If you ever decide to downgrade your Enterprise Edition back to the Community Edition, there are a few steps you need take before installing the CE package on top of the current EE package, or, if you are in an installation from source, before you change remotes and fetch the latest CE code.
First thing to do is to disable the following features.
Kerberos and Atlassian Crowd are only available on the Enterprise Edition, so you should disable these mechanisms before downgrading and you should provide alternative authentication methods to your users.
Git Annex is also only available on the Enterprise Edition. This means that if you have repositories that use Git Annex to store large files, these files will no longer be easily available via Git. You should consider migrating these repositories to use Git LFS before downgrading to the Community Edition.
JenkinsService class is only available on the Enterprise Edition codebase, so if you downgrade to the Community Edition, you'll come across the following error:
Completed 500 Internal Server Error in 497ms (ActiveRecord: 32.2ms) ActionView::Template::Error (The single-table inheritance mechanism failed to locate the subclass: 'JenkinsService'. This error is raised because the column 'type' is reserved for storing the class in case of inheritance. Please rename this column if you didn't intend it to be used for storing the inheritance class or overwrite Service.inheritance_column to use another column for that information.)
All services are created automatically for every project you have, so in order to avoid getting this error, you need to remove all instances of the
JenkinsService from your database:
$ sudo gitlab-rails runner "Service.where(type: ['JenkinsService', 'JenkinsDeprecatedService']).delete_all"
$ bundle exec rails runner "Service.where(type: ['JenkinsService', 'JenkinsDeprecatedService']).delete_all" production
After performing the above mentioned steps, you are now ready to downgrade your GitLab installation to the Community Edition.
To downgrade an Omnibus installation, it is sufficient to install the Community Edition package on top of the currently installed one. You can do this manually, by directly downloading the package you need, or by adding our CE package repository and following the CE installation instructions.
To downgrade a source installation, you need to replace the current remote of your GitLab installation with the Community Edition's remote, fetch the latest changes, and checkout the latest stable branch:
$ git remote set-url origin [email protected]:gitlab-org/gitlab-ce.git $ git fetch --all $ git checkout 8-x-stable
Remember to follow the correct update guides to make sure all dependencies are up to date.