<!-- Please review https://handbook.gitlab.com/handbook/engineering/infrastructure-platforms/change-management/ for the most recent information on our change plans and execution policies. --> # Production Change ## Change Summary The default IP range for pods in each production cluster is a /16, allowing a max of 256 nodes because they are each allocated a /24 CIDR block within this range. We hit that limit recently, resulting in scale-up errors because of `Insufficient free IP addresses in the IP range '10.68.0.0/16`. We can't extend the IP range without rebuilding the clusters, but we can add additional ones. This change is very low risk: clusters are updated in place, the existing IP ranges and running nodes will not be affected. If for some reason the new IP ranges are not working, the new nodes trying to use them won't be able to become healthy and run any workload pods. Docs: https://docs.cloud.google.com/kubernetes-engine/docs/how-to/multi-pod-cidr Related issue: https://gitlab.com/gitlab-com/gl-infra/production-engineering/-/work_items/28432 ## Change Details <!-- To automatically add your change to the GitLab Production calendar update the following fields: - Time tracking - Scheduled Date and Time (UTC in format YYYY-MM-DD HH:MM) Bot: https://gitlab.com/gitlab-com/gl-infra/ops-team/toolkit/change-scheduler --> 1. **Services Impacted** - ~"Service::Kube" 1. **Change Technician** - `@pguinoiseau` 1. **Change Reviewer** - @nduff @cmcfarland 1. **Scheduled Date and Time (UTC in format YYYY-MM-DD HH:MM)** - 2026-03-03 03:00 1. **Time tracking** - 10 minutes 1. **Downtime Component** - none > [!IMPORTANT] > If your change involves scheduled maintenance, add a step to set and > [unset maintenance mode](https://gitlab.com/gitlab-com/runbooks/-/blob/master/docs/monitoring/set_maintenance_window.md) > per our runbooks. This will make sure SLA calculations adjust for the maintenance period. ## Preparation > [!NOTE] > The following checklists must be done in advance, before setting the label ~"change::scheduled" ### Change Reviewer checklist <!-- To be filled out by the reviewer. --> ~C4 ~C3 ~C2 ~C1: - [ ] Check if the following applies: - The **scheduled day and time** of execution of the change is appropriate. - The [change plan](#detailed-steps-for-the-change) is technically accurate. - The change plan includes **estimated timing values** based on previous testing. - The change plan includes a viable [rollback plan](#rollback). - The specified [metrics/monitoring dashboards](#key-metrics-to-observe) provide sufficient visibility for the change. ~C2 ~C1: - [ ] Check if the following applies: - The complexity of the plan is appropriate for the corresponding risk of the change. (i.e. the plan contains clear details). - The change plan includes success measures for all steps/milestones during the execution. - The change adequately minimizes risk within the environment/service. - The performance implications of executing the change are well-understood and documented. - The specified metrics/monitoring dashboards provide sufficient visibility for the change. - If not, is it possible (or necessary) to make changes to observability platforms for added visibility? - The change has a primary and secondary SRE with knowledge of the details available during the change window. - The change window has been agreed with Release Managers in advance of the change. If the change is planned for APAC hours, this issue has an agreed pre-change approval. - The labels ~"blocks deployments" and/or ~"blocks feature-flags" are applied as necessary. ### Change Technician checklist - [x] The [Change Criticality](https://handbook.gitlab.com/handbook/engineering/infrastructure-platforms/change-management/#change-criticalities) has been set appropriately and requirements have been reviewed. - [x] The [change plan](#detailed-steps-for-the-change) is technically accurate. - [x] The [rollback plan](#rollback) is technically accurate and detailed enough to be executed by anyone with access. - [x] This Change Issue is linked to the appropriate Issue and/or Epic - [x] Change has been tested in staging and results noted in a comment on this issue. - [x] A dry-run has been conducted and results noted in a comment on this issue. - [x] The change execution window respects the [Production Change Lock periods](https://about.gitlab.com/handbook/engineering/infrastructure/change-management/#production-change-lock-pcl). - [x] Once all boxes above are checked, mark the change request as scheduled: `/label ~"change::scheduled"` - [x] For ~C1 and ~C2 change issues, the change event is added to the [GitLab Production](https://calendar.google.com/calendar/embed?src=gitlab.com_si2ach70eb1j65cnu040m3alq0%40group.calendar.google.com) calendar by the [change-scheduler bot](https://gitlab.com/gitlab-com/gl-infra/ops-team/toolkit/change-scheduler). It is schedule to run every 2 hours. - [x] For ~C1 and ~C2 change issues, Platform Leadership provides approval with the ~platform_leadership_approved label on the issue. Mention `@gitlab-org/saas-platforms/change-review-leadership` in this issue with a reference to [review guidelines](https://handbook.gitlab.com/handbook/engineering/infrastructure-platforms/change-management/platform-leadership-review/) to get approval and provide visibility to all infrastructure managers. - [ ] For ~C1, ~C2, or ~"blocks deployments" change issues, confirm with Release managers that the change does not overlap or hinder any release process (In `#production` channel, mention `@release-managers` and this issue and await their acknowledgment.) - [ ] For ~C1 change issues or ~C2 change issues happening during weekend, SREs on-call must be informed [at least 2 weeks in advance](https://handbook.gitlab.com/handbook/engineering/infrastructure-platforms/change-management/#approval). Check [the incident.io GitLab.com Production EOC schedule](https://app.incident.io/gitlab/on-call/schedules/01K5YWAGZ7YCQGAG7ATQ9XQWHW) to find who will be on-call at the scheduled day and time. ## Detailed steps for the change ### Pre-execution steps > [!NOTE] > The following steps should be done right at the scheduled time of the change request. The [preparation steps](#preparation) are > listed below. - [x] Make sure all tasks in [Change Technician checklist](#change-technician-checklist) are done - [x] For ~C1 and ~C2 change issues, the SRE on-call has been informed prior to change being rolled out. - [x] The SRE on-call provided approval with the ~eoc_approved label on the issue. - [ ] For ~C1, ~C2, or ~"blocks deployments" change issues, Release managers have been informed prior to change being rolled out. (In `#production` channel, mention `@release-managers` and this issue and await their acknowledgment.) - [x] There are currently no [active incidents](https://gitlab.com/gitlab-com/gl-infra/production/-/issues/?sort=created_date&state=opened&label_name%5B%5D=Incident%3A%3AActive&or%5Blabel_name%5D%5B%5D=severity%3A%3A1&or%5Blabel_name%5D%5B%5D=severity%3A%3A2&first_page_size=20) that are ~severity::1 or ~severity::2 - [ ] If the change involves doing maintenance on a database host, an appropriate silence targeting the host(s) should be added for the duration of the change. ### Change steps - steps to take to execute the change *Estimated Time to Complete (mins)* - 5 minutes - [x] Set label ~"change::in-progress" `/label ~change::in-progress` - [x] Apply and merge https://ops.gitlab.net/gitlab-com/gl-infra/config-mgmt/-/merge_requests/13329 - [x] Set label ~"change::complete" `/label ~change::complete` ## Rollback ### Rollback steps - steps to be taken in the event of a need to rollback this change *Estimated Time to Complete (mins)* - 5 minutes - [ ] Revert https://ops.gitlab.net/gitlab-com/gl-infra/config-mgmt/-/merge_requests/13329 - [ ] Set label ~"change::aborted" `/label ~change::aborted` ## Monitoring ### Key metrics to observe <!-- * Describe which dashboards and which specific metrics we should be monitoring related to this change using the format below. --> - Metric: `cluster_scaleups` SLI Error Ratio - Location: https://dashboards.gitlab.net/d/kube-main/kube3a-overview - What changes to this metric should prompt a rollback: increase in error ratio