mimir-distributed: allow components to override their container image

[narqo]

What this PR does

The PR updates the Helm chart to allow an individual component to override its container image reference via the component's local values. E.g.

# values.yaml

ingester:
  image:
    repository: registry.example/mimir-ingester
    tag: blah-blah

The order in which the values take precedence is:

1. take the component's local image or tag if defined
2. take the image defined in the enterprise section if enterprise is enabled
3. take the globally-defined image otherwise

Which issue(s) this PR fixes or relates to

Fixes #10237

Checklist

• Tests updated.
• Documentation added.
• CHANGELOG.md updated - the order of entries should be [CHANGE], [FEATURE], [ENHANCEMENT], [BUGFIX].
• about-versioning.md updated with experimental features.

[dimitarvdimitrov]

can you also include the keys in the values.yaml? Since we still want to use the top-level image, then you can make the new <component>.image be a comment. Something like the TSC examples

mimir/operations/helm/charts/mimir-distributed/values.yaml

Lines 873 to 883 in fc8af05

	# -- topologySpreadConstraints allows to customize the default topologySpreadConstraints. This can be either a single dict as shown below or a slice of topologySpreadConstraints.
	# labelSelector is taken from the constraint itself (if it exists) or is generated by the chart using the same selectors as for services.
	topologySpreadConstraints:
	maxSkew: 1
	topologyKey: kubernetes.io/hostname
	whenUnsatisfiable: ScheduleAnyway
	# minDomains: 1
	# nodeAffinityPolicy: Honor
	# nodeTaintsPolicy: Honor
	# matchLabelKeys:
	# - pod-template-hash

that's basically the only documentation we have of helm chart features (plus the changelog, which is barely documentation)

[dimitarvdimitrov]

i've been trying to make the changelog enough for anyone to get the gist of a change and know how to use it. Can you give an example of overriding the image for a component? Something like ingester.image.tag and ingester.image.repository. Or explain that there's an image object under all component objects now

[narqo]

I've rephrased the entry with more details about the change.

[narqo]

🆙 I've addressed the comments. PHAL

[narqo]

This one fixes the build script, so it looked for both quoted and non-quoted reference to the default image — both variants are valid to use in the YAML:

image: "grafana/mimir:

and

image: grafana/mimir:

(note the quote ")

That is, we don't want the generated manifests to have the default image, so we didn't have to re-generate them everytime the default image changes (e.g. on every weekly release).

[dimitarvdimitrov]

values.yaml being the only interface to the chart and the primary source of docs, I try to keep them as explicit as possible. You could also mention that per-component settings exist in the docs for the image and enterprise.image sections.

But I don't need to see this again. Thanks!

[dimitarvdimitrov]

ok, i may be getting annoying, but can you mention that this takes precedence over the root-level image and enterprise.image sections?

Suggested change

	# -- Allows to override the container image of the alertmanager component.
	# -- Allows to override the container image of the alertmanager component from the root-level `image` and `enterprise.image` sections.

something along those lines. You should be able to do a find-and-replace of the string.