gitlab-org--gitlab-foss/doc/administration/external_database.md

Configure GitLab using an external PostgreSQL service

If you're hosting GitLab on a cloud provider, you can optionally use a managed service for PostgreSQL. For example, AWS offers a managed Relational Database Service (RDS) that runs PostgreSQL.

Alternatively, you may opt to manage your own PostgreSQL instance or cluster separate from the GitLab Omnibus package.

If you use a cloud-managed service, or provide your own PostgreSQL instance:

1. Set up PostgreSQL according to the database requirements document.
2. Set up a gitlab username with a password of your choice. The gitlab user needs privileges to create the gitlabhq_production database.
3. Configure the GitLab application servers with the appropriate details. This step is covered in Configuring GitLab for HA.