Backup

MAAS doesn't yet include specific tools to help with the backup and restoration of a working MAAS environment. As MAAS servers are obviously no different to the majority of other Linux-based servers, it's likely your current backup and disaster recovery solution will already include your MAAS environment.

However, as it's important to know which elements of MAAS are critical when restoring a previous deployment, we're going to briefly outline the process and its requirements below.

Configuration files

The following MAAS components on each region and rack controller need to be backed-up and restored to recreate a working environment:

  1. The PostgreSQL database
  2. The configuration files in /etc/maas
  3. The configuration files in /var/lib/maas

/var/lib/maas/boot-resources can safely be excluded as this contains images easily re-downloaded within MAAS.

Other configuration files, such as those used by your network configuration (/etc/network/interfaces, for example) will need to be backed-up and restored according to your specific deployment requirements.

PostgreSQL export

This procedure assumes the region and rack controllers are on the same machine, that MAAS is installed on Ubuntu 16.04 LTS (Xenial) and restoration will be to identical hardware, including the network configuration.

To backup your PostgreSQL database to a file called dump.sql in your home directories, enter the following:

sudo -u postgres pg_dumpall -c > ~/dump.sql

If you run the above pg_dumpall process in the background, you can ensure this has completed and that there are no other established sessions with the following command:

sudo -u postgres psql -c  "SELECT * FROM pg_stat_activity"

Running sessions, such as pg_dumpall, will appear in the application_name column of the output alongside psql running the above pg_stat_activity query. Excepting psql, if application_name is empty you can safely stop the database service.

Stop critical services

To avoid conflicting updates during a backup, stop the following services with the sudo systemctl stop <service> command:

  • postgresql.service
  • maas-dhcpd.service
  • maas-rackd.service
  • maas-regiond.service

Note: Ubuntu 14.04 LTS (Trusty) users need to use Upstart's service command rather than Systemd's systemctl command for managing services.

Archive configuration files

Archive the database and the required configuration files with a command similar to the following:

sudo tar -cvpzf ~/backup.tgz /etc/maas /var/lib/maas ~/dump.sql

Make sure you move the resulting backup.tgz to some external storage you can access when restoring the system.

We've now backed-up all the components necessary to recreate a MAAS deployment, which we'll cover now.

Restore files

With a fresh and updated installation of Ubuntu on identical hardware, where MAAS has already been installed (sudo apt install maas), stop the following services (PostgreSQL needs to stay running):

  • maas-dhcpd.service
  • maas-rackd.service
  • maas-regiond.service

Copy the backup file to the new machine and untar its contents (sudo tar xvzpf backup.tgz).

To restore the state of the database, enter the following from the backup directory:

sudo -u postgres psql -f dump.sql postgres

Next, copy across the old configuration files to their new locations, taking care to move the originals aside just in case:

sudo mv /etc/maas /etc/_maas; mv /var/lib/maas /var/lib/_maas
sudo cp -prf etc/maas /etc/; cp -prf var/lib/maas /var/lib/

Note: Ensure the correct permissions are preserved when restoring files and directories.

If you have additional stand-alone rack controllers and a fresh installation has regenerated the /var/lib/maas/secret file, you'll need to make sure this secret is updated on each rack controller to allow them to re-connect to the newly restored region controller.

Now either restart your system(s) or the stopped services. You'll find your MAAS deployment fully restored.