How can I fix docker networking issues with multiple containers when working locally

andreas

1/25/24, 12:26 AM

So I have a basic docker setup with nginx and php-fpm that gets deployed to AWS ECS:

Dockerfile for nginx

# Install nginx
FROM --platform=linux/amd64 nginx:latest

# Use custom configs
ADD nginx/conf/nginx.conf /etc/nginx/conf.d/default.conf

Nginx config file

server {

    server_name localhost;

    root /usr/share/nginx/html/public;
    index index.php;

    location / {
        try_files $uri $uri/ /index.php?$query_string;
    }

    location ~ \.php$ {
        fastcgi_split_path_info ^(.+\.php)(/.+)$;
        fastcgi_pass localhost:9000;
        fastcgi_index index.php;
        include fastcgi_params;
        fastcgi_param REQUEST_URI $request_uri;
        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
        fastcgi_param PATH_INFO $fastcgi_path_info;
    }

}

Dockerfile for php-fpm

# Install nginx
FROM --platform=linux/amd64 php:8.1-fpm

# Add the files
COPY dist /usr/share/nginx/html

Question

Note: This setup works well when I deploy to AWS.

But when I try the images locally, it does not work (Bad Gateway) because the nginx container does not find localhost:9000 defined in the nginx config. I have to use localhost due to the AWSVPC network mode.

How can I also make it work locally without editing too many things? Is there a config option when I run the containers locally? Right now, I run them like this:

docker run -p 8001:80 -d --name $DEPLOY_NAME_NGINX $DEPLOY_NAME_NGINX
docker run -d --name $DEPLOY_NAME_PHP_FPM $DEPLOY_NAME_PHP_FPM

390

0 + 5

nginx

php-fpm

amazon-web-services

docker

docker-networking

Tom Yan

1/25/24, 8:08 AM

I think you need `--network="host"` for at least the nginx `docker run` command and a `-p` that maps port 9000 of the docker host to the port the php-fpm listens inside its container. (Or maybe, if that's also 9000, just use `--network="host"` for both `docker run` commands.) See [this answers](https://stackoverflow.com/a/24326540) for more details.

andreas

1/25/24, 7:59 PM

This was a good idea but I found that the host network option does not work on MacOS (we work mostly on Mac at this time for development).

Tom Yan

1/25/24, 8:10 PM

Well, obviously the simplest alternative would be to replace `localhost` with the IP of the php-fpm container, assuming the two containers can communicate with each other (e.g. connected to the same bridge).

andreas

1/25/24, 8:54 PM

I tried that (successfully), but the communication then breaks on AWS. It seems that on the VPC that AWS generates the local IPs are different...

Tom Yan

1/26/24, 1:32 AM

Yeah I don't expect you can have entirely portable configs if you can't `docker run` identically on different places. Not familiar enough with docker to tell what exactly are the "best practices" to deal with this kind of problem.

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