Managing /etc with etckeeper

3 minute read

Background on /etc and version control

I manage a number of Linux machines ranginge from servers to laptops. I have little interest in babysitting /etc and all the excitement that happens there. I try to avoid modifing files in /etc so that future upgrades are slightly more seemless. However, somethings absolutely need to be modified.

A long time ago I started using svn for watching all the files under /etc. Some issues with the filesystem caused files to get corrupted. The corrupted files were quickly restored from the local svn repository. Another machine had a site it hosted compromised. Having things under version control enabled me to quickly validate the contents of /etc. Lessons learned that payback dividends.

Fast forward several years and Linus Torvalds created git, and invevitably I fell in love with git. With git we can do all of the same things, just easier. Git is a distributed version control system so that makes setting up the repository and pushing it to remove machines for back-up are also much easier.

I have since learned that Joey Hess of git annex fame created etckeeper, which makes all this even easier.

Setup etckeeper on Ubuntu 12.04:

  1. Install etckeeper on a Debian based distribution:

     $ sudo apt-get install etckeeper
    
  2. Edit /etc/etckeeper/etckeeper.conf, commented out the VCS=”bzr” line and uncomment the VCS=”git” line. One-liner:

     $ sed -e 's:^\(VCS\s*=.*bzr\):#\1:' -e 's:^#\(VCS\s*=.*git\):\1:' -i /etc/etckeeper/etckeeper.conf
    
  3. Initialize the repository:

     $ cd /etc
     $ sudo etckeeper init
    
  4. Ensure the the /etc/.git directory has safe permissions, should only be readable by root. Should this change, anyone who can read the git repoository can read all the the /etc files stored in the repository as objects.:

     $ ls -ld /etc/.git
     drwx------ 1 root root 108 Aug  7 22:27 /etc/.git
    
  5. Create the initial commit:

     $ sudo etckeeper commit "Initial commit"
    

Tour of etckeeper

  • Etckeeper sets up gitignore for you:

      $ cat /etc/.gitignore
    
  • View the git log:

      $ cd /etc
      $ sudo git log
      commit 1726dc3a2330216548b7adc99cce402cc39a5a9c
      Author: nitro <[email protected]>
      Date:   Tue Aug 21 17:44:47 2012 -0500
    
          committing changes in /etc after apt run
    
          Package changes:
          +lftp 4.3.3-1
    
       lftp.conf |   94 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
       1 file changed, 94 insertions(+)
    
      commit af34fb96471751709ef3b2abb18cedb058ff31fa
      Author: nitro <[email protected]>
      Date:   Tue Aug 14 21:00:58 2012 -0500
    
          committing changes in /etc after apt run
    
          Package changes:
          -base-files 6.5ubuntu6
          +base-files 6.5ubuntu6.2
          -fonts-opensymbol 2:102.2+LibO3.5.4-0ubuntu1
          +fonts-opensymbol 2:102.2+LibO3.5.4-0ubuntu1.1
          -gir1.2-launchpad-integration-3.0 0.1.56
          +gir1.2-launchpad-integration-3.0 0.1.56.1
          -google-chrome-stable 21.0.1180.75-r150248
          +google-chrome-stable 21.0.1180.77-r150576
          -launchpad-integration 0.1.56
          +launchpad-integration 0.1.56.1
          -libbonobo2-0 2.32.1-0ubuntu1
          -libbonobo2-common 2.32.1-0ubuntu1
          -libbonoboui2-0 2.24.5-0ubuntu1
          -libbonoboui2-common 2.24.5-0ubuntu1
          +libbonobo2-0 2.32.1-0ubuntu1.1
          +libbonobo2-common 2.32.1-0ubuntu1.1
          +libbonoboui2-0 2.24.5-0ubuntu1.1
          +libbonoboui2-common 2.24.5-0ubuntu1.1
          -liblaunchpad-integration-3.0-1 0.1.56
          -liblaunchpad-integration-common 0.1.56
          -liblaunchpad-integration1 0.1.56
          +liblaunchpad-integration-3.0-1 0.1.56.1
          +liblaunchpad-integration-common 0.1.56.1
          +liblaunchpad-integration1 0.1.56.1
          -libnspr4 4.8.9-1ubuntu2
          -libnspr4-0d 4.8.9-1ubuntu2
          +libnspr4 4.8.9-1ubuntu2.1
          +libnspr4-0d 4.8.9-1ubuntu2.1
          -libreoffice-base-core 1:3.5.4-0ubuntu1
          -libreoffice-calc 1:3.5.4-0ubuntu1
          -libreoffice-common 1:3.5.4-0ubuntu1
          -libreoffice-core 1:3.5.4-0ubuntu1
          -libreoffice-draw 1:3.5.4-0ubuntu1
          -libreoffice-emailmerge 1:3.5.4-0ubuntu1
          -libreoffice-gnome 1:3.5.4-0ubuntu1
          -libreoffice-gtk 1:3.5.4-0ubuntu1
          -libreoffice-help-en-us 1:3.5.4-0ubuntu1
          -libreoffice-impress 1:3.5.4-0ubuntu1
          -libreoffice-math 1:3.5.4-0ubuntu1
          -libreoffice-style-human 1:3.5.4-0ubuntu1
          -libreoffice-style-tango 1:3.5.4-0ubuntu1
          -libreoffice-writer 1:3.5.4-0ubuntu1
          +libreoffice-base-core 1:3.5.4-0ubuntu1.1
          +libreoffice-calc 1:3.5.4-0ubuntu1.1
          +libreoffice-common 1:3.5.4-0ubuntu1.1
          +libreoffice-core 1:3.5.4-0ubuntu1.1
          +libreoffice-draw 1:3.5.4-0ubuntu1.1
          +libreoffice-emailmerge 1:3.5.4-0ubuntu1.1
          +libreoffice-gnome 1:3.5.4-0ubuntu1.1
          +libreoffice-gtk 1:3.5.4-0ubuntu1.1
          +libreoffice-help-en-us 1:3.5.4-0ubuntu1.1
          +libreoffice-impress 1:3.5.4-0ubuntu1.1
          +libreoffice-math 1:3.5.4-0ubuntu1.1
          +libreoffice-style-human 1:3.5.4-0ubuntu1.1
          +libreoffice-style-tango 1:3.5.4-0ubuntu1.1
          +libreoffice-writer 1:3.5.4-0ubuntu1.1
          -light-themes 0.1.9.1-0ubuntu1
          +light-themes 0.1.9.1-0ubuntu1.1
          -mdadm 3.2.3-2ubuntu1
          +mdadm 3.2.5-1ubuntu0.2
          -python-uno 1:3.5.4-0ubuntu1
          +python-uno 1:3.5.4-0ubuntu1.1
          -sessioninstaller 0.20+bzr128-0ubuntu1
          +sessioninstaller 0.20+bzr128-0ubuntu1.1
          -uno-libs3 3.5.4-0ubuntu1
          +uno-libs3 3.5.4-0ubuntu1.1
          -update-manager 1:0.156.14.6
          -update-manager-core 1:0.156.14.6
          -update-notifier 0.119ubuntu8.4
          -update-notifier-common 0.119ubuntu8.4
          +update-manager 1:0.156.14.9
          +update-manager-core 1:0.156.14.9
          +update-notifier 0.119ubuntu8.5
          +update-notifier-common 0.119ubuntu8.5
          -ure 3.5.4-0ubuntu1
          +ure 3.5.4-0ubuntu1.1
          -xserver-common 2:1.11.4-0ubuntu10.6
          +xserver-common 2:1.11.4-0ubuntu10.7
          -xserver-xorg-core 2:1.11.4-0ubuntu10.6
          +xserver-xorg-core 2:1.11.4-0ubuntu10.7
    
       bonobo-activation/bonobo-activation-config.xml |    1 +
       issue                                          |    2 +-
       issue.net                                      |    2 +-
       lsb-release                                    |    2 +-
       4 files changed, 4 insertions(+), 3 deletions(-)
    

Shortcomings

When I managed my git repos myself, in the days before etckeeper, I would make a habit of specifying the author with commits. Consequently, on shared servers administered by groups of people, I made a big deal out of everyone specifying the author when they modified files under /etc. The result was a real traceable history, and no more initials and comments from co-workers and friends about who changed what and why as the git log provided all this.

It does appear to grab the $SUDO_USER environmental variable though, so that helps a little. However, on lightweight virtual machines without real users and multiple admins, it will always say the author is [email protected].

I’m unaware of any ways to do this under etckeeper now. Perhaps someday I’ll get around to writing a patch to do it and submit it upstream.

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