Internal DNS w/ Headless - Cant ping stateful pods

Rancher
1

Hi Everyone,

I have been trying to ping replica X from replica Y in a statefulset without luck. Tried the suggested fixes of making sure the service and workload labels are the same (checks out), checking the pod resolv.conf (checks out), pinging kubernetes from within pod (checks out). Pinging service-1 from service-0 does not work using pod name or FQDN.

I’m using the K8s sample as a ‘this should work’ – and it doesn’t.

Given the headless service and nginx workload below, I should be able to,

kubectl exec -it web-0 -- ping web-1

and have it work … but no love.

Any suggestions?

kubectl version

Client Version: version.Info{Major:“1”, Minor:“14”, GitVersion:“v1.14.0”, GitCommit:“641856db18352033a0d96dbc99153fa3b27298e5”, GitTreeState:“clean”, BuildDate:“2019-03-25T15:53:57Z”, GoVersion:“go1.12.1”, Compiler:“gc”, Platform:“darwin/amd64”}

Server Version: version.Info{Major:“1”, Minor:“13”, GitVersion:“v1.13.5”, GitCommit:“2166946f41b36dea2c4626f90a77706f426cdea2”, GitTreeState:“clean”, BuildDate:“2019-03-25T15:19:22Z”, GoVersion:“go1.11.5”, Compiler:“gc”, Platform:“linux/amd64”}

Rancher Version : 2.2.4
K8s Version : 1.13.5-rancher1-2
Network : Canal (project network isolation : disabled)

apiVersion: v1
kind: Service
metadata:
  name: nginx
  labels:
    app: nginx
spec:
  ports:
  - port: 80
    name: web
  clusterIP: None
  selector:
    app: nginx
---
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: web
spec:
  selector:
    matchLabels:
      app: nginx # has to match .spec.template.metadata.labels
  serviceName: "nginx"
  replicas: 3 # by default is 1
  template:
    metadata:
      labels:
        app: nginx # has to match .spec.selector.matchLabels
    spec:
      terminationGracePeriodSeconds: 10
      containers:
      - name: nginx
        image: k8s.gcr.io/nginx-slim:0.8
        ports:
        - containerPort: 80
          name: web
        volumeMounts:
        - name: www
          mountPath: /usr/share/nginx/html
  volumeClaimTemplates:
  - metadata:
      name: www
    spec:
      accessModes: [ "ReadWriteOnce" ]
      storageClassName: "my-storage-class"
      resources:
        requests:
          storage: 1Gi