How to upgrade Gitlab safely with zero downtime

GitLab is a complex piece of software. If you are planning on upgrading your self-hosted GitLab machine to a new major version, you need to follow this documentation: https://docs.gitlab.com/ee/update/

Also, use the Upgrade Path Toolbox from here: https://gitlab-com.gitlab.io/support/toolbox/upgrade-path/?edition=ce to ensure that the upgrade is smooth and safe.

For instance, if you currently have gitlab-ce version 15.11.10-ce.0 and want to upgrade to version 16.10.1, you have to perform the following upgrade one-by-one:

• apt-get install gitlab-ce=15.11.13-ce.0
• apt-get install gitlab-ce=16.0.8-ce.0
• apt-get install gitlab-ce=16.1.6-ce.0
• apt-get install gitlab-ce=16.2.9-ce.0
• apt-get install gitlab-ce=16.3.7-ce.0
• apt-get install gitlab-ce=16.4.5-ce.0
• apt-get install gitlab-ce=16.5.8-ce.0
• apt-get install gitlab-ce=16.6.7-ce.0
• apt-get install gitlab-ce=16.7.7-ce.0
• apt-get install gitlab-ce=16.8.5-ce.0
• apt-get install gitlab-ce=16.9.3-ce.0
• apt-get install gitlab-ce=16.10.1-ce.0

See - https://gitlab-com.gitlab.io/support/toolbox/upgrade-path/?current=15.11.10&edition=ce&downtime=true