NGINX container as a proxy for other containers - docker

Question

I am trying to run of containers on my UBUNTU server, these containers are:
DNS servers with bind9.
NTP server with cturra/ntp.
NGINX for reverse proxy => reverse proxy for DNS and NTP
I have these containers in the same yaml file:
version: '3'
services:
reverse-proxy-engine:
image: nginx
container_name: reverse-proxy-engine
volumes:
- ~/core/reverse-proxy/:/usr/share/nginx/
ports:
- "80:80"
- "443:443"
- "53:53"
- "123:123/udp"
depends_on:
- "DNS-SRV"
- "ntp"
DNS-SRV:
container_name: DNS-SRV
image: ubuntu/bind9
user: root
environment:
- TZ=UTC
volumes:
- ~/core/bind9/:/etc/bind/
ntp:
image: cturra/ntp
container_name: ntp
restart: always
read_only: true
tmpfs:
- /etc/chrony:rw,mode=1750
- /run/chrony:rw,mode=1750
- /var/lib/chrony:rw,mode=1750
environment:
- NTP_SERVERS=time.cloudflare.com
- LOG_LEVEL=0
After running this yaml file, the containers are created and I see the ports mapped correctly:
admin#main-srv:~/core/yamls$ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
4720bae2a44c nginx "/docker-entrypoint.…" 5 seconds ago Up 4 seconds 0.0.0.0:53->53/tcp, 0.0.0.0:80->80/tcp, 0.0.0.0:443->443/tcp, 0.0.0.0:123->123/udp reverse-proxy-engine
1681814f651e cturra/ntp "/bin/sh /opt/startu…" 6 seconds ago Up 5 seconds (health: starting) 123/udp ntp
dde2f9094b45 ubuntu/bind9 "docker-entrypoint.sh" 6 seconds ago Up 5 seconds 53/tcp DNS-SRV
I am able to access the nginx webpage on the browser using port 80 with <UBUNTU_SERVER_IP:80>, but I'm unable to use this same IP to resolve DNS or NTP on the same network, but within the containers network, it's working.
So I think that NGINX ports are exposed to the UBUNTU server, but the DNS and NTP ports are not exposed to NGINX, would that be correct? What am I missing?
Below is my NginX configuration file:
events {
worker_connections 1024;
}
stream {
upstream dns_servers {
server DNS-SRV:53;
}
upstream ntp_server {
server ntp:123;
}
server {
listen 53 udp;
listen 53; #tcp
proxy_pass dns_servers;
error_log /var/log/nginx/dns.log info;
proxy_responses 1;
proxy_timeout 1s;
}
server {
listen 123 udp;
listen 123; #tcp
proxy_pass ntp_server;
error_log /var/log/nginx/ntp.log info;
proxy_responses 1;
proxy_timeout 1s;
}
}
So far it seems logical to me, any ideas?

Answer 1

I think that's because you don't set hostname for bind and ntp container, I use below configuration and get it working
version: '3'
services:
reverse-proxy-engine:
image: nginx
container_name: reverse-proxy-engine
volumes:
- ~/core/reverse-proxy/:/usr/share/nginx/
- $PWD/nginx.conf:/etc/nginx/nginx.conf
ports:
- "80:80"
- "443:443"
- "53:53"
- "123:123/udp"
depends_on:
- "DNS-SRV"
- "ntp"
DNS-SRV:
container_name: DNS-SRV
hostname: DNS-SRV
image: ubuntu/bind9
user: root
environment:
- TZ=UTC
volumes:
- ~/core/bind9/:/etc/bind/
ntp:
image: cturra/ntp
container_name: ntp
hostname: ntp
restart: always
read_only: true
tmpfs:
- /etc/chrony:rw,mode=1750
- /run/chrony:rw,mode=1750
- /var/lib/chrony:rw,mode=1750
environment:
- NTP_SERVERS=time.cloudflare.com
- LOG_LEVEL=0
In above configuration I add hostname for bind and ntp container, also i mount nginx configuration and replace the default configuration.
Below nginx.conf configuration
user nginx;
worker_processes auto;
error_log /var/log/nginx/error.log notice;
pid /var/run/nginx.pid;
events {
worker_connections 1024;
}
http {
include /etc/nginx/mime.types;
default_type application/octet-stream;
log_format main '$remote_addr - $remote_user [$time_local] "$request" '
'$status $body_bytes_sent "$http_referer" '
'"$http_user_agent" "$http_x_forwarded_for"';
access_log /var/log/nginx/access.log main;
sendfile on;
#tcp_nopush on;
keepalive_timeout 65;
#gzip on;
include /etc/nginx/conf.d/*.conf;
}
stream {
upstream dns_servers {
server DNS-SRV:53;
}
upstream ntp_server {
server ntp:123;
}
server {
listen 53 udp;
listen 53; #tcp
proxy_pass dns_servers;
error_log /var/log/nginx/dns.log info;
proxy_responses 1;
proxy_timeout 1s;
}
server {
listen 123 udp;
listen 123; #tcp
proxy_pass ntp_server;
error_log /var/log/nginx/ntp.log info;
proxy_responses 1;
proxy_timeout 1s;
}
}
Note: Make sure the binding port you use 80, 443, 53, 123 not used by other application.