SOLUTION:

The issue was - the ‘New UI’ docker image was automatically building for AMD64, but the Linux server is an ARM64/v8.

I had to add QEMU and multi-platform build commands to the docker-image.yml file (in Github Actions).

This creates an additional docker image for ARM64 machines, which loads and runs successfully.

This was discovered by manually building a docker container, and receiving the following message: WARNING: The requested image's platform (linux/amd64) does not match the detected host platform (linux/arm64/v8) and no specific platform was requested

So if you get that message, you must build your docker image for the platform you are on (or multiple platforms).

** == ** == ** == ** == ** == ** == **

ORIGINAL ERROR:

THE SETUP and ERROR

1. I made a fresh ansible install, on a fresh ubuntu 20.04 server - the Lemmy instance runs perfectly.
2. I made a fresh fork of the 16.7 Lemmy-UI.
3. I built a docker-image of that forked UI, and loaded it via docker-compose (here is my docker-image.yml build file ).

Now I am getting a “502 Bad Gateway - nginx” error (the site does not load).

NGINX error log shows:

connect() failed (111: Connection refused) while connecting to upstream, client: 75.222.232.212, server: ggg.com, request: "GET / HTTP/2.0", upstream: "http://0.0.0.0:15153/", host: "ggg.com"

• Nginx config has not been modified (but here is the config anyway - ggg.conf)

• Docker log is clean.

**

DIAGNOSIS

When I list docker containers, there is no PORT mapped to the ‘New-UI’ image container.

(However, when running the ‘default lemmy-UI’ image container, the PORT is successfully mapped to 127.0.0.1:15153->1234/tcp)

It seems I must create a new Container, using the ‘New-UI’ image, and map the PORT to 127.0.0.1:15153->1234/tcp (unless an Environment Variable can do it).

^ Now I must figure out that exact docker command. (because docker run -d -p 127.0.0.1:15153:1234 [ImageID] does not successfully create the container.)

**

Here are the Env Vars I’ve added (in various combinations/values):

  lemmy-ui:
    environment:
      - LEMMY_UI_HTTPS=true
      - LEMMY_UI_LEMMY_INTERNAL_HOST=lemmy:8536
      - LEMMY_UI_LEMMY_EXTERNAL_HOST=ggg.com
      - LEMMY_UI_DISABLE_CSP=true
      # - LEMMY_UI_LEMMY_WS_HOST=lemmy:8536
      # - LEMMY_UI_HOST=0.0.0.0:1234

here is the full docker-compose.yml (only changed Env Vars)