Etckeeper

Intro

Etckeeper (also at https://github.com/joeyh/etckeeper) is a great tool created by Joey Hess to use your favorite VCS to keep track of what's going on in /etc.

TLDR

sudo su -
apt-get install etckeeper
cd /etc/
# change VCS to 'git' by commenting out bzr; and uncomment git
vim etckeeper/etckeeper.conf
# add the contents below to etckeeper/commit.d/20mirror-outside-files
# and make it executable
chmod a+x etckeeper/commit.d/20mirror-outside-files
# create your repo
etckeeper init
# commit your files
etckeeper commit
# now everything should just happen automagically anytime something in etc changes

Extending etckeeper

Say you want to keep track of changes to the configuration directory or file of some app. You also want to make it automatic and painless. Etckeeper leverages the commit hook in git to create that mirror. So, for example, the most critical aspect of your wiki is the LocalSettings.php configuration file. You don't want to commit the file to the version control of the project because it would expose sensitive data. etckeeper can be used to track changes to any file on the filesystem, but it's done discretely on the host.

git repos in the directories you want to track can cause problems. One useful addition is to filter out anything found in '.gitignore' per the discussion at https://stackoverflow.com/questions/13713101/rsync-exclude-according-to-gitignore-hgignore-svnignore-like-filter-c Or, since this script is just using rsync, you can add your own special cases as rsync calls

vi /etc/etckeeper/commit.d/20mirror-outside-files

#!/bin/sh
set -e

# Greg Rundlett info@equality-tech.com
# based on code from http://serverfault.com/questions/211425

# If you want other configuration data or files on the system also
# opportunistically tracked via etckeeper, use this script to copy them in.

# If there is a hook of some sort available related to the files
# you're mirroring, (e.g. Apache restart) 
# you can call etckeeper directly and track them
# proactively, rather than just opportunistically here.

MIRROR_ROOT=/etc/etckeeper.mirror.d
echo "etckeeper: mirroring outside files to $MIRROR_ROOT/:"

mirror_dir() {
   LOCAL_PATH=$1
   echo "  $LOCAL_PATH"
   mkdir -p $MIRROR_ROOT/$LOCAL_PATH
   rsync -a --filter=':- .gitignore' $LOCAL_PATH/ $MIRROR_ROOT/$LOCAL_PATH
}

mirror_file() {
   LOCAL_PATH=$1
   DIRPATH=`dirname $LOCAL_PATH`
   echo "  $LOCAL_PATH"
   mkdir -p $MIRROR_ROOT/$DIRPATH
   rsync -a $LOCAL_PATH $MIRROR_ROOT/$DIRPATH
}

# special case where we don't want to mirror a sub-directory
# we could also add a dummy .gitignore to the 'bin' directory
rsync -a --exclude=ansible/ /home/greg/bin/ $MIRROR_ROOT/home/greg/bin/

###########################################
## ADD lines below to invoke the system ###
###########################################

mirror_file "/var/www/html/wiki/LocalSettings.php"
mirror_dir "/home/greg/data"
## Special case handled above
## mirror_dir "/home/greg/bin"

Problems with Hard-linked files

I got this with a recent yum install

etckeeper warning: hardlinked files could cause problems with git: 
./fail2ban/action.d/badips.pyc
./fail2ban/action.d/badips.pyo
./fail2ban/action.d/smtp.pyc
./fail2ban/action.d/smtp.pyo

I looked at the .gitignore in /etc and .pyo and .pyc files are already ignored, so there is no problem. In fact, you can verify that git is NOT tracking these files in etc with the following:

git ls-files fail2ban | grep py

and compare to actual directory contents ls -al /etc/fail2ban

# What files am I intentionally ignoring with .gitignore?

git ls-files --other --ignored --exclude-standard

# same as

git status --ignored

Version Control System