GitLab integrates with multiple third-party services to allow external issue trackers and external authentication.
See the documentation below for details on how to configure these services.
GitLab Enterprise Edition contains advanced Jenkins support.
Integration with services such as Campfire, Flowdock, Gemnasium, HipChat, Pivotal Tracker, and Slack are available in the form of a Project Service.
When trying to integrate GitLab with services that are using self-signed certificates, it is very likely that SSL certificate errors will occur on different parts of the application, most likely Sidekiq. There are 2 approaches you can take to solve this:
OS main trusted chain
This resource has all the information you need to add a certificate to the main trusted chain.
This answer at Super User also has relevant information.
Omnibus Trusted Chain
Install the self signed certificate or custom certificate authorities in to GitLab Omnibus.
It is enough to concatenate the certificate to the main trusted certificate however it may be overwritten during upgrades:
cat jira.pem >> /opt/gitlab/embedded/ssl/certs/cacert.pem
After that restart GitLab with:
sudo gitlab-ctl restart