup [--gid ID] GROUP
   Add a user group

addgroup --system [--gid ID] GROUP
   Add a system group

adduser USER GROUP
   Add an existing user to an existing group

general options:
  --quiet | -q      don't give process information to stdout
  --force-badname   allow usernames which do not match the
                    NAME_REGEX[_SYSTEM] configuration variable
  --extrausers      uses extra users as the database
  --help | -h       usage message
  --version | -v    version number and copyright
  --conf | -c FILE  use FILE as configuration file

did

docker 内でdockerを起動する方法を探しました。

docker コマンドは導入できますが、dockerコマンドが見当たりません。

結果として、やってみたいことのやり方は見つかりませんでした。

docker上でPOSIXのTestSuiteの実行をしていないことに気がつきました。

別記事で立てようと思いました。

bash

# docker run -it ubuntu /bin/bash

bash

# apt update; apt -y upgrade
# apt -y install docker
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following additional packages will be installed:
  libbsd0 libglib2.0-0 libglib2.0-data libicu66 libx11-6 libx11-data libxau6 libxcb1 libxdmcp6 libxml2 shared-mime-info tzdata wmdocker
  xdg-user-dirs
The following NEW packages will be installed:
  docker libbsd0 libglib2.0-0 libglib2.0-data libicu66 libx11-6 libx11-data libxau6 libxcb1 libxdmcp6 libxml2 shared-mime-info tzdata
  wmdocker xdg-user-dirs
0 upgraded, 15 newly installed, 0 to remove and 0 not upgraded.
Need to get 12.0 MB of archives.
After this operation, 50.5 MB of additional disk space will be used.
Get:1 http://archive.ubuntu.com/ubuntu focal/main amd64 libbsd0 amd64 0.10.0-1 [45.4 kB]
Get:2 http://archive.ubuntu.com/ubuntu focal-updates/main amd64 libglib2.0-0 amd64 2.64.6-1~ubuntu20.04.4 [1287 kB]
Get:3 http://archive.ubuntu.com/ubuntu focal-updates/main amd64 libglib2.0-data all 2.64.6-1~ubuntu20.04.4 [6052 B]
Get:4 http://archive.ubuntu.com/ubuntu focal-updates/main amd64 tzdata all 2021e-0ubuntu0.20.04 [295 kB]
Get:5 http://archive.ubuntu.com/ubuntu focal-updates/main amd64 libicu66 amd64 66.1-2ubuntu2.1 [8515 kB]
Get:6 http://archive.ubuntu.com/ubuntu focal-updates/main amd64 libxml2 amd64 2.9.10+dfsg-5ubuntu0.20.04.1 [640 kB]
Get:7 http://archive.ubuntu.com/ubuntu focal/main amd64 shared-mime-info amd64 1.15-1 [430 kB]
Get:8 http://archive.ubuntu.com/ubuntu focal/main amd64 xdg-user-dirs amd64 0.17-2ubuntu1 [48.3 kB]
Get:9 http://archive.ubuntu.com/ubuntu focal/main amd64 libxau6 amd64 1:1.0.9-0ubuntu1 [7488 B]
Get:10 http://archive.ubuntu.com/ubuntu focal/main amd64 libxdmcp6 amd64 1:1.1.3-0ubuntu1 [10.6 kB]
Get:11 http://archive.ubuntu.com/ubuntu focal/main amd64 libxcb1 amd64 1.14-2 [44.7 kB]
Get:12 http://archive.ubuntu.com/ubuntu focal-updates/main amd64 libx11-data all 2:1.6.9-2ubuntu1.2 [113 kB]
Get:13 http://archive.ubuntu.com/ubuntu focal-updates/main amd64 libx11-6 amd64 2:1.6.9-2ubuntu1.2 [575 kB]
Get:14 http://archive.ubuntu.com/ubuntu focal/universe amd64 wmdocker amd64 1.5-2 [13.0 kB]
Get:15 http://archive.ubuntu.com/ubuntu focal/universe amd64 docker all 1.5-2 [1316 B]
Fetched 12.0 MB in 5s (2219 kB/s)
debconf: delaying package configuration, since apt-utils is not installed
Selecting previously unselected package libbsd0:amd64.
(Reading database ... 4127 files and directories currently installed.)
Preparing to unpack .../00-libbsd0_0.10.0-1_amd64.deb ...
Unpacking libbsd0:amd64 (0.10.0-1) ...
Selecting previously unselected package libglib2.0-0:amd64.
Preparing to unpack .../01-libglib2.0-0_2.64.6-1~ubuntu20.04.4_amd64.deb ...
Unpacking libglib2.0-0:amd64 (2.64.6-1~ubuntu20.04.4) ...
Selecting previously unselected package libglib2.0-data.
Preparing to unpack .../02-libglib2.0-data_2.64.6-1~ubuntu20.04.4_all.deb ...
Unpacking libglib2.0-data (2.64.6-1~ubuntu20.04.4) ...
Selecting previously unselected package tzdata.
Preparing to unpack .../03-tzdata_2021e-0ubuntu0.20.04_all.deb ...
Unpacking tzdata (2021e-0ubuntu0.20.04) ...
Selecting previously unselected package libicu66:amd64.
Preparing to unpack .../04-libicu66_66.1-2ubuntu2.1_amd64.deb ...
Unpacking libicu66:amd64 (66.1-2ubuntu2.1) ...
Selecting previously unselected package libxml2:amd64.
Preparing to unpack .../05-libxml2_2.9.10+dfsg-5ubuntu0.20.04.1_amd64.deb ...
Unpacking libxml2:amd64 (2.9.10+dfsg-5ubuntu0.20.04.1) ...
Selecting previously unselected package shared-mime-info.
Preparing to unpack .../06-shared-mime-info_1.15-1_amd64.deb ...
Unpacking shared-mime-info (1.15-1) ...
Selecting previously unselected package xdg-user-dirs.
Preparing to unpack .../07-xdg-user-dirs_0.17-2ubuntu1_amd64.deb ...
Unpacking xdg-user-dirs (0.17-2ubuntu1) ...
Selecting previously unselected package libxau6:amd64.
Preparing to unpack .../08-libxau6_1%3a1.0.9-0ubuntu1_amd64.deb ...
Unpacking libxau6:amd64 (1:1.0.9-0ubuntu1) ...
Selecting previously unselected package libxdmcp6:amd64.
Preparing to unpack .../09-libxdmcp6_1%3a1.1.3-0ubuntu1_amd64.deb ...
Unpacking libxdmcp6:amd64 (1:1.1.3-0ubuntu1) ...
Selecting previously unselected package libxcb1:amd64.
Preparing to unpack .../10-libxcb1_1.14-2_amd64.deb ...
Unpacking libxcb1:amd64 (1.14-2) ...
Selecting previously unselected package libx11-data.
Preparing to unpack .../11-libx11-data_2%3a1.6.9-2ubuntu1.2_all.deb ...
Unpacking libx11-data (2:1.6.9-2ubuntu1.2) ...
Selecting previously unselected package libx11-6:amd64.
Preparing to unpack .../12-libx11-6_2%3a1.6.9-2ubuntu1.2_amd64.deb ...
Unpacking libx11-6:amd64 (2:1.6.9-2ubuntu1.2) ...
Selecting previously unselected package wmdocker.
Preparing to unpack .../13-wmdocker_1.5-2_amd64.deb ...
Unpacking wmdocker (1.5-2) ...
Selecting previously unselected package docker.
Preparing to unpack .../14-docker_1.5-2_all.deb ...
Unpacking docker (1.5-2) ...
Setting up libxau6:amd64 (1:1.0.9-0ubuntu1) ...
Setting up xdg-user-dirs (0.17-2ubuntu1) ...
Setting up libglib2.0-0:amd64 (2.64.6-1~ubuntu20.04.4) ...
No schema files found: doing nothing.
Setting up tzdata (2021e-0ubuntu0.20.04) ...
debconf: unable to initialize frontend: Dialog
debconf: (No usable dialog-like program is installed, so the dialog based frontend cannot be used. at /usr/share/perl5/Debconf/FrontEnd/Dialog.pm line 76.)
debconf: falling back to frontend: Readline
debconf: unable to initialize frontend: Readline
debconf: (Can't locate Term/ReadLine.pm in @INC (you may need to install the Term::ReadLine module) (@INC contains: /etc/perl /usr/local/lib/x86_64-linux-gnu/perl/5.30.0 /usr/local/share/perl/5.30.0 /usr/lib/x86_64-linux-gnu/perl5/5.30 /usr/share/perl5 /usr/lib/x86_64-linux-gnu/perl/5.30 /usr/share/perl/5.30 /usr/local/lib/site_perl /usr/lib/x86_64-linux-gnu/perl-base) at /usr/share/perl5/Debconf/FrontEnd/Readline.pm line 7.)
debconf: falling back to frontend: Teletype
Configuring tzdata
------------------

Please select the geographic area in which you live. Subsequent configuration questions will narrow this down by presenting a list of cities,
representing the time zones in which they are located.

  1. Africa   3. Antarctica  5. Arctic  7. Atlantic  9. Indian    11. SystemV  13. Etc
  2. America  4. Australia   6. Asia    8. Europe    10. Pacific  12. US
Geographic area: 6

Please select the city or region corresponding to your time zone.

  1. Aden      13. Barnaul     25. Dushanbe     37. Jerusalem     49. Macau         61. Pyongyang      73. Taipei         85. Vientiane
  2. Almaty    14. Beirut      26. Famagusta    38. Kabul         50. Magadan       62. Qatar          74. Tashkent       86. Vladivostok
  3. Amman     15. Bishkek     27. Gaza         39. Kamchatka     51. Makassar      63. Qostanay       75. Tbilisi        87. Yakutsk
  4. Anadyr    16. Brunei      28. Harbin       40. Karachi       52. Manila        64. Qyzylorda      76. Tehran         88. Yangon
  5. Aqtau     17. Chita       29. Hebron       41. Kashgar       53. Muscat        65. Rangoon        77. Tel_Aviv       89. Yekaterinburg
  6. Aqtobe    18. Choibalsan  30. Ho_Chi_Minh  42. Kathmandu     54. Nicosia       66. Riyadh         78. Thimphu        90. Yerevan
  7. Ashgabat  19. Chongqing   31. Hong_Kong    43. Khandyga      55. Novokuznetsk  67. Sakhalin       79. Tokyo
  8. Atyrau    20. Colombo     32. Hovd         44. Kolkata       56. Novosibirsk   68. Samarkand      80. Tomsk
  9. Baghdad   21. Damascus    33. Irkutsk      45. Krasnoyarsk   57. Omsk          69. Seoul          81. Ujung_Pandang
  10. Bahrain  22. Dhaka       34. Istanbul     46. Kuala_Lumpur  58. Oral          70. Shanghai       82. Ulaanbaatar
  11. Baku     23. Dili        35. Jakarta      47. Kuching       59. Phnom_Penh    71. Singapore      83. Urumqi
  12. Bangkok  24. Dubai       36. Jayapura     48. Kuwait        60. Pontianak     72. Srednekolymsk  84. Ust-Nera
Time zone: 79


Current default time zone: 'Asia/Tokyo'
Local time is now:      Sat Jan  8 11:27:04 JST 2022.
Universal Time is now:  Sat Jan  8 02:27:04 UTC 2022.
Run 'dpkg-reconfigure tzdata' if you wish to change it.

Setting up libglib2.0-data (2.64.6-1~ubuntu20.04.4) ...
Setting up libx11-data (2:1.6.9-2ubuntu1.2) ...
Setting up libbsd0:amd64 (0.10.0-1) ...
Setting up libxdmcp6:amd64 (1:1.1.3-0ubuntu1) ...
Setting up libxcb1:amd64 (1.14-2) ...
Setting up libicu66:amd64 (66.1-2ubuntu2.1) ...
Setting up libx11-6:amd64 (2:1.6.9-2ubuntu1.2) ...
Setting up libxml2:amd64 (2.9.10+dfsg-5ubuntu0.20.04.1) ...
Setting up wmdocker (1.5-2) ...
Setting up shared-mime-info (1.15-1) ...
Setting up docker (1.5-2) ...
Processing triggers for libc-bin (2.31-0ubuntu9.2) ...
root@1957b5c49435:/# docker run -it ubuntu /bin/bash
bash: docker: command not found
root@1957b5c49435:/# /bin/docker 
bash: /bin/docker: No such file or directory
root@1957b5c49435:/# /sbin/docker
bash: /sbin/docker: No such file or directory
root@1957b5c49435:/# find / -name docker -print
/usr/share/doc/docker

did 参考資料

Docker in Docker のベタープラクティス

Dockerコンテナ内からDockerを使うことについて

docker in docker(dind)を使ってみる

参考資料

Linuxbrew のススメ
https://qiita.com/thermes/items/926b478ff6e3758ecfea

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