Provide configuration to override Geo sync URL

Description

By default the GitLab Geo secondary node uses the external_url from the primary node for cloning repositories (see ssh_url_to_repo)

This can cause issues if the user wishes to use a different URL to clone (sync) from, for example a hostname instead of the FQDN (external_url).

Proposal

Provide an additional advanced configuration option to override the Geo SSH or HTTP clone URL.

UI Example

gitlab.rb example

geo_secondary['primary_clone_url'] = 'hostname'

Use cases

This use case applies to instances behind a proxy that blocks port 22. Cloning is only available via HTTPS

Example 1: Non-working example

Example 2: Working example

Currently as only the external_url can be used the Geo secondary node cannot connect directly via gitlab-primary.local and must connect via gitlab-public.example.com

Links / references

• https://gitlab.zendesk.com/agent/tickets/78858

cc @stanhu @dbalexandre