Arvados

The Ansible installer needs to be able to install arbitrary versions of PostgreSQL in order to match, e.g., the database deployed with RDS. postgresql.org publishes packages we can use to do this. Users will configure this using two variables across our roles:

# Can name a version number like 15, 17, etc.
arvados_postgresql_version: null
# Can be either "distro" or "postgresql" 
arvados_postgresql_repository: distro

Add a role distro_postgresql that:

• depends on distro_apt
• when: "arvados_postgresql_repository == 'postgresql'", it uses @deb822_repository to set up the postgresql.org package repository and notifies the apt update handler from distro_apt
• otherwise it's a noop
• It is a dependency of arvados_postgresql and arvados_api (where we install the client packages)

In arvados_postgresql:

• Remove the separate, older arvados_postgresql_package default
• In the tasks, install postgresql-{{ arvados_postgresql_version }} if the variable is set, else just postgresql.

In arvados_api_server, add a task before Install arvados-api-server that says when: "arvados_postgresql_version is truthy", install the postgresql-client-{{ arvados_postgresql_version }} package.

Test the new code with arvados_postgresql_repository set to both distro and postgresql.