Kubernetes - Ingress / Service / LB - node.js

Question

I am new to K8s and this is my first time trying to get to grips with it. I am trying to set up a basic Nodejs Express API using this deployment.yml:
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
name: api
spec:
replicas: 1
template:
metadata:
labels:
app: api
spec:
containers:
- image: registry.gitlab.com/<project>/<app>:<TAG>
imagePullPolicy: Always
name: api
env:
- name: PORT
value: "8080"
ports:
- containerPort: 8080
hostPort: 80
livenessProbe:
httpGet:
path: /healthz
port: 8080
initialDelaySeconds: 30
timeoutSeconds: 1
readinessProbe:
httpGet:
path: /healthz
port: 8080
initialDelaySeconds: 30
timeoutSeconds: 1
imagePullSecrets:
- name: registry.gitlab.com
Which is being deployed via gitlab-ci. This is working and I have set up a service to expose it:
apiVersion: v1
kind: Service
metadata:
name: api-svc
labels:
app: api-svc
spec:
ports:
- port: 80
targetPort: 80
protocol: TCP
name: http
selector:
app: api
type: LoadBalancer
But I have been looking into ingress to have a single point of entry for possibly multiple services. I have been reading through Kubernetes guides and I read through this Kubernetes Ingress Example and this is the ingress.yml I created:
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: ingress
spec:
backend:
serviceName: api-svc
servicePort: 80
But this did not work, when I visited the external IP address that was generated from the ingress and I just 502 error pages.
Could anyone point me in the right direction, what am I doing wrong or what am I missing? I see that in the example link above that there is an nginx-rc.yml which I deployed exactly like in the example and that was created but still got nothing from the endpoint. The API was accessible from the Service external IP though..
Many Thanks

Answer 1

I have looked into it again and think I figured it out.
In order for Ingress to work on GCE you need to define your backend service das a NodePort not as ClusterIP or LoadBalancer.
Also you need to make sure the http health check to / works (you'll see the Google L7 Loadbalancer hitting your service quite a lot on that url) and then it's available.

Answer 2

Thought I would post my working deployment/service/ingress
So after much effort in getting this working, here is what I used to get it working:
Deployment
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
name: backend-api-v2
spec:
replicas: 2
template:
metadata:
labels:
app: backend-api-v2
spec:
containers:
- image: registry.gitlab.com/<project>/<app>:<TAG>
imagePullPolicy: Always
name: backend-api-v2
env:
- name: PORT
value: "8080"
ports:
- containerPort: 8080
livenessProbe:
httpGet:
# Path to probe; should be cheap, but representative of typical behavior
path: /healthz
port: 8080
initialDelaySeconds: 30
timeoutSeconds: 5
readinessProbe:
httpGet:
path: /healthz
port: 8080
initialDelaySeconds: 30
timeoutSeconds: 5
imagePullSecrets:
- name: registry.gitlab.com
Service
apiVersion: v1
kind: Service
metadata:
name: api-svc-v2
labels:
app: api-svc-v2
spec:
type: NodePort
ports:
- port: 80
targetPort: 8080
nodePort: 31810
protocol: TCP
name: http
selector:
app: backend-api-v2
Ingress
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: app-ingress
spec:
rules:
- host: api.foo.com
http:
paths:
- path: /v1/*
backend:
serviceName: api-svc
servicePort: 80
- path: /v2/*
backend:
serviceName: api-svc-v2
servicePort: 80
The important bits to notice as #Tigraine pointed out is the service is using type: NodePort and not LoadBalancer, I have also defined a nodePort but I believe it will create one if you leave it out.
It will use the default-http-backend for any routes that don't match the rules this is a default container that GKE runs in the kube-system namespace. So if I visited http://api.foo.com/bob I get the default response of default backend - 404.
Hope this helps

Answer 3

Looks like you're exposing your service to port 80 but your container is exposing 8080 so any request to the service is going to fail.
Also, have a look at the sample ingress resource (https://github.com/nginxinc/kubernetes-ingress/blob/master/examples/complete-example/cafe-ingress.yaml), you need to also define which hosts / paths route when the ingress controller is hit. (i.e. example.foo.com --> api-svc)