Docker - Access nginx container using nginx server_name from another container - docker

Question

I have one node.js application (web-app) and two lumen applications (api, customer-api) that are load balanced by an nginx container listening on port 80.
My docker-compose.yml file:
version: '2'
services:
nginx:
build:
context: ../
dockerfile: posbytz-docker/nginx/dockerfile
volumes:
- api
- customer-api
ports:
- "80:80"
networks:
- network
depends_on:
- web-app
- api
- customer-api
web-app:
build:
context: ../
dockerfile: posbytz-docker/web-app-dockerfile
volumes:
- ../web-app:/posbytz/web-app
- /posbytz/web-app/node_modules
ports:
- "3004:3004"
networks:
- network
api:
build:
context: ../
dockerfile: posbytz-docker/api-dockerfile
volumes:
- ../api:/var/www/api
networks:
- network
customer-api:
build:
context: ../
dockerfile: posbytz-docker/customer-api-dockerfile
volumes:
- ../customer-api:/var/www/customer-api
networks:
- network
redis:
image: redis
ports:
- "6379:6379"
networks:
- network
memcached:
image: memcached
ports:
- "11211:11211"
networks:
- network
mysql:
image: mysql:5.7
volumes:
- ./db-data:/var/lib/mysql
ports:
- "3306:3306"
networks:
- network
adminer:
image: adminer
restart: always
ports:
- "9001:8080"
networks:
- network
networks:
network:
driver: bridge
Since I am using a bridged network, I am able to access each container from another container using the container names. But what I want instead is, access the containers using the server_name of their nginx configuation.
Below are the nginx configuration of each application,
web-app.conf:
server {
listen 80;
server_name posbytz.local;
resolver 127.0.0.11 valid=10s;
location / {
proxy_pass http://web-app:3004;
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection 'upgrade';
proxy_set_header Host $host;
proxy_cache_bypass $http_upgrade;
}
}
api.conf:
server {
listen 80;
index index.php index.html;
root /var/www/api/public;
server_name api.posbytz.local;
resolver 127.0.0.11 valid=10s;
location / {
try_files $uri /index.php?$args;
}
location ~ \.php$ {
fastcgi_split_path_info ^(.+\.php)(/.+)$;
fastcgi_pass api:9000;
fastcgi_index index.php;
include fastcgi_params;
fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
fastcgi_param PATH_INFO $fastcgi_path_info;
}
}
customer-api.conf
server {
listen 80;
index index.php index.html;
root /var/www/customer-api/public;
server_name customer-api.posbytz.local;
resolver 127.0.0.11 valid=10s;
location / {
try_files $uri /index.php?$args;
}
location ~ \.php$ {
fastcgi_split_path_info ^(.+\.php)(/.+)$;
fastcgi_pass customer-api:9000;
fastcgi_index index.php;
include fastcgi_params;
fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
fastcgi_param PATH_INFO $fastcgi_path_info;
}
}
The problem
I want to access both api and customer-api containers from web-app container. The problem is when I try curl http://nginx I'am only getting response from the api container. Is there any way to access the customer-api container through the nginx container?
What I tried
When I manually mapped the IP of nginx container (172.21.0.9) with their respective server_name in the /etc/hosts file on the web-app container it seems to work.
What I added on /etc/hosts file on web-app container:
172.21.0.9 api.posbytz.local
172.21.0.9 customer-api.posbytz.local
Is there any other way to achieve this without manual intervention?

Answer 1

Finally made it to work by changing the nginx configuration on customer-api.conf to listen on port 81 ie. listen 80; to listen 81;. Now http://nginx resolves to http://api:9000 and http://nginx:81 resolves to http://customer-api:9000

Answer 2

You can use aliases:
networks:
some-network:
aliases:
- api.posbytz.local
- customer-api.posbytz.local