Remove services
​​​sudo gitlab-ctl uninstall​​

Clean any data generated by usage of the package
​​​sudo gitlab-ctl cleanse​​

You may also want to remove any accounts you configured. To do so
​​​sudo gitlab-ctl remove-accounts​​

Then remove the package using
​​​sudo dpkg -P gitlab-ce​​

Furthermore, gitlab-ce uses these directories (as described ​​here 1.4k​​)

/opt/gitlab holds application code for GitLab and its dependencies.

/var/opt/gitlab holds application data and configuration files that gitlab-ctl reconfigure writes to.

/etc/gitlab holds configuration files for omnibus-gitlab. These are the only files that you should ever have to edit manually.

/var/log/gitlab contains all log data generated by components of omnibus-gitlab.

So, First remove the package recommended way (Even if you need to reinstall it). You can then remove those data using rm safely.

Information found from omnibus-gitlab ​​README page 1.4k​​