PostgreSQL will not start after running cpanel-elevate

Symptoms

PostgreSQL will not start after upgrading to version 10. Using systemctl to check the status will show entries similar to the following.

Dec 27 19:07:46 server.domain.tld postgresql-check-db-dir[1593975]: An old version of the database format was found.
Dec 27 19:07:46 server.domain.tld postgresql-check-db-dir[1593975]: Use 'postgresql-setup --upgrade' to upgrade to version '10'

Description

ELevate will upgrade the PostgreSQL service, but will not attempt to upgrade the PostgreSQL database due to the possibility of data loss. The PostgreSQL database must be manually upgraded.

Workaround

1. Access the server's command line as the 'root' user via SSH or "Terminal" in WHM.
2. Open /var/lib/pgsql/data/postgresql.conf in your preferred text editor.
3. Replace unix_socket_directories with unix_socket_directory.
4. Save the changes and exit the text editor.
5. Upgrade the PostgreSQL database.

   postgresql-setup --upgrade

6. Restart PostgreSQL.

   /usr/local/cpanel/scripts/restartsrv_postgresql

Additional resources

Known cPanel ELevate Blockers: PostgreSQL database directory