Production environments are logically segregated from non-production environments.
Lesser environments must exist and be segregated, whether logially or phyiscially, from the production counterparts.
This control applies to the GitLab.com and customers.gitlab.com environments. For each, lesser environments in which development and testing occur must be logically segregated from the production environments.
Pre-production environments should be logically segregated from their production counterparts. This can be accomplished by hosted them on different hosting providers or logically segregating them by project within the same hosting provider.
Non-public information relating to this security control as well as links to the work associated with various phases of project work can be found in the Network Segmentation control issue.