CODEWITHSUNDEEP
dockerdocker-swarm
jhonatan teixeira
jhonatan teixeira

Reputation: 800

docker swarm container communication

I create a swarm and join a node, very nice all works fine

docker swarm init --advertise-addr 192.168.99.1

docker swarm join --token verylonggeneratedtoken 192.168.99.1:2377

I create 3 services on the swarm manager

docker service create --replicas 1 --name nginx nginx --publish published=80,target=80

docker service create --replicas 1 --name php php:7.1-fpm published=9000,target=9000

docker service create --replicas 1 --name postgres postgres:9.5 published=5432,target=5432

All services boots up just fine, but if I customize the php image with my app, and configure nginx to listen to the php fpm socket I can’t find a way to communicate these three services. Even if I access the services using “docker exec -it service-id bash” and try to ping the container names or host names (I even tried to curl them).

What I am trying to say is I don’t know how to configure nginx to connect to fpm since I don’t know how one container communicates to another using swarm. Using docker-compose or docker run is simple as using a links option. I’ve read all documentation around, spent hours on trial and error, and I just couldn’t wrap my head around this. I have read about the routing mesh, wish will get the ports published and it really does to the outside world, but I couldn’t figure in wish ip its published for the internal containers, also that can't be an random ip as that will cause problems to manage my apps configuration, even the nginx configurations.

Upvotes: 2

Views: 864

Answers (3)

Italo Santos
Italo Santos

Reputation: 11

Or you can just make 1 Docker-compose, and make a docker stack with them.

Upvotes: 1

BMitch
BMitch

Reputation: 264986

To have multiple containers communicate with each other, they next to be running on a user created network. With swarm mode, you want to use an overlay network so containers can run on multiple hosts.

docker network create -d overlay mynet

Then run the services with that network:

docker service create --network mynet ...

The easier solution is to use a compose.yml file to define each of the services. By default, the services in a stack are deployed on their own network:

docker stack deploy -c compose.yml stack-name

Upvotes: 2

Bret Fisher
Bret Fisher

Reputation: 8626

It's easier and more reliable to combine php_fpm and nginx in the same image. I know this goes against the official way of single-app images, but for cases like php_fpm+nginx where you must have both to return a request, it's the best case. I have a WIP sample here: https://github.com/BretFisher/php-docker-good-defaults

Upvotes: 0

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