The cluster-wide proxy is getting injected for remote-write config automatically but not the noProxy URLs in Prometheus k8s CR which is available in openshift-monitoring project which is expected. However, if the remote-write endpoint is in noProxy region, then metrics are not transferred.

RHOCP 4.16.4

100%

1. Configure proxy custom resource in RHOCP 4.16.4 cluster
2. Create cluster-monitoring-config configmap in openshift-monitoring project
3. Inject remote-write config (without specifically configuring proxy for remote-write)
4. After saving the modification in  cluster-monitoring-config configmap, check the remoteWrite config in Prometheus k8s CR. Now it contains the proxyUrl but NOT the noProxy URL(referenced from cluster proxy). Example snippet:
==============
apiVersion: monitoring.coreos.com/v1
kind: Prometheus
metadata:
[...]
  name: k8s
  namespace: openshift-monitoring
spec:
[...]
  remoteWrite:
  - proxyUrl: http://proxy.abc.com:8080     <<<<<====== Injected Automatically but there is no noProxy URL.
    url: http://test-remotewrite.test.svc.cluster.local:9090
    

The proxy URL from proxy CR is getting injected in Prometheus k8s CR automatically when configuring remoteWrite but it doesn't have noProxy inherited from cluster proxy resource.

The noProxy URL should get injected in Prometheus k8s CR as well.