How to correctly link php-fpm and Nginx Docker containers?

Solution 1:

I know it is kind an old post, but I've had the same problem and couldn't understand why your code didn't work. After a LOT of tests I've found out why.

It seems like fpm receives the full path from nginx and tries to find the files in the fpm container, so it must be the exactly the same as server.root in the nginx config, even if it doesn't exist in the nginx container.

To demonstrate:

docker-compose.yml

nginx:
    build: .
    ports:
        - "80:80"
    links:
        - fpm
fpm:
    image: php:fpm
    ports:
        - ":9000"

    # seems like fpm receives the full path from nginx
    # and tries to find the files in this dock, so it must
    # be the same as nginx.root
    volumes:
        - ./:/complex/path/to/files/

/etc/nginx/conf.d/default.conf

server {
    listen  80;

    # this path MUST be exactly as docker-compose.fpm.volumes,
    # even if it doesn't exist in this dock.
    root /complex/path/to/files;

    location / {
        try_files $uri /index.php$is_args$args;
    }

    location ~ ^/.+\.php(/|$) {
        fastcgi_pass fpm:9000;
        include fastcgi_params;
        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
    }
}

Dockerfile

FROM nginx:latest
COPY ./default.conf /etc/nginx/conf.d/

Solution 2:

Don't hardcode ip of containers in nginx config, docker link adds the hostname of the linked machine to the hosts file of the container and you should be able to ping by hostname.

EDIT: Docker 1.9 Networking no longer requires you to link containers, when multiple containers are connected to the same network, their hosts file will be updated so they can reach each other by hostname.

Every time a docker container spins up from an image (even stop/start-ing an existing container) the containers get new ip's assigned by the docker host. These ip's are not in the same subnet as your actual machines.

see docker linking docs (this is what compose uses in the background)

but more clearly explained in the docker-compose docs on links & expose

links

links:
 - db
 - db:database
 - redis

An entry with the alias' name will be created in /etc/hosts inside containers for this service, e.g:

172.17.2.186  db
172.17.2.186  database
172.17.2.187  redis

expose

Expose ports without publishing them to the host machine - they'll only be accessible to linked services. Only the internal port can be specified.

and if you set up your project to get the ports + other credentials through environment variables, links automatically set a bunch of system variables:

To see what environment variables are available to a service, run docker-compose run SERVICE env.

name_PORT

Full URL, e.g. DB_PORT=tcp://172.17.0.5:5432

name_PORT_num_protocol

Full URL, e.g. DB_PORT_5432_TCP=tcp://172.17.0.5:5432

name_PORT_num_protocol_ADDR

Container's IP address, e.g. DB_PORT_5432_TCP_ADDR=172.17.0.5

name_PORT_num_protocol_PORT

Exposed port number, e.g. DB_PORT_5432_TCP_PORT=5432

name_PORT_num_protocol_PROTO

Protocol (tcp or udp), e.g. DB_PORT_5432_TCP_PROTO=tcp

name_NAME

Fully qualified container name, e.g. DB_1_NAME=/myapp_web_1/myapp_db_1