CODEWITHSUNDEEP
dockerdocker-composedockerfiledocker-network
J.Doe
J.Doe

Reputation: 199

docker-compose connecting two apps

I am trying to link two applications with docker compose I have the following yaml file

version: '3'
services:
 app1:
   build: 
     context: ../../repos/app1
   ports:
     - "8080:8080"
 app2:
   build: .
   ports:
     - "8081:8080"

I know that he ports are arranged as the following host_port:container_port - https://docs.docker.com/compose/networking/

This stack overflow is what made me specify the ports so that the containers are on the same container port. Multiple docker containers with same container port connected to the same network

Then I run a docker compose up

I see two images created and two processes running

REPOSITORY               TAG       IMAGE ID       CREATED      SIZE
main_app2   latest    1d204754b5c3   5 days ago   725MB
main_app1     latest    58e838149b97   5 days ago   754MB
PS C:\Users\am818j\repos\main> docker ps
CONTAINER ID   IMAGE                    COMMAND                  CREATED         STATUS         PORTS                                                           NAMES
d6b6c3411670   main_app2   "/opt/jboss/wildfly/…"   8 minutes ago   Up 8 minutes   8443/tcp, 9990/tcp, 0.0.0.0:8081->8080/tcp, :::8081->8080/tcp   main_app2_1
392e8d6da3c7   main_app1     "/opt/jboss/wildfly/…"   8 minutes ago   Up 8 minutes   8443/tcp, 0.0.0.0:8080->8080/tcp, :::8080->8080/tcp, 9990/tcp   main_app1_1

I can see two processes running and access them from the following urls http://localhost.test.com:8081/app2/faces/home.faces and http://localhost.test.com:8080/app1/faces/home.faces

But I do not see data flow between app1 and app2. Is it possible to have these two apps communicate with each other? If so what am I missing to be able to test that communication?

Upvotes: 1

Views: 1235

Answers (1)

Paul Becotte
Paul Becotte

Reputation: 9997

You say absolutely nothing about the processes. Are they TRYING to communicate with each other? How? What's the error message?

I am guessing you have them trying to talk to localhost:8000 and localhost:8001. However, each container has its OWN localhost loopback- they don't share one. Instead, they should be talking to app1:8000 and app2:8000. Note 8000 vs 8001 - the ports argument maps a port on YOUR interface to a port in THE CONTAINER interface... so far as the container is concerned, it is still listening on port 8000, and your other containers will have to use that.

Upvotes: 1

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