.. title:: Database

Database
===========
Kasm uses Postgres as the backend database. This section covers backup and restoration of the Kasm database.

Backups
---------
The following script will backup the Postgres data and all conf files to a single file.

.. code-block:: Bash

  # this will place the back at /tmp/backup.tar
  sudo docker exec kasm_db pg_dump -U kasmapp -F t kasm > /tmp/backup.tar

.. hint::

  This can be scripted out in a cron job, for example daily, with the date in the filename of the tar file for historical backups. Change the /tmp to a directory that is using an NFS mount so the files are stored off the server.

Restore
---------
The following script will restore the database from backup. This example assumes the server is just the datebase role, however, this process will work just as well on a system where all roles are installed.

.. code-block:: Bash

  # download the same version of kasm that is on the primary database server and unpack it
  tar -xf kasm_release*.tar.gz
  # install just the database component
  sudo bash kasm_release/install.sh -b
  # copy the backup.tar into the kasm_db container
  sudo docker cp backup.tar kasm_db:/tmp/backup.tar
  # restore the database
  sudo docker exec kasm_db pg_restore -d kasm /tmp/backup.tar -c -U kasmapp

.. warning::

  If you restore to a different server you will need to change the database IP or hostname that is referenced by all API and Manager systems. You can avoid this using several methods. Use a hostname and change the IP address in your DNS record. This may take up to an hour to propogate depending on the TTL setting of the DNS record. Use a 5 minute TTL if possible. The other method is to use a virtual IP address if you have a router or firewall inbetween your database servers and the manager/api components. Finally, you can use NGINX with layer 4 load balancing. You can back one backend server as back in the upstream definition in nginx.