Reuse prometheus chart values when editing alerts
What does this MR do?
Alerts for the GitLab-managed app Prometheus are updated via helm.
Prior to this change, when alerts were updated, all helm values would
receive the current contents of values.yaml, with the alerts section
overridden, or falling back to the default chart values.
This meant that any time we made changes to values.yaml affecting
component versions (e.g. the versions of prometheus or alertmanager),
those would trigger a deployment of those component in the cluster,
potentially breaking the prometheus installation.
This was a very real problem, since we currently have hardcoded versions
of both prometheus server and alertmanager in values.yaml, and would
like to update the chart and remove the hardcoded versions in a single
change.
With this change, alert updates no longer take any values from
values.yaml; instead they only update alerts. We avoid reverting to
default chart values by using helm's --reuse-values flag instead of
the --reset-values flag.
See #38294 (closed)
Screenshots
Does this MR meet the acceptance criteria?
Conformity
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Availability and Testing
- [-] Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
- [-] Tested in all supported browsers
Security
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@gitlab-com/gl-security/appsec - [-] The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
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