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k8s ambassador ingress sample not working

12/3/2019

I'm currently on OSX (Catalina) with Docker Desktop (19.03.5) running k8s (v.14.8)

Following the ambassador getting started article, I've done the following:

Created a file called ambassador-ingress.yaml

---
apiVersion: v1
kind: Service
metadata:
  labels:
    service: ambassador
  name: ambassador
spec:
  type: LoadBalancer
  ports:
  - port: 80
    targetPort: 80
  selector:
    service: ambassador
---
apiVersion: v1
kind: Service
metadata:
  name: google
  annotations:
    getambassador.io/config: |
      ---
      apiVersion: ambassador/v0
      kind:  Mapping
      name:  google_mapping
      prefix: /google/
      service: https://google.com:443
      host_rewrite: www.google.com
spec:
  type: ClusterIP
  clusterIP: None

And I've run the following

$ kubectl apply -f https://www.getambassador.io/yaml/ambassador/ambassador-rbac.yaml
$ kubectl apply -f ambassador-ingress.yaml

I can now look at kubectl get pods and kubectl get service

$ kubectl get pods
NAME                                         READY   STATUS    RESTARTS   AGE
ambassador-74fb8f5668-2b85z                  1/1     Running   0          20m
ambassador-74fb8f5668-r6jrf                  1/1     Running   0          20m
ambassador-74fb8f5668-vrmjg                  1/1     Running   0          20m

$ kubectl get service
NAME                 TYPE           CLUSTER-IP       EXTERNAL-IP   PORT(S)          AGE
ambassador           LoadBalancer   10.97.166.229    localhost     80:31327/TCP     18m
ambassador-admin     NodePort       10.96.1.56       <none>        8877:30080/TCP   18m
google               ClusterIP      None             <none>        <none>           18m
kubernetes           ClusterIP      10.96.0.1        <none>        443/TCP          13d

Everything looks like it is setup correctly, however, whenever I attempt to curl k8s I can't get anything but an empty server response even though I can hit google directly:

$ curl localhost/google/
> curl: (52) Empty reply from server
$ curl www.google.com
> <!doctype html> ............

The question I have is, where do I begin troubleshooting? I don't know where the failure lies or how to begin digging to find what has gone wrong. What is the right direction?

-- Paul Nelson Baker

kubernetes

1 Answer

12/3/2019

Based on "The Kubernetes network model" [1] there are 2 important rules:

pods on a node can communicate with all pods on all nodes without NAT
agents on a node (e.g. system daemons, kubelet) can communicate with all pods on that node

So basically it says that since your K8s cluster is located on your machine, you can directly communicate to the service ip "10.97.166.229" and POD IP.

So, regarding how to begin your troubleshooting steps, since your PODs are up and running, most likely this is a network error. You can try this:

a) Try to connect to your pod directly. You can get your IP by executing the command:

kubectl get pod -o wide

b) Get the LOGs of your POD and search for any error:

kubectl logs ambassador-74fb8f5668-2b85z

c) Go inside your POD and check if you can test connectivity inside your POD. [2]

kubectl exec -it ambassador-74fb8f5668-2b85z -- /bin/bash

[1] https://kubernetes.io/docs/concepts/cluster-administration/networking/

[2] https://kubernetes.io/docs/tasks/debug-application-cluster/get-shell-running-container/

-- Armando Cuevas

Source: StackOverflow

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k8s ambassador ingress sample not working

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