Migrate prometheus VMs to use SSD data disks

Production Change

Change Summary

Originating Issue: https://gitlab.com/gitlab-com/gl-infra/reliability/-/issues/16827

Update the data disks for prometheus VMs in GPRD from standard to ssd disks.

Change Details

  1. Services Impacted - ServicePrometheus
  2. Change Technician - @cmcfarland
  3. Change Reviewer - @f_santos
  4. Time tracking - 120
  5. Downtime Component - N/A

Detailed steps for the change

Change Steps - steps to take to execute the change

Estimated Time to Complete (mins) - 60

  • Set label changein-progress /label ~change::in-progress
  • Merge the TF change for data disk type:
  • prometheus-01-inf-gprd.c.gitlab-production.internal
    • Stop prometheus-01-inf-gprd.c.gitlab-production.internal 
    gcloud --project gitlab-production compute instances stop prometheus-01-inf-gprd
    • Create a snapshot of the data disk.
    gcloud --project gitlab-production compute snapshots create cr8066-1 --source-disk=prometheus-01-inf-gprd-data --source-disk-zone=us-east1-c
    • Detach and delete the data disk from prometheus-01-inf-gprd.c.gitlab-production.internal 
    gcloud --project gitlab-production compute instances detach-disk prometheus-01-inf-gprd --disk=prometheus-01-inf-gprd-data --zone=us-east1-c
gcloud --project gitlab-production compute disks delete prometheus-01-inf-gprd-data --zone=us-east1-c
    • Create a new disk from the snapshot that is an SSD
    gcloud --project gitlab-production compute disks create prometheus-01-inf-gprd-data --zone=us-east1-c --size=4000 --source-snapshot=cr8066-1 --type=pd-ssd
    • Attach the new disk to prometheus-01-inf-gprd.c.gitlab-production.internal 
    gcloud --project gitlab-production compute instances attach-disk prometheus-01-inf-gprd --disk=prometheus-01-inf-gprd-data --zone=us-east1-c
    • Boot and verify the disk is mounted and prometheus is working properly.
    gcloud --project gitlab-production compute instances start prometheus-01-inf-gprd
    • Check Terraform state and import new disk.
      • Run a tf plan for GPRD.
      • Import the new disk to replace the missing disk.
      tf import "module.prometheus.google_compute_disk.default[0]" projects/gitlab-production/zones/us-east1-c/disks/prometheus-01-inf-gprd-data
      • Run a tf plan for GPRD and verify no changes expected.
    • Verify prometheus in gprd is still working https://prometheus.gprd.gitlab.net/
    • Verify that the GCP load balancer for prometheus shows the VM as healthy.
  • prometheus-02-inf-gprd.c.gitlab-production.internal
    • Stop prometheus-02-inf-gprd.c.gitlab-production.internal 
    gcloud --project gitlab-production compute instances stop prometheus-02-inf-gprd
    • Create a snapshot of the data disk.
    gcloud --project gitlab-production compute snapshots create cr8066-2 --source-disk=prometheus-02-inf-gprd-data --source-disk-zone=us-east1-d
    • Detach and delete the data disk from prometheus-02-inf-gprd.c.gitlab-production.internal 
    gcloud --project gitlab-production compute instances detach-disk prometheus-02-inf-gprd --disk=prometheus-02-inf-gprd-data --zone=us-east1-d
gcloud --project gitlab-production compute disks delete prometheus-02-inf-gprd-data --zone=us-east1-d
    • Create a new disk from the snapshot that is an SSD
    gcloud --project gitlab-production compute disks create prometheus-02-inf-gprd-data --zone=us-east1-d --size=4000 --source-snapshot=cr8066-2 --type=pd-ssd
    • Attach the new disk to prometheus-02-inf-gprd.c.gitlab-production.internal 
    gcloud --project gitlab-production compute instances attach-disk prometheus-02-inf-gprd --disk=prometheus-02-inf-gprd-data --zone=us-east1-d
    • Boot and verify the disk is mounted and prometheus is working properly.
    gcloud --project gitlab-production compute instances start prometheus-02-inf-gprd
    • Check Terraform state and import new disk.
      • Run a tf plan for GPRD.
      • Import the new disk to replace the missing disk.
      tf import "module.prometheus.google_compute_disk.default[1]" projects/gitlab-production/zones/us-east1-d/disks/prometheus-02-inf-gprd-data
      • Run a tf plan for GPRD and verify no changes expected.
    • Verify prometheus in gprd is still working https://prometheus.gprd.gitlab.net/
    • Verify that the GCP load balancer for prometheus shows the VM as healthy.
  • Set label changecomplete /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) - 60

  • The only known rollback is probably to rebuilt the VM that is lost. Or to restore the snapshot to a standard disk.
  • Set label changeaborted /label ~change::aborted

Monitoring

Key metrics to observe

  • Metric: Metric Name
    • Location: Dashboard URL
    • What changes to this metric should prompt a rollback: Describe Changes

Change Reviewer checklist

C4 C3 C2 C1:

  • Check if the following applies:
    • The scheduled day and time of execution of the change is appropriate.
    • The change plan is technically accurate.
    • The change plan includes estimated timing values based on previous testing.
    • The change plan includes a viable rollback plan.
    • The specified metrics/monitoring dashboards 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 labels blocks deployments and/or blocks feature-flags are applied as necessary

Change Technician checklist

  • Check if all items below are complete:
    • The change plan is technically accurate.
    • This Change Issue is linked to the appropriate Issue and/or Epic
    • Change has been tested in staging and results noted in a comment on this issue.
    • A dry-run has been conducted and results noted in a comment on this issue.
    • The change execution window respects the Production Change Lock periods.
    • For C1 and C2 change issues, the change event is added to the GitLab Production calendar.
    • For C1 and C2 change issues, the SRE on-call has been informed prior to change being rolled out. (In #production channel, mention @sre-oncall and this issue and await their acknowledgement.)
    • For C1 and C2 change issues, the SRE on-call provided approval with the eoc_approved label on the issue.
    • For C1 and C2 change issues, the Infrastructure Manager provided approval with the manager_approved label on the issue.
    • Release managers have been informed (If needed! Cases include DB change) prior to change being rolled out. (In #production channel, mention @release-managers and this issue and await their acknowledgment.)
    • There are currently no active incidents that are severity1 or severity2
    • 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.
Edited by Cameron McFarland