[Feature flag] Rollout of backend Sentry feature flags
Summary
This issue holds 5 feature flags that are useful for upgrading Sentry to the >20
version without any downtime in events reporting:
configure_sentry_in_application_settings
enable_new_sentry_integration
enable_old_sentry_integration
Currently we have both Sentry clients in the application(sentry-raven
and the newer sentry-ruby
) which are controlled by the last two feature flags. Since they communicate with different Sentry backends we need to store their configurations separately, so sentry-raven
gets its config from the gitlab.rb/yml
file and sentry-ruby
uses the application settings record.
To update the config for sentry-ruby
the feature flag configure_sentry_in_application_settings
needs to enabled which allows instance administrators to navigating to Admin > Settings > Metrics and profiling > Sentry
:
These values can also be updated from a Rails console by updating the sentry related columns of the current ApplicationSetting
record:
[3] pry(main)> ApplicationSetting.column_names.grep /sentry/
=> ["sentry_enabled", "sentry_dsn", "sentry_clientside_dsn", "sentry_environment"]
Changing to the new backend version
- configure the application settings attributes for it
- set
sentry_enabled
totrue
(this won't send events withoutenable_new_sentry_integration
being enabled) - restart the application since the client is configured on application boot
- enabling
enable_new_sentry_integration
allows for exceptions to be reported to the new backend - compare the events events received by both Sentry backends(confirm that the new backend receives all of the ones that are received by the old one and that they have the same metadata)
- disable
enable_old_sentry_integration
to stop sending events to the old backend
Owners
- Team: grouppipeline execution & grouprunner
- Most appropriate slack channel to reach out to:
#g_pipeline_execution
- Best individual to reach out to:
@mbobin
,@samdbeckham
,@mrincon
- PM: NAME
Stakeholders
Expectations
What are we expecting to happen?
- Admins can configure Sentry from the UI.
- The new Sentry backend receives the same events as the old one.
What might happen if this goes wrong?
What can we monitor to detect problems with this?
Rollout Steps
Rollout on non-production environments
- Ensure that the feature MRs have been deployed to non-production environments.
-
/chatops run auto_deploy status <merge-commit-of-your-feature>
-
-
Enable the feature globally on non-production environments. -
/chatops run feature set configure_sentry_in_application_settings true --dev
-
/chatops run feature set configure_sentry_in_application_settings true --staging
-
-
Verify that the feature works as expected. Posting the QA result in this issue is preferable.
Specific rollout on production
- Ensure that the feature MRs have been deployed to both production and canary.
-
/chatops run auto_deploy status <merge-commit-of-your-feature>
-
- If you're using project-actor, you must enable the feature on these entries:
-
/chatops run feature set --project=gitlab-org/gitlab configure_sentry_in_application_settings true
-
/chatops run feature set --project=gitlab-org/gitlab-foss configure_sentry_in_application_settings true
-
/chatops run feature set --project=gitlab-com/www-gitlab-com configure_sentry_in_application_settings true
-
- If you're using group-actor, you must enable the feature on these entries:
-
/chatops run feature set --group=gitlab-org configure_sentry_in_application_settings true
-
/chatops run feature set --group=gitlab-com configure_sentry_in_application_settings true
-
- If you're using user-actor, you must enable the feature on these entries:
-
/chatops run feature set --user=<your-username> configure_sentry_in_application_settings true
-
-
Verify that the feature works on the specific entries. Posting the QA result in this issue is preferable.
Preparation before global rollout
-
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). -
Announce on the feature issue an estimated time this will be enabled on GitLab.com. -
If the feature might impact the user experience, notify #support_gitlab-com
and your team channel (more guidance when this is necessary in the dev docs).
Global rollout on production
All /chatops
commands that target production should be done in the #production
slack channel for visibility.
-
Incrementally roll out the feature. - If the feature flag in code has an actor, perform actor-based rollout.
-
/chatops run feature set configure_sentry_in_application_settings <rollout-percentage> --actors
-
- If the feature flag in code does NOT have an actor, perform time-based rollout (random rollout).
-
/chatops run feature set configure_sentry_in_application_settings <rollout-percentage>
-
- Enable the feature globally on production environment.
-
/chatops run feature set configure_sentry_in_application_settings true
-
- If the feature flag in code has an actor, perform actor-based rollout.
-
Announce on the feature issue 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
. -
Create a changelog entry.
-
-
Ensure that the default-enabling MR has been deployed to both production and canary. If the merge request was deployed before the code cutoff, the feature can be officially announced in a release blog post. -
/chatops run auto_deploy status <merge-commit-of-default-enabling-mr>
-
-
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 <feature-flag-name>
". -
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.
-
Create a merge request to remove <feature-flag-name>
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 deployed to both production and canary. If the merge request was deployed before the code cutoff, the feature can be officially announced in a release blog post. -
/chatops run auto_deploy status <merge-commit-of-cleanup-mr>
-
-
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 configure_sentry_in_application_settings --dev
-
/chatops run feature delete configure_sentry_in_application_settings --staging
-
/chatops run feature delete configure_sentry_in_application_settings
-
-
Close this rollout issue.
Rollback Steps
-
This feature can be disabled by running the following Chatops command:
/chatops run feature set configure_sentry_in_application_settings false