Yes, it worked. Unfortunately I did no document every step in detail, there were many steps involved. Here are they key steps, it's not a list which can be followed step-by-step, one has to figure out the details by himself:
- Export DB from old installation (mine was MariaDB)
- Start a temporary DB server on the Cloudron server and import the DB, something like:
docker run -d --name=mariadb -v mariadb-temp:/var/lib/mysql -v /tmp/dump:/data -p 3308:3306 -e MYSQL_ROOT_PASSWORD=password --network=cloudron mariadb:10.1
- Login to your Nextcloud container:
cloudron exec --app files.example.com -t bash
- Update the Nextcloud configuration to point to this temporary DB server and have the exact same version as the old installation. Example (replace values with the ones of your installation):
...
'dbtype' => 'mysql',
'version' => '13.0.0.14',
'dbname' => 'nextcloud',
'dbhost' => '172.18.0.10',
'dbport' => '3306',
'dbtableprefix' => 'oc_',
'dbuser' => 'root',
'dbpassword' => 'password',
...
sudo -u www-data php occ db:convert-type --clear-schema --all-apps --password ${POSTGRESQL_PASSWORD} pgsql ${POSTGRESQL_USERNAME} ${POSTGRESQL_HOST} ${POSTGRESQL_DATABASE}
sudo -u www-data php occ upgrade
- Move your data from the old to the new Cloudron server
- Remove temporary DB server and it's data
It's not very straight forward, but definitively doable.