How to back up and restore Jenkins

A backup is a snapshot of the Jenkins data (jobs, configurations, secrets, plugins, etc.) at a given point in time. This backup can be used to:

• Restore Jenkins to a previous stable state (during disaster recovery).
• Migrate data to a new Jenkins charm instance.

Create a backup

1. Create the backup script From Backing-up/Restoring Jenkins, This script backs up the most essential files as mentioned in the article:

• The master.key file.
• Job-related files in the ./jobs, ./builds and ./workspace folders.
• Plugin-related files (.hpi and .jpi) in the ./plugins folder.

cat <<EOF > backup.sh
#!/bin/bash
export JENKINS_HOME=/var/lib/jenkins
export JENKINS_BACKUP=/mnt/backup

echo "running backup as \$(whoami) in \$(pwd)"
mkdir -p \$JENKINS_BACKUP
cp \$JENKINS_HOME/secrets/master.key \$JENKINS_BACKUP
cp -r \$JENKINS_HOME/jobs \$JENKINS_BACKUP
cp -r \$JENKINS_HOME/builds \$JENKINS_BACKUP
cp -r \$JENKINS_HOME/workspace \$JENKINS_BACKUP
mkdir -p \$JENKINS_BACKUP/plugins
cp -r \$JENKINS_HOME/plugins/*.hpi \$JENKINS_BACKUP/plugins
cp -r \$JENKINS_HOME/plugins/*.jpi \$JENKINS_BACKUP/plugins

chown -R 2000:2000 \$JENKINS_BACKUP
tar zcvf jenkins_backup.tar.gz --directory=/mnt backup
EOF

chmod +x backup.sh

2. Transfer the backup script above to the running unit of the Jenkins-k8s charm and run it

JENKINS_UNIT=jenkins-k8s/0
juju scp --container jenkins ./backup.sh $JENKINS_UNIT:/backup.sh
juju ssh  --container jenkins $JENKINS_UNIT /backup.sh

3. Retrieve the compressed backup file

JENKINS_UNIT=jenkins-k8s/0
juju scp --container jenkins $JENKINS_UNIT:/jenkins_backup.tar.gz jenkins_backup.tar.gz

You now have the compressed Jenkins data on your host system.

Restore the backup on a new (or existing) charm instance

1. Restore the backup on the Jenkins charm unit.

JENKINS_UNIT=jenkins-k8s/0
juju scp --container jenkins ./jenkins_backup.tar.gz $JENKINS_UNIT:/jenkins_backup.tar.gz
juju ssh --container jenkins $JENKINS_UNIT tar zxvf jenkins_backup.tar.gz
juju ssh --container jenkins $JENKINS_UNIT chown -R jenkins:jenkins /backup
juju ssh --container jenkins $JENKINS_UNIT cp -avR /backup/* /var/lib/jenkins
juju ssh --container jenkins $JENKINS_UNIT rm -rf /backup /jenkins_backup.tar.gz

2. Restart Pebble for the changes to take effect.

juju ssh --container jenkins $JENKINS_UNIT pebble restart jenkins