You should plan to distribute your docker-compose.yml file, or perhaps a simplified version of it, as the standard way to run your combined application. If it requires two images, you'll need to push the two images separately to your repository; don't try to combine them. Do make sure the images are self-contained so you don't need the source code separately from the images to run them.
The docker-compose.yml file should roughly look like:
version: '3.8'
services:
nginx:
image: registry.example.com/nginx:${TAG:-latest}
ports:
- '80:80'
php:
image: registry.example.com/php:${TAG:-latest}
Calling out a couple of things here: I've removed the unnecessary networks: declarations (Compose provides a default network that works fine) and the unnecessary container_name: declarations. I've put in an image: line for each image in place of the build: block, and use an environment variable to inject the image tag. For the php container I've removed the ports: declaration since you probably don't want that externally accessible. Finally, for both containers I've removed the volumes: that override the image contents.
Next to this, put a docker-compose.override.yml file. This is not something you'd distribute. It can say:
version: '3.8'
services:
nginx:
build:
context: .
dockerfile: Dockerfile.nginx
php:
build:
context: .
dockerfile: Dockerfile.php
ports:
- '9000:9000'
If you have both files, Compose merges their settings. So for a developer this adds in the ports: to directly access the PHP-FPM service if required, and build: blocks to explain how to build both images. Since the combined Compose configuration has both build: and image:, docker-compose build will build images with the specified names tagged with your local registry name.
You should have a separate Dockerfile for each image you're building. The Nginx image resembles what you already have; for the PHP-FPM container you need to make sure you COPY the code into the image.
# Dockerfile.nginx
FROM nginx:1.21.6-alpine
COPY ./src/ /var/www/html/
COPY ./nginx/conf.d/app.conf /etc/nginx/conf.d/app.conf
# Dockerfile.php
FROM php:7.4-fpm-alpine
COPY ./src/app/ /var/www/html/app/
Now you can build and run the application locally. Double-check that it works correctly, without volumes: overwriting the image code.
docker-compose build
docker-compose up -d
curl http://localhost/
If this works, then you're set to distribute this. Pick a tag (a date stamp or the current source control ID are good choices), build the images, and push them to a Docker registry.
export TAG=20220418
docker-compose build
docker-compose push
Now you can copy only the docker-compose.yml file, but none of the other files we've touched, to the remote system, or put it in a GitHub repository, or something else. On that system, set $TAG to match, and run docker-compose up as usual. Docker will automatically pull the images from the repository. Since the images are self-contained, the only thing you need is the docker-compose.yml file.
scp docker-compose.yml there:
ssh root@there
export TAG=20220418
docker-compose up -d
