[alertmanager] add new chart

[naseemkullah]

Special notes for your reviewer:

Adds a minimalist alertmanager chart.

Checklist

• DCO signed
• Chart Version bumped
• Title of the PR starts with chart name (e.g. [prometheus-couchdb-exporter])

[torstenwalter]

Did you see that AlertManager is part of https://github.com/prometheus-community/helm-charts/tree/main/charts/prometheus-operator/templates/alertmanager?

[scottrigby]

It would be good to provide some context. I happen to know from earlier conversations with @naseemkullah and @brancz that this is a step toward componentizing that chart into standalone parts. In future, the kube-prometheus-stack chart could switch to pulling this in as a dependency. Alternatively this could be installed separately with other standalone charts like prometheus.

But @naseemkullah you might have more context details.

[naseemkullah]

Use cases would indeed be for standalone chart and potentially eventual replacement of alertmanager component in prometheus chart (not prometheus-operator/kube-prometheus-stack chart though, since it is a CRD there).

[Xtigyro]

Why would anybody need a separate chart for Alertmanager?

[naseemkullah]

@Xtigyro

• One may choose to use alertmanager as the alerting system for a client other than prometheus.

• One may choose to deploy multiple prometheus releases and a centralized alertmanager release that is not tied to any particular prometheus release

• For systems that deploy a vendored Prometheus but not Alertmanger (namely Linkerd see: https://github.com/linkerd/linkerd2/tree/main/charts/add-ons/prometheus) in which case it would be nice to have a community alertmanager chart to deploy alongside it.

[Xtigyro]

I'm torn here.

@zanhsieh @monotek @bismarck @vsliouniaev @gianrubio
Your thoughts please.

[monotek]

@Xtigyro

Generally i like the idea to have alertmanager as standalone chart, as it can be used as dependency in other charts or you could solve one of the usecases mentioned by @naseemkullah

[Xtigyro]

@naseemkullah Would you be able to work on splitting the Alertmanager component from the prometheus chart and using this as a dependency?

[naseemkullah]

@naseemkullah Would you be able to work on splitting the Alertmanager component from the prometheus chart and using this as a dependency?

Eventually yes, not immediately though, I also think we should discuss the best way forward in terms of feature parity. There is a lot of cruft we should reevaluate in the prometheus chart('s subcomponents). It would not be a bad idea to have a prometheus chart maintainers call at some point to figure out what we want to do.

[Xtigyro]

@naseemkullah Very nice! After resolving the comments from @monotek - I believe this should be good to go.

[monotek]

Maybe it would also make sense to add the same maintainers for the standalone charts as for the prometheus chart?

At least when the standalone chart(s) should be used as dependencies in the prometheus chart later?

Having a call about this sounds good to me too. Not sure if dependency charts should replace current implementation or be usable optionally. So let's have a call :-)

What's your timezone guys? I'm in cet.

[naseemkullah]

Maybe it would also make sense to add the same maintainers for the standalone charts as for the prometheus chart?

At least when the standalone chart(s) should be used as dependencies in the prometheus chart later?

Having a call about this sounds good to me too. Not sure if dependency charts should replace current implementation or be usable optionally. So let's have a call :-)

What's your timezone guys? I'm in cet.

EST, we can start with an async group chat in k8s slack too

@zanhsieh are you on k8s slack?

[scottrigby]

FWIW I'm really encouraged by this thread

[GMartinez-Sisti]

I'm sure you all know this already, but I would like to remind that the Alertmanager deployed in kube-prometheus-stack is managed by the prometheus-operator operator, so I believe this chart does not qualify as a possible dependency for that chart, but instead, as already mentioned, an isolated solution for other use cases.

[naseemkullah]

I'm sure you all know this already, but I would like to remind that the Alertmanager deployed in kube-prometheus-stack is managed by the prometheus-operator operator, so I believe this chart does not qualify as a possible dependency for that chart, but instead, as already mentioned, an isolated solution for other use cases.

Yep this may have gotten buried in the other comments: #64 (comment)

[naseemkullah]

Thanks for the great feedback @monotek , changes applied and ready for re-review.

@zanhsieh @gianrubio @Xtigyro please let me know if you'd like to help maintain this chart as well and I will add you to the maintainers list. Thanks.

[Xtigyro]

@scottrigby Shouldn't we create a PR for the Prometheus chart before merging this one - so no double efforts are required for maintenance of Alertmanager?

[monotek]

@Xtigyro
I don't think so, as this chart is not dependent from the prometheus chart.

Imho we don't plan to change anything in the altermanager component for prometheus so i don't seee double effort there.
It could also be a benefit for others, if they can use it now as they won't need to do work twice.
Standalone usage is also an argument to merge it now.

[scottrigby]

Just this one suggestion. Otherwise this looks good!

[scottrigby]

My only thought now is to improve the README a bit. How about the README template laid out for the other charts in this repo?

[naseemkullah]

Sounds good! I did not find a template per se but mimicked what I saw in prometheus adapter. PTAL

[scottrigby]

Re dependency, we are thinking this could be a drop in replacement for the alert manager in the prometheus chart, right?

If so, I was thinking this is the order:

1. This new alertmanager chart PR must be merged in order to create the chart version package
2. then a PR can be made against the prometheus chart to replace the existing component with this newly available alertmanager package as a dependency

But either way, that would be a follow up PR. Am I right this is what you're thinking though @naseemkullah ?

[Xtigyro]

Re dependency, we are thinking this could be a drop in replacement for the alert manager in the prometheus chart, right?

If so, I was thinking this is the order:

1. This new alertmanager chart PR must be merged in order to create the chart version package

2. then a PR can be made against the prometheus chart to replace the existing component with this newly available alertmanager package as a dependency

But either way, that would be a follow up PR. Am I right this is what you're thinking though @naseemkullah ?

@scottrigby @naseemkullah

OK - very nice! Agreed.
P.S. I'll be happy to help with the follow-up PR.

[scottrigby]

🎉

[torstenwalter]

@naseemkullah @monotek Chart looks great. The only thing which is unclear for me is who maintains that chart?

In CODEOWNERS is says:
/charts/alertmanager/ @monotek @naseemkullah

In Chart.yaml it's just

maintainers:
  - name: naseemkullah
    email: naseem@transit.app