etckeeper

Related articles

• Git
• Cron

Etckeeper is a collection of tools to keep track of /etc/ in a repository (Git, Mercurial, Bazaar or Darcs are supported). A pacman hook auto-commits changes before a system-upgrade and file permissions are tracked, which version control does not normally support, but is important for files like /etc/shadow.

Installation

Install the etckeeper package.

Configuration

The preferred version control system (default is git) and other options are to be configured in /etc/etckeeper/etckeeper.conf.

Etckeeper supports using pacman as a LOWLEVEL_PACKAGE_MANAGER and HIGHLEVEL_PACKAGE_MANAGER in etckeeper.conf.

Usage

After configuration the repository for the /etc path has to be initialized:

# etckeeper init

And perform a first commit to keep track of the changes, this is a necessary step for etckeeper to be able to work automatically:

# etckeeper commit "first commit"

As of etckeeper version 1.18.3-1, pre-install and post-install pacman hooks are executed automatically on package installation, update and removal. A manual #Wrapper script is not required anymore.

To track other changes to the /etc path, you need to either commit changes manually (see the etckeeper(8) man page for commands) or use one of the stopgap solutions below.

systemd

Service and timer units are included in the package. Simply enable etckeeper.timer.

# systemctl enable etckeeper.timer

See Systemd/Timers for more information and Systemd#Editing provided units if you wish to edit the provided units.

Cron

There is a cron script in the source distribution. You can use this script to automatically commit changes on a schedule.

For example, to make it run daily:

1. Have cron installed and enabled.
2. Put script as /etc/cron.daily/script_name.
3. Permit execution of file for root (As the root user run chmod u+x /etc/cron.daily/script_name).

See cron#Cronie, cron for more information.

Incron

Note: This section applies only to incron version 5.10.

To automatically create commits on every file modification inside /etc/, use incron. It utilizes native filesystem signalling through inotify(7).

After installing incron and initializing etckeeper, add root to the users allowed to run incron scripts:

# echo root | tee -a /etc/incron.allow

Then edit the incrontab with:

# incrontab -e

Add in the text:

# /etc IN_MODIFY,IN_NO_LOOP /bin/etckeeper commit "[message]"

IN_NO_LOOP is a flag that waits for the commit to finish before running the next command, and prevents an infinite loop.

Where [message] could be something like "modified $#" where $# is a special incrontab wildcard expanded to the name of the file modified.

Do note that Incron is not capable of watching subdirectories. Only files within the path will be monitored. If you need subdirectories monitored, you must give them their own entry. However, commits when top-level files are modified will still commit all changes.

See: [1], [2]

Automatic push to remote repo

Warning: Pushing your etckeeper repository to a publicly accessible remote repository can expose sensitive data such as password hashes or private keys. Proceed with caution.

Whilst having a local backup in /etc/.git is a good first step, etckeeper can automatically push your changes on each commit to a remote repository such as Github.

First, login as root, then from the /etc/.git directory, add your remote Github repository:

# git remote add origin https://github.com/user/repo.git

Next, one of two hooks must be used or configured to push:

Using etckeeper provided hook

Edit the PUSH_REMOTE option in /etc/etckeeper/etckeeper.conf, with the name of the remote repository you want etckeeper to push to. For example:

PUSH_REMOTE="origin"

Multiple remote repositories can be added separated with spaces.

Through a custom hook

Create an executable file /etc/etckeeper/commit.d/40github-push:

#!/bin/sh
set -e

if [ "$VCS" = git ] && [ -d .git ]; then
  cd /etc/
  git push origin master
fi

Now each time you run your wrapper script or alias from above, changes will be automatically commited to your Github repo.

Wrapper script

If you want to track changes of a frequently executed command (e.g. command), a simple wrapper script can help to automate it. For example, create:

/usr/local/bin/checketc.sh

#!/bin/bash

etckeeper pre-install
command
etckeeper post-install

and make it executable. Alternatively, you may call the Etckeeper commands via a bash alias or function, see Bash#Aliases for more information.

Note: Before Etckeeper version 1.18.3-1 such manual wrapper script was required for Pacman integration. Now the Pacman hooks perform the commands automatically.