[Feature flag] Rollout of `generate_ci_finished_builds_sync_events` and `ci_data_ingestion_to_click_house`
Summary
This issue is to rollout the feature on production,
that is currently behind the generate_ci_finished_builds_sync_events
and ci_data_ingestion_to_click_house
feature flags.
Owners
- Team: Runner Fleet
- Most appropriate slack channel to reach out to:
#f_runner_fleet_management
- Best individual to reach out to:
@pedropombeiro
@vshushlin
- PM:
@DarrenEastman
Stakeholders
Expectations
What are we expecting to happen?
- Once we enable
generate_ci_finished_builds_sync_events
, we should start seeing new records be created in thep_ci_finished_build_ch_sync_events
table in theci
database. These act as a queue for the next FF logic. - If ClickHouse is set up on staging and production and the
ci_data_ingestion_to_click_house
FF is enabled then the job will start syncingci_builds
data to ClickHouse for finished builds signaled inp_ci_finished_build_ch_sync_events
.
When is the feature viable?
When we can sync data in a timely manner to ClickHouse.
What might happen if this goes wrong?
generate_ci_finished_builds_sync_events FF
- Increased load on Postgres
ci_data_ingestion_to_click_house FF
-
Increased load on Postgres
-
Higher data-lag in ClickHouse
-
Increasing backlog of unprocessed records in
p_ci_finished_build_ch_sync_events
over at least 15 minutes:SELECT processed, COUNT(*) FROM p_ci_finished_build_ch_sync_events GROUP BY processed;
In this case, we could increase the number of workers spawned by the cron job by increasing the
total_workers
argument to theclick_house_ci_finished_builds_sync_worker
worker. -
We should ensure that not only the cron workers are able to keep up with the number of finished builds being created, but that we also have some headroom. In order to check for that, we could look at the worker result values in the Sidekiq logs, and see if
reached_end_of_table
is regularly true. If not, we'll want to increase the number of workers.
What can we monitor to detect problems with this?
Consider mentioning checks for 5xx errors or other anomalies like an increase in redirects (302 HTTP response status)
What can we check for monitoring production after rollouts?
Consider adding links to check for Sentry errors, Production logs for 5xx, 302s, etc.
-
Sidekiq logs related to
ClickHouse::CiFinishedBuildsSyncCronWorker
andClickHouse::CiFinishedBuildsSyncWorker
. -
Increased load on Postgres.
-
Increasing backlog of unprocessed records in
p_ci_finished_build_ch_sync_events
over at least 15 minutes:SELECT processed, COUNT(*) FROM p_ci_finished_build_ch_sync_events GROUP BY processed;
Rollout Steps
Note: Please make sure to run the chatops commands in the slack channel that gets impacted by the command.
Rollout on non-production environments
-
Verify the MR with the feature flag is merged to master. - Verify that the feature MRs have been deployed to non-production environments with:
-
/chatops run auto_deploy status https://gitlab.com/gitlab-org/gitlab/-/issues/421201
-
-
Enable the feature globally on non-production environments. -
/chatops run feature set generate_ci_finished_builds_sync_events true --dev --staging --staging-ref
-
/chatops run feature set ci_data_ingestion_to_click_house true --dev --staging --staging-ref
- If the feature flag causes QA end-to-end tests to fail:
-
Disable the feature flag on staging to avoid blocking deployments.
-
-
-
Verify that the feature works as expected. Posting the QA result in this issue is preferable. The best environment to validate the feature in is staging-canary as this is the first environment deployed to. Note you will need to make sure you are configured to use canary as outlined here when accessing the staging environment in order to make sure you are testing appropriately.
For assistance with QA end-to-end test failures, please reach out via the #quality
Slack channel. Note that QA test failures on staging-ref don't block deployments.
Specific rollout on production
For visibility, all /chatops
commands that target production should be executed in the #production
slack channel and cross-posted (with the command results) to the responsible team's slack channel (#g_TEAM_NAME
).
- Ensure that the feature MRs have been deployed to both production and canary.
-
/chatops run auto_deploy status https://gitlab.com/gitlab-org/gitlab/-/issues/421201
-
- Depending on the type of actor you are using, pick one of these options:
- If you're using project-actor, you must enable the feature on these entries:
-
/chatops run feature set --project=gitlab-org/gitlab,gitlab-org/gitlab-foss,gitlab-com/www-gitlab-com generate_ci_finished_builds_sync_events true
-
/chatops run feature set --project=gitlab-org/gitlab,gitlab-org/gitlab-foss,gitlab-com/www-gitlab-com ci_data_ingestion_to_click_house true
-
- If you're using group-actor, you must enable the feature on these entries:
-
/chatops run feature set --group=gitlab-org,gitlab-com generate_ci_finished_builds_sync_events true
-
/chatops run feature set --group=gitlab-org,gitlab-com ci_data_ingestion_to_click_house true
-
- If you're using user-actor, you must enable the feature on these entries:
-
/chatops run feature set --user=<your-username> generate_ci_finished_builds_sync_events true
-
/chatops run feature set --user=<your-username> ci_data_ingestion_to_click_house true
-
- If you're using project-actor, you must enable the feature on these entries:
-
Verify that the feature works on the specific entries. Posting the QA result in this issue is preferable.
Preparation before global rollout
-
Set a milestone to the rollout issue to signal for enabling and removing the feature flag when it is stable. -
Check if the feature flag change needs to be accompanied with a change management issue. Cross link the issue here if it does. -
Ensure that you or a representative in development can be available for at least 2 hours after feature flag updates in production. If a different developer will be covering, or an exception is needed, please inform the oncall SRE by using the @sre-oncall
Slack alias. -
Ensure that documentation has been updated (More info). -
Leave a comment on the feature issue announcing estimated time when this feature flag will be enabled on GitLab.com. -
Ensure that any breaking changes have been announced following the release post process to ensure GitLab customers are aware. -
Notify #support_gitlab-com
and your team channel (more guidance when this is necessary in the dev docs). -
Ensure that the feature flag rollout plan is reviewed by another developer familiar with the domain.
Global rollout on production
For visibility, all /chatops
commands that target production should be executed in the #production
slack channel and cross-posted (with the command results) to the responsible team's slack channel (#g_TEAM_NAME
).
-
Incrementally roll out the feature. -
Between every step wait for at least 15 minutes and monitor the appropriate graphs on https://dashboards.gitlab.net. - If the feature flag in code has an actor, perform actor-based rollout.
-
/chatops run feature set ci_data_ingestion_to_click_house <rollout-percentage> --actors
-
- If the feature flag in code does NOT have an actor, perform time-based rollout (random rollout).
-
/chatops run feature set ci_data_ingestion_to_click_house <rollout-percentage> --random
-
- Enable the feature globally on production environment.
-
/chatops run feature set ci_data_ingestion_to_click_house true
-
/chatops run feature set generate_ci_finished_builds_sync_events true
-
-
-
Observe appropriate graphs on https://dashboards.gitlab.net and verify that services are not affected. -
Leave a comment on the feature issue announcing that the feature has been globally enabled. -
Wait for at least one day for the verification term.
(Optional) Release the feature with the feature flag
If you're still unsure whether the feature is deemed stable but want to release it in the current milestone, you can change the default state of the feature flag to be enabled. To do so, follow these steps:
-
Create a merge request with the following changes. Ask for review and merge it. -
Set the default_enabled
attribute in the feature flag definition totrue
. -
Review what warrants a changelog entry and decide if a changelog entry is needed.
-
-
Ensure that the default-enabling MR has been included in the release package. If the merge request was deployed before the monthly release was tagged, the feature can be officially announced in a release blog post. -
/chatops run release check <merge-request-url> <milestone>
-
-
Consider cleaning up the feature flag from all environments by running these chatops command in #production
channel. Otherwise these settings may override the default enabled.-
/chatops run feature delete ci_data_ingestion_to_click_house --dev --staging --staging-ref --production
-
-
Close the feature issue to indicate the feature will be released in the current milestone. -
Set the next milestone to this rollout issue for scheduling the flag removal. -
(Optional) You can create a separate issue for scheduling the steps below to Release the feature. -
Set the title to "[Feature flag] Cleanup ci_data_ingestion_to_click_house
". -
Execute the /copy_metadata <this-rollout-issue-link>
quick action to copy the labels from this rollout issue. -
Link this rollout issue as a related issue. -
Close this rollout issue.
-
WARNING: This approach has the downside that it makes it difficult for us to clean up the flag. For example, on-premise users could disable the feature on their GitLab instance. But when you remove the flag at some point, they suddenly see the feature as enabled and they can't roll it back to the previous behavior. To avoid this potential breaking change, use this approach only for urgent matters.
Release the feature
After the feature has been deemed stable, the clean up should be done as soon as possible to permanently enable the feature and reduce complexity in the codebase.
You can either create a follow-up issue for Feature Flag Cleanup or use the checklist below in this same issue.
-
Create a merge request to remove ci_data_ingestion_to_click_house
feature flag. Ask for review and merge it.-
Remove all references to the feature flag from the codebase. -
Remove the YAML definitions for the feature from the repository. -
Create a changelog entry.
-
-
Ensure that the cleanup MR has been included in the release package. If the merge request was deployed before the monthly release was tagged, the feature can be officially announced in a release blog post. -
/chatops run release check <merge-request-url> <milestone>
-
-
Close the feature issue to indicate the feature will be released in the current milestone. -
Clean up the feature flag from all environments by running these chatops command in #production
channel:-
/chatops run feature delete ci_data_ingestion_to_click_house --dev --staging --staging-ref --production
-
-
Close this rollout issue.
Rollback Steps
-
This feature can be disabled by running the following Chatops command:
/chatops run feature set ci_data_ingestion_to_click_house false