Enable setting to enforce two factor authentication on administrator users

Details

• Point of contact for this request: @dcouture
• If a call is needed, what is the proposed date and time of the call: I don't think a call is needed but EMEA day time works for me
• Additional call details (format, type of call): additional details

SRE Support Needed

1. Go to the admin area, Settings > General page
2. Under "Sign-in restrictions", find the checkbox "Require administrators to enable 2FA"
3. Click the checkbox

This is a new feature that was added in gitlab-org/gitlab!137911 (merged)

It's already policy at GitLab to require 2FA for all team members and we do this through the gitlab-com group but some admin accounts aren't in that group. This new setting will catch those accounts as well.