spring boot on azure Internal Server Error - docker

Question

I have a very simple "Hello" spring-boot application
#RestController
public class HelloWorld {
#RequestMapping("/")
public String sayHello() {
return "Hello Spring Boot!!";
}
}
I packaged Dockerfile
FROM java:8
COPY ./springsimple-1.0-SNAPSHOT.jar /Users/a/Documents/dev/intellij/dockerImages/
WORKDIR /Users/a/Documents/dev/intellij/dockerImages/
EXPOSE 8090
CMD ["java", "-jar", "springsimple-1.0-SNAPSHOT.jar"]
and pulled into my container registry and deployed it
amhg$ kubectl run testproject --image acontainerregistry.azurecr.io/hellospring:v1
deployment.apps "testproject" created
amhg$ kubectl expose deployments testproject --port=5000 --type=LoadBalancer
service "testproject" exposed
command kubectl get pods
NAME READY STATUS RESTARTS AGE
testproject-bdf5b54d-gkk92 1/1 Running 0 41s
However when I try the command (Starting to serve on 127.0.0.1:8001) I got the error:
amhg$ curl http://127.0.0.1:8001/api/v1/proxy/namespaces/default/pods/testproject-bdf5b54d-gkk92/
Internal Server Error
What is missing?
The description of the pod is
amhg$ kubectl describe pod testproject-bdf5b54d-gkk92
Name: testproject-bdf5b54d-gkk92
Namespace: default
Node: aks-nodepool1-39744669-0/10.240.0.4
Start Time: Thu, 19 Apr 2018 13:13:20 +0200
Labels: pod-template-hash=68916108
run=testproject
Annotations: kubernetes.io/created-by={"kind":"SerializedReference","apiVersion":"v1","reference":{"kind":"ReplicaSet","namespace":"default","name":"testproject-bdf5b54d","uid":"aa99808e-43c2-11e8-9537-0a58ac1f0f4...
Status: Running
IP: 10.244.0.40
Controlled By: ReplicaSet/testproject-bdf5b54d
Containers:
testproject:
Container ID: docker://6ed3878fa4476a5d2e56f0ba70908742702709c7505c7b19989efc6ff658ea55
Image: acontainerregistry.azurecr.io/hellospring:v1
Image ID: docker-pullable://acontainerregistry.azurecr.io/azure-vote-front#sha256:e2af252d275c99b802e21b3b469c75b256d7812ee71d7582cd759bd4faf5a6ec
Port: <none>
Host Port: <none>
State: Running
Started: Thu, 19 Apr 2018 13:13:21 +0200
Ready: True
Restart Count: 0
Environment: <none>
Mounts:
/var/run/secrets/kubernetes.io/serviceaccount from default-token-vkpjm (ro)
Conditions:
Type Status
Initialized True
Ready True
PodScheduled True
Volumes:
default-token-vkpjm:
Type: Secret (a volume populated by a Secret)
SecretName: default-token-vkpjm
Optional: false
QoS Class: BestEffort
Node-Selectors: <none>
Tolerations: node.alpha.kubernetes.io/notReady:NoExecute for 300s
node.alpha.kubernetes.io/unreachable:NoExecute for 300s
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Scheduled 57m default-scheduler Successfully assigned testproject-bdf5b54d-gkk92 to aks-nodepool1-39744669-0
Normal SuccessfulMountVolume 57m kubelet, aks-nodepool1-39744669-0 MountVolume.SetUp succeeded for volume "default-token-vkpjm"
Normal Pulled 57m kubelet, aks-nodepool1-39744669-0 Container image "acontainerregistry.azurecr.io/hellospring:v1" already present on machine
Normal Created 57m kubelet, aks-nodepool1-39744669-0 Created container
Normal Started 57m kubelet, aks-nodepool1-39744669-0 Started container

Answer 1

Let's start from the beginning: it is always better to use YAML config files to do anything with Kubernetes. It will help you with debugging if something goes wrong and repeat your action in future.
First, you use the command to create the pod:
kubectl run testproject --image acontainerregistry.azurecr.io/hellospring:v1
where YAML looks like:
apiVersion: v1
kind: Pod
metadata:
name: test-app
spec:
containers:
- name: java-app
image: acontainerregistry.azurecr.io/hellospring:v1
ports:
- containerPort: 8090
and you can apply it as a command:
kubectl apply -f ./pod.yaml
You get the same result as while running your command, but additionally you have the config file which can be used in future.
You`re trying to expose your pod using command:
kubectl expose deployments testproject --port=5000 --type=LoadBalancer
YAML for your service looks like:
apiVersion: v1
kind: Service
metadata:
name: java-service
labels:
name: test-app
spec:
type: LoadBalancer
ports:
- port: 5000
targetPort: 8090
name: http
selector:
name: test-app
Doing the same but with using YAML allows to describe more and be sure you don't miss anything.
You tried to curl the localhost but I`m not sure what did you expect from this command:
amhg$ curl http://127.0.0.1:8001/api/v1/proxy/namespaces/default/pods/testproject-bdf5b54d-gkk92/
Internal Server Error
After you create the service, you call kubectl describe service $service_name, which you can find here:
LoadBalancer Ingress: XX.XX.XX.XX
Port: http 5000/TCP
You can curl this address and receive the answer from your application.
curl -v XX.XX.XX.XX:5000
Don't forget to open the port on Azure firewall.