Reverse proxy NGINX front-end to redirect Dockerized Apache - apache

Question

I am coming from this. I am new in web-servers. I am setting up a server (example.de) serving several dockerized applications. One of them (app3) is running on behind an Apache server (port 80 inside the container mapped to 8484). I want to use a NGINX docker container to redirect the url example.de/app3 to example.de:8484. Other two applications will be also redirected to example.de/app?.
When I request the url example.de:8484 it works fine. However, when I use example.de/app3 only the "It works" webpage appears.
The docker-compose file is something similar to:
version: '3'
services:
app3:
build:
context: app3
container_name: app3
app3_apache:
build:
context: app3/apache
container_name: app3_apache
ports:
- "8484:80"
volumes:
- vol_app3:/vol/app3
depends_on:
- app3
links:
- app3
nginx-proxy:
container_name: nginx
build:
context: nginx/
ports:
- "80:80"
depends_on:
- app3_apache
links:
- app3_apache
volumes:
- vol_nginx:/etc/nginx/conf.d
volumes:
vol_app3:
driver_opts:
type: none
device: /vol/app3
o: bind
vol_nginx:
driver_opts:
type: none
device: /vol/nginx
o: bind
NGINX default.conf file looks like:
server {
listen 80;
listen [::]:80;
server_name example.de;
location /app3 {
proxy_pass http://app3_apache:80;
}
}
Additional information:
It creates and run the containers. The webpage in the APACHE container is served in the NGINX container using the xxx.xxx.xxx.xxx:80 but not app3_apache:80 <h1>Bad Request (400)</h1>.
I can reach the app3_apache container from the NGINX container:
traceroute app3_apache
traceroute to app3_apache (xxx.xxx.xxx.xxx), 30 hops max, 60 byte packets
1 app3_apache.server_default (xxx.xxx.xxx.xxx) 0.351 ms 0.054 ms 0.035 ms

Answer 1

You should create a docker network to link the container.
You can check docs here: https://docs.docker.com/network/bridge/
After you create the network, you will have to change configuration for nginx proxy_pass to point out the internal IP of the web server application.
As for example I setup this network configuration to connect 3 containers with fixed IP addresses.
version: '2'
services:
zabbix-server4:
container_name: zabbix-server4
image: zabbix/zabbix-server-mysql:alpine-4.0.5
networks:
zbx_net:
aliases:
- zabbix-server4
ipv4_address: 172.16.238.5
zabbix-web4:
container_name: zabbix-web4
image: zabbix/zabbix-web-nginx-mysql:alpine-4.0.5
ports:
- 127.0.0.1:11011:80
links:
- zabbix-server4
environment:
- ZBX_SERVER_HOST=172.16.238.5
networks:
zbx_net:
aliases:
- zabbix-web4
ipv4_address: 172.16.238.10
zabbix-agent4:
container_name: zabbix-agent4
image: zabbix/zabbix-agent:alpine-4.0.5
links:
- zabbix-server4
environment:
- ZBX_SERVER_HOST=172.16.238.5
networks:
zbx_net:
aliases:
- zabbix-agent4
ipv4_address: 172.16.238.15
networks:
zbx_net:
driver: bridge
driver_opts:
com.docker.network.enable_ipv6: "false"
ipam:
driver: default
config:
- subnet: 172.16.238.0/24
gateway: 172.16.238.1
In your case, you could set a new network and assign new network's IPs to both the nginx and web container, then in nginx proxy_pass configuration you should put web server's IP.
E.g:
version: '3'
services:
app3:
build:
context: app3
container_name: app3
app3_apache:
build:
context: app3/apache
container_name: app3_apache
ports:
- "8484:80"
volumes:
- vol_app3:/vol/app3
depends_on:
- app3
links:
- app3
networks:
my_net:
aliases:
- zabbix-agent4
ipv4_address: 172.16.11.10
nginx-proxy:
container_name: nginx
build:
context: nginx/
ports:
- "80:80"
depends_on:
- app3_apache
links:
- app3_apache
volumes:
- vol_nginx:/etc/nginx/conf.d
networks:
my_net:
aliases:
- zabbix-agent4
ipv4_address: 172.16.11.20
volumes:
vol_app3:
driver_opts:
type: none
device: /vol/app3
o: bind
vol_nginx:
driver_opts:
type: none
device: /vol/nginx
o: bind
networks:
my_net:
driver: bridge
driver_opts:
com.docker.network.enable_ipv6: "false"
ipam:
driver: default
config:
- subnet: 172.16.11.0/24
gateway: 172.16.11.1
And proxy pass should be sety to
location /app3 {
proxy_pass http://172.16.11.10:80;
}
To prevent having this trouble, I run nginx on host, not in a container, then I split traffic in containers using same approach.
Having nginx installed in the host machine allow me to avoid this kind of configuration overhead.