[RayService][Observability] Add more loggings about networking issues

[kevin85421]

Why are these changes needed?

Note that NetworkPolicy will not have any effect if you do not have CNI plugin installed in your Kubernetes cluster. Hence, I developed this PR on AWS EKS and installed the CNI plugin Calico.

• Step 1: Follow this doc to install Calico in your EKS cluster.

• Step 2: Create a NetworkPolicy to block all incoming traffic to the Ray head Pod.

   apiVersion: networking.k8s.io/v1
   kind: NetworkPolicy
   metadata:
     name: block-head-pod
   spec:
     podSelector:
       matchLabels:
         ray.io/node-type: head
     ingress: []

• Step 3: Install KubeRay operator with this PR.

  helm install kuberay-operator kuberay/kuberay-operator --version 0.6.1 --set image.repository=$YOUR_DOCKERHUB_REPO,image.tag=$YOUR_DOCKERHUB_TAG

• Step 4: Create a RayService with 1 head Pod and 0 worker Pods. Since incoming traffic is not allowed to reach the Ray head Pod, the init container in the worker Pods will indefinitely wait for GCS to become ready. For this reason, we opt to create 0 worker Pods here.

• Step 5: Check KubeRay operator's log

  kubectl logs $KUBERAY_OPERATOR_POD
  
  # [Example log]
  # 2023-08-01T00:37:37.818Z	ERROR	controllers.RayService	Fail to reconcileServe.	{"ServiceName": "default/rayservice-sample", "error": "Fail to create / update Serve applications. If you observe this error consistently, please check \"Issue 5: Fail to create / update Serve applications.\" in https://github.com/ray-project/kuberay/blob/master/docs/guidance/rayservice-troubleshooting.md for more details.err: Put \"http://rayservice-sample-raycluster-8rshn-head-svc.default.svc.cluster.local:52365/api/serve/applications/\": dial tcp 10.100.192.179:52365: i/o timeout"}
  # sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).Reconcile
  #	/go/pkg/mod/sigs.k8s.io/controller-runtime@v0.11.1/pkg/internal/controller/controller.go:114
  # sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).reconcileHandler
  #	/go/pkg/mod/sigs.k8s.io/controller-runtime@v0.11.1/pkg/internal/controller/controller.go:311
  # sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).processNextWorkItem
  #	/go/pkg/mod/sigs.k8s.io/controller-runtime@v0.11.1/pkg/internal/controller/controller.go:266
  # sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).Start.func2.2
  #	/go/pkg/mod/sigs.k8s.io/controller-runtime@v0.11.1/pkg/internal/controller/controller.go:227

Related issue number

Closes #1279

Checks

• I've made sure the tests are passing.
• Testing Strategy
  • Unit tests
  • Manual tests
  • This PR is not tested :(