Manage Configuration Changes with Git

This content was originally written on the OpenNMS Discourse forum (see Managing Configuration Changes with Git).

If you want to manage your configuration files with Git but haven’t used it for version control before, GitHub’s Using Git tutorial covers the basics. You can also read Developing with Git on the OpenNMS Discourse forum.

If you have an existing OpenNMS Horizon installation, check for the etc-pristine directory. If your Horizon environment does not have this directory, you will need to upgrade to a version that does.

Remember to stop Horizon before changing files in the etc-pristine directory.

Start with a pristine etc directory

  • Debian OSes

  • Other OSes

$OPENNMS_HOME/etc is linked to /etc/opennms. Do not move that folder. Moving the folder will break the link and cause future upgrades to fail.

Run the following code to prevent breaking the link between folders:

cd /usr/share/opennms
mv etc etc_bad
ln -s /etc/opennms etc

Run the following code to move your customized configuration files to /etc/opennms.bak and replace them with the contents of etc-pristine:

mv /etc/opennms /etc/opennms.bak
cp -pR /usr/share/opennms/share/etc-pristine /etc/opennms

Run the following code to move your $OPENNMS_HOME/etc files to a safe place, then copy etc-pristine to the $OPENNMS_HOME/etc directory:

cp -pR $OPENNMS_HOME/share/etc-pristine $OPENNMS_HOME/etc
On RPM-based installations, the pristine configuration files are located in $OPENNMS_HOME/share/etc-pristine.

Initialize Git

Run the code below to turn your etc directory into a Git repository and add the pristine files as your first commit:

git init
cat << EOF > $OPENNMS_HOME/etc/.gitignore
git add .
git commit -m "Initial checkin of OpenNMS x.x.x configuration."

Replace the x.x.x in the last line with your current Horizon version.

Create branch

Run the code below to create a new branch in your repository:

git branch local-modifications
git checkout local-modifications

Make changes

You can now edit your configuration files as you normally would. If you previously backed up your modified configuration files, you can run this code to restore them:

rsync -avr $OPENNMS_HOME/etc.bak/ $OPENNMS_HOME/etc/

Any time you want to save your changes to the etc directory, run this code to commit them to the branch you created (in this case, local-modifications):

git add .
git commit -m "Added initial discovery ranges."

When you are finished modifying your configuration files, you can start Horizon.