Tag: docker

I have the following docker-compose file that works finely:

version: '3'
services:
myfrontend: 
  image: myregistry.azurecr.io/im1:latest
  container_name: myfrontend
   ports:
  - 80:80
  - 443:443

 mybackend:
image: myregistry.azurecr.io/im2:latest
container_name: mybackend
expose: 
  - 8080

The backend only exposes 8080 to the internal network, the frontend has a modded nginx image with the following configuration (and it works as docker resolves the ip with the container name)

server {
listen 80 default_server;
location / {
    auth_basic "Restricted";
    auth_basic_user_file /etc/nginx/.htpasswd;

    resolver 127.0.0.11 ipv6=off;

    set $springboot "http://mybackend:8080";
    proxy_pass $springboot;
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header Host $host;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
}

I migrated the above configuration into kubernates and I get a 502 bad gateway error from nginx, I think because it cannot solve the backend address.

Here’s the kubernates conf, can you give it a look and tell me what am I doing wrong? 😦

apiVersion: apps/v1beta1
kind: Deployment
metadata:
 name: mybackend
spec:
 replicas: 1
 strategy:
   rollingUpdate:
    maxSurge: 1
    maxUnavailable: 1
  minReadySeconds: 5
 template:
   metadata:
  labels:
    app: mybackend
spec:
  nodeSelector:
    "beta.kubernetes.io/os": linux
  containers:
  - name: mybackend
    image: myregistry.azurecr.io/sgr-mybackend:latest
    ports:
    - containerPort: 8080
      name: mybackend
    resources:
      requests:
        cpu: 250m
        limits:
          cpu: 500m
---
apiVersion: v1
kind: Service
metadata:
  name: mybackend
spec:
  ports:
  - port: 8080
  selector:
    app: mybackend
 ---
 apiVersion: apps/v1beta1
 kind: Deployment
 metadata:
 name: myfrontend
 spec:
   replicas: 1 
 template:
 metadata:
  labels:
    app: myfrontend
 spec:
  nodeSelector:
    "beta.kubernetes.io/os": linux
  containers:
  - name: myfrontend
    image: myregistry.azurecr.io/myfrontend:latest
    ports:
    - containerPort: 80
---
apiVersion: v1
kind: Service
metadata:
  name: myfrontend
spec:
  type: LoadBalancer
  ports:
  - port: 80
  selector:
    app: myfrontend

Solution:

you need to set your resolver to this:

kube-dns.kube-system.svc.cluster.local

so the kube-dns name\address in your cluster, because nothing on localhost would resolve mybackend to its ip address. I’m not sure you need this at all, because container would know backend address from kubernetes anyway. I’d probably drop that setting