nginx-proxy for more than one node app docker

Question

i am trying nginx reverse proxy multiple container .

i have 2 container which have node add one listen on 8085 and other on 8086 i want them to access by

node.app1.com

node.app2.com

so i used jwilder/nginx-proxy:latest which will sit in fount of both of these container and will act as revers proxy . so here is my compose.yml file.

---

docker-compose.yml

version: "3"
services:
  node-proxy:
    build:  ./node-proxy
    container_name : node-proxy
    restart : always
    volumes:  
        -  /var/run/docker.sock:/tmp/docker.sock:ro
    ports:
      - 80:80
      - 443:443
  node-app1:
    build:  ./app1
    container_name : node-app1
    restart: always
    environment:
      VIRTUAL_HOST: node.app1.com
    depends_on:
      - node-proxy
  node-app2:
    build:  ./app2
    container_name : node-app2
    restart: always
    environment:
      VIRTUAL_HOST: node.app2.com
    depends_on:
      - node-proxy

./node-proxy/Dockerfile

FROM jwilder/nginx-proxy:latest

./app1/app1.js

var http = require("http");

http.createServer(function (request, response) {

   response.writeHead(200, {'Content-Type': 'text/plain'});
   response.end('Hello World 1\n');
}).listen(8085);

./app1/Dockerfile

FROM node:6.11
WORKDIR /app2
COPY app1.js .
CMD node app1.js
Expose 8085

./app2/app2.js

var http = require("http");

http.createServer(function (request, response) {

   response.writeHead(200, {'Content-Type': 'text/plain'});
   response.end('Hello World 2\n');
}).listen(8086);

./app2/Dockerfile

FROM node:6.11
WORKDIR /app2
COPY app2.js .
CMD node app2.js
Expose 8086

So when i do

docker-compose up 

all my containers are up and running

but when do node.app1.com --> it say's unknown host .

so to check wether request is coming to proxy i tryed calling http://localhost from browser and it says 503

i also checked nginx.config in side container by

docker exec -it node-proxy_id bash

cat /etc/nginx/conf.d/

and its there but i think when i do node.app1.com request not coming to proxy . i am not getting where i have missed , can some one help me out with this .

Thanks for your time

Answer 1

When you set links or depends_on to the other services, docker-compose will set up other services host name as its container_name in same docker network by default.

In your case, I would suggest to add links as @Mathias respond for.

version: "3"
services:
  node-app1:
    build:  ./app1
    container_name : node-app1
    restart: always
    expose:
      - "8085"
    environment:
      VIRTUAL_HOST: node.app1.com
  node-app2:
    build:  ./app2
    container_name : node-app2
    restart: always
    expose:
      - "8086"
    environment:
      VIRTUAL_HOST: node.app2.com
  node-proxy:
    build:  ./node-proxy
    container_name : node-proxy
    restart : always
    links:
        - node-app1
        - node-app2
    volumes:
        -  /var/run/docker.sock:/tmp/docker.sock:ro
    ports:
        - 80:80
        - 443:443

Updated:

I noticed that Nginx config have upstream directive to hold multiple host names. You should be able to curl the node-app1 as:

$ curl -H 'Host: node.app1.com' localhost
Hello World 1

You can also modify last line in etc/hosts file in your node-proxy container as:

172.20.0.4 [docker-network-alias] node.app1.com node.app2.com

Then you should be able to visit http://node.app1.com directly inside your node-proxy container.

Here's a tutorial to set up nginx virtual hosts on ubuntu 16 04

Comment I:

In my understanding, the nginx-proxy is tend to proxy request to back-end service which does not have to register a hostname in /etc/hosts file. So we fire a request with Host header which is a virtual hostname in Nginx upstream block.

The nginx-proxy have done this part for you when you create the environment variable VIRTUAL_HOST in each app container setting. But it does not mean we can directly visit the node.app1.com in our browser and expect the request will be proxied and respond by node-app1 container.

Back to request forwarding part, the request come to localhost at port 80/443 which is listened by Nginx. Nginx then check the Host header to go into specific location block. That is why you cannot directly visit http://node.app1.com in your browser, because that hostname is never be really registered in etc/hosts, so it will never be addressed by any server, app, or our nginx-proxy.

If we want to visit thay hostname by browser, the extra setting for etc/hosts is needed.

The nginx-proxy project supply some template setting, so you might able to get the IP of app containers and its VIRTUAL_HOST environment then append it to /etc/hosts file. But in such way this would be directly visit to node app server instead of proxy from nginx-proxy.

Without production level concern, I would suggest to append app domains in etc/hosts file at last line which is set by nginx-proxy, then it should work as you expected. Otherwise the work for hostname dynamic binding from nginx-proxy templates is necessary.

Answer 2

Look at the ports of your app / Dockerfile:

./app1/app1.js

}).listen(8085);

and

./app1/Dockerfile

Expose 8086

they are missmatching.

---

The part i was missing is that jwilder/nginx-proxy is reflecting docker to look for containers that needs to be proxied.

Original post:

I guess that your problem is that reverse proxy container cannot reach each app. Therefor remove the depends_on from node-app1 and node-app2 and add in node-proxy:

links:
 - node-app1
 - node-app2 

The reverse proxy requires both apps to be started and not the other way around. Also use links instead of depends_on.

From the docs:

depends_on

Express dependency between services, which has two effects:

• docker-compose up will start services in dependency order. In the following example, db and redis will be started before web.

• docker-compose up SERVICE will automatically include SERVICE’s dependencies. In the following example, docker-compose up web will also create and start db and redis.

links

Containers for the linked service will be reachable at a hostname identical to the alias, or the service name if no alias was specified.

Links also express dependency between services in the same way as depends_on, so they determine the order of service startup.

I'm also not sure how you get to the IP addresses of this containers in your proxy config. You can use (as it says in the documentation) the alias or service name instead. (in your case node-app1 and node-app2)