Grav container not accessible from SWAG container

[jay]

I’m trying to serve Grav from the Linuxserver Grav container (port 80 mapped to 8080) from nginx running in a SWAG container, but I get a 502 Bad Gateway error.

Both containers are running on a VPS with domain vps.domain.com.

I can access the Grav instance if I access the container’s port directly, i.e. vps.domain.com:8080.

I can ping the Grav container from the SWAG container (“ping grav”), but I get “connection refused” if I try to curl the Grav container on the exposed port (curl grav:8080).

I can successfully curl the SWAG container from the Grav container (curl swag:80).

Any suggestions on how to troubleshoot this?

[aptalca]

SWAG setup

[jay]

I’ve checked all the common reasons for 502 listed in that document:

• both containers are in the same docker compose yaml, so they are on the same network
• the container names are the default grav and swag
• I made sure the external port I specified in the docker compose yaml matches with the one specified in the nginx config file
• the contents of the /config/nginx/resolver.conf file is “resolver 127.0.0.11 valid=30s;” as expected

Here is the grav block of my docker compose file:

grav:
image: lscr.io/linuxserver/grav:latest
container_name: grav
environment:
- PUID=1000
- PGID=1000
- TZ=America/Vancouver
volumes:
- appdata/grav:/config
ports:
- 4443:443
- 8080:80
restart: unless-stopped

And here is the location block of the relevant proxy config file:

    include /config/nginx/proxy.conf;
    include /config/nginx/resolver.conf;

    set $upstream_app grav;
    set $upstream_port 8080;
    set $upstream_proto http;

    proxy_pass $upstream_proto://$upstream_app:$upstream_port;

[driz]

Change upstream_port back to 80 and restart, that will fix it

Note that this is exactly what bullet 3 says, you manually changed the port in the config. You shouldn’t have

[jay]

Ah I completely misunderstood the meaning of that bullet point

I did more reading and now understand that it’s the internal container port that needs to be defined as $upstream_port since it’s connecting to the container directly.

Thanks to all for setting me straight!

[driz]

All good, we are all learning! Glad you got it sorted