Add support for enable_http2 in service monitor, pod monitor and probe

[igorgosh-sap]

What did you do?
We're trying to upgrade kube-prometheus-stack to version 2.35
We used to build prometheus image with ENV PROMETHEUS_COMMON_DISABLE_HTTP2=1 in previous versions to turn off http2
but it's no longer working. In version 2.35 new parameter was introduced enable_http2 and it's set to true by default

Did you expect to see some different?
We're unable to set enable_http2 to false for service monitors globally or override existing jobs.
It looks like prometheus operator doesn't handle enable_http2 correctly?

Environment

• Prometheus Operator version:

  v0.56.2

• Kubernetes version information:

  Client Version: version.Info{Major:"1", Minor:"21", GitVersion:"v1.21.9", GitCommit:"b631974d68ac5045e076c86a5c66fba6f128dc72", GitTreeState:"clean", BuildDate:"2022-01-19T17:51:12Z", GoVersion:"go1.16.12", Compiler:"gc", Platform:"darwin/amd64"} Server Version: version.Info{Major:"1", Minor:"21", GitVersion:"v1.21.9", GitCommit:"b631974d68ac5045e076c86a5c66fba6f128dc72", GitTreeState:"clean", BuildDate:"2022-01-19T17:45:53Z", GoVersion:"go1.16.12", Compiler:"gc", Platform:"linux/amd64"}

• Kubernetes cluster kind:

  insert how you created your cluster: kops, bootkube, etc.

• Manifests:

insert manifests relevant to the issue

• Prometheus Operator Logs:

insert Prometheus Operator logs relevant to the issue here

Anything else we need to know?:

[mikechengwei]

/assign

[martin2110]

I ran in to this also, remote_write needs it also.

[johgoe]

This should be the flag: enable_http2 for the scrape configuration https://github.com/prometheus/prometheus/blob/main/docs/configuration/configuration.md

see: prometheus/prometheus#10492

[simonpasquier]

The solution would be to extend ServiceMonitor, PodMonitor and Probe CRDs with a new enableHTTP2 field. For instance:

apiVersion: monitoring.coreos.com/v1
kind: ServiceMonitor
metadata:
  name: example-app
spec:
  selector:
    matchLabels:
      app: example-app
  endpoints:
  - port: web
    enableHTTP2: true

[QuentinBisson]

@simonpasquier this is still an issue for remote write. Should I open another issue ?

[simonpasquier]

@QuentinBisson yes please!