Nginx Reverse Proxy on Docker - How to connect to other application? - docker

Question

I have Joplin running in a docker container on my NAS using docker compose. Now I want to setup a reverse proxy in order to make it accessible via my personal domain.
The joplin/docker-compose.yml file looks as follows:
version: '3'
services:
db:
image: postgres:13.1
volumes:
- /local/joplin:/var/lib/postgresql/data
restart: unless-stopped
environment:
- APP_PORT=22300
- POSTGRES_PASSWORD=********
- POSTGRES_USER=user
- POSTGRES_DB=database
app:
image: joplin/server:2.2.10
depends_on:
- db
ports:
- "22300:22300"
restart: unless-stopped
environment:
- APP_PORT=22300
- APP_BASE_URL=http://192.168.1.2:22300/
- DB_CLIENT=pg
- POSTGRES_PASSWORD=********
- POSTGRES_DATABASE=database
- POSTGRES_USER=user
- POSTGRES_PORT=5432
- POSTGRES_HOST=db
The nginx/docker-compose.yml file looks like this:
version: '3'
services:
nginx:
image: nginx:latest
ports:
- 8080:80
volumes:
- /local/nginx/nginx.conf:/etc/nginx/nginx.conf
- /local/nginx/sites-enabled:/etc/nginx/sites-enabled
I used the default for my /local/nginx/nginx.conf. It is as follows. :
user www-data;
worker_processes auto;
pid /run/nginx.pid;
include /etc/nginx/modules-enabled/*.conf;
events {
worker_connections 768;
}
http {
##
# Basic Settings
##
sendfile on;
tcp_nopush on;
tcp_nodelay on;
keepalive_timeout 65;
types_hash_max_size 2048;
include /etc/nginx/mime.types;
default_type application/octet-stream;
##
# SSL Settings
##
ssl_protocols TLSv1 TLSv1.1 TLSv1.2 TLSv1.3; # Dropping SSLv3, ref: POODLE
ssl_prefer_server_ciphers on;
##
# Logging Settings
##
access_log /var/log/nginx/access.log;
error_log /var/log/nginx/error.log;
##
# Gzip Settings
##
gzip on;
##
# Virtual Host Configs
##
include /etc/nginx/conf.d/*.conf;
include /etc/nginx/sites-enabled/*;
}
Furthermore, inside the /local/nginx/sites-enabled/ folder I created the following files:
/local/nginx/sites-enabled/example.org,
/local/nginx/sites-enabled/my.example.org.
The content of /local/nginx/sites-enabled/example.org is:
##
# example.org -- Configuration
server {
listen 80;
listen [::]:80;
root /var/www/html;
# Add index.php to the list if you are using PHP
index index.html index.htm index.nginx-debian.html;
server_name example.org;
}
The content of /local/nginx/sites-enabled/my.example.org is:
##
# my.example.org -- Configuration
server {
listen 80;
listen [::]:80;
server_name my.example.org;
location / {
proxy_pass http://192.168.1.2:22300/;
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto $scheme;
proxy_set_header X-Forwarded-Protocol $scheme;
proxy_set_header X-Forwarded-Host $http_host;
}
}
I set up portforwarding on my router to the nginx container and it works. (I see the 404 screen of nginx when I go to http://example.org) However, I struggle to set up the reverse proxy for the joplin container. When I try to access http://my.example.org, I get a 510 error message. What am I doing wrong?
The weird thing is, when I replace http://192.168.1.2:22300/ with the ip of my personal pc running a test webpage, I can access it via http://my.example.org. Even when I setup Joplin on my pc it works. Something seems to be wrong with either my nginx or docker setup.

Answer 1

After lots of debugging and googling around I finally found the solution. What one has to do is the following:
Setup nginx with a network inside nginx/docker-compose.yml:
version: '3'
services:
nginx:
image: nginx:latest
ports:
- 8080:80
volumes:
- /local/nginx/nginx.conf:/etc/nginx/nginx.conf
- /local/nginx/sites-enabled:/etc/nginx/sites-enabled
#----------------------------------------
# Setup network my_net
#----------------------------------------
networks:
- my_net
networks:
my_net:
driver: bridge
Make Joplin use the network defined for nginx, and add an extra one for communication to the database. (Plus, setup a name for the Joplin container.)
version: '3'
services:
db:
image: postgres:13.1
#----------------------------------------
# Setup communication to Joplin server
#----------------------------------------
container_name: database
networks:
- joplin_net
#----------------------------------------
volumes:
- /local/joplin:/var/lib/postgresql/data
restart: unless-stopped
environment:
- APP_PORT=22300
- POSTGRES_PASSWORD=********
- POSTGRES_USER=user
- POSTGRES_DB=database
app:
image: joplin/server:2.2.10
#----------------------------------------
# Setup communication to Postgres server
# and nginx
#----------------------------------------
container_name: joplin # This will be the name used by nginx.
networks:
- joplin_net
- nginx_my_net
#----------------------------------------
depends_on:
- db
ports:
- "22300:22300"
restart: unless-stopped
environment:
- APP_PORT=22300
- APP_BASE_URL=http://192.168.1.2:22300/
- DB_CLIENT=pg
- POSTGRES_PASSWORD=********
- POSTGRES_DATABASE=database
- POSTGRES_USER=user
- POSTGRES_PORT=5432
- POSTGRES_HOST=db
#----------------------------------------
# You can replace joplin_net with any
# name you like. However, the name for
# nginx_my_net has to be:
# app folder + '_' + network name
# The nginx application is in the nginx
# folder, therefore the prefix has to be
# 'nginx_'. The network name is 'my_net',
# so this has to be the suffix.
#----------------------------------------
networks:
joplin_net:
driver: bridge
nginx_my_net:
external: true
The /local/nginx/sites-enabled/my.example.org file has to be amended:
##
# my.example.org -- Configuration
server {
listen 80;
listen [::]:80;
server_name my.example.org;
# The next line make nginx use the docker DNS
# to find the Joplin container by its name
# ('joplin').
resolver 127.0.0.11 valid=30;
location / {
# The server name used here has to be the
# one defined using 'container_name' in the
# docker-compose.yml for the application we
# want to proxy to.
proxy_pass http://joplin:22300/;
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto $scheme;
proxy_set_header X-Forwarded-Protocol $scheme;
proxy_set_header X-Forwarded-Host $http_host;
}
}
Hope this saves someone a couple of days of head-scratching.