### Problem to solve Auto DevOps offers an [incremental rollout](https://docs.gitlab.com/ee/topics/autodevops/#incremental-rollout-to-production-premium) feature which uses GitLab CI. Customers who are not using Auto DevOps could achieve the same functionality by: 1. Defining incremental stages in the `gitlab-ci.yml` (mimicking auto devops https://gitlab.com/gitlab-org/gitlab-ce/blob/master/lib/gitlab/ci/templates/Auto-DevOps.gitlab-ci.yml#L60) 2. Define `$INCREMENTAL_ROLLOUT_MODE` and `$INCREMENTAL_ROLLOUT_ENABLED` as environment variables However, this is not documented outside of Auto DevOps. ### Further details <!-- * Any concepts, procedures, reference info we could add to make it easier to successfully use GitLab? * Include use cases, benefits, and/or goals for this work. * If adding content: What audience is it intended for? (What roles and scenarios?) For ideas, see personas at https://design.gitlab.com/research/personas or the persona labels at https://gitlab.com/groups/gitlab-org/-/labels?utf8=%E2%9C%93&subscribed=&search=persona%3A --> ### Proposal Document something along the lines of: How to perform incremental rollouts with GitLab CI ### Who can address the issue We'll need some CI experts, not sure who would be best but perhaps @jlenny can point us in the right direction ### Other links/references <!-- E.g. related GitLab issues/MRs -->