We used to operate our local GitLab instance with a self-signed certificate at
gitlab was the hostname of the server), which was accessible from our internal network.
Due to a new requirement to make the instance accessible from our external servers (and to get rid of the occasional issues that come with the self-signed certificate), we wanted to migrate from
Basically this worked easily by changing the
external_url accordingly and
gitlab-ctl reconfigure && gitlab-ctl restart.
However this broke old links starting with
https://gitlab/..., because GitLab presented the new certificate for
gitlab.example.com, which was of course refused by the browser.
(I will post the solution in a second.)