3

I define postgres server in docker-compose.yml:

db:
    image: postgres:9.5
    expose:
        - 5432

Then in another docker container I tried to connect to this postgres container. But it gives an error with warning:

Is the server running on host "db" (172.22.0.2) and accepting
data-service_1  |   TCP/IP connections on port 5432?

Why container can't to connect to another by provided information (host="db" and port=5432)?

PS Full docker-compose.yml:

version: "2"
services:
    data-service:
        build: .
        depends_on:
            - db
        ports:
          - "50051:50051"
    db:
        image: postgres:9.5
        depends_on:
            - data-volume
        environment:
            - POSTGRES_USER=cobrain
            - POSTGRES_PASSWORD=a
            - POSTGRES_DB=datasets
        ports:
          - "8000:5432"
        expose:
            - 5432
        volumes_from:
            - data-volume
            # - container:postgres9.5-data
        restart: always

    data-volume:
        image: busybox
        command: echo "I'm data container"
        volumes:
            - /var/lib/postgresql/data
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2
  • please post full docker-compose.yml Commented May 16, 2017 at 0:05
  • @AlexKarshin I added it. Commented May 16, 2017 at 0:11

2 Answers 2

Reset to default
3

Solution #1. Same file.

To be able to access the db container, you have to define your other containers in context of docker-compose.yml. When containers are started, each container gets all other containers mapped in /etc/hosts.

Just do

version: '2'
services:
  web:
    image: your/image
  db:
    image: postgres:9.5

If you do not wish to put your other containers into the same docker-compose.yml, there are other solutions:

Solution #2. IP

Do docker inspect <name of your db container> and look for IPAddress directive in the result listing. Use that IPAddress as host to connect to.

Solution #3. Networks

Make your containers join same network. For that, under each service, define:

services:
  db:
    networks:
     - myNetwork

Don't forget to change db for each container you are starting.

I usually go with the first solution during development. I use apache+php as one container and pgsql as another one, a separate DB for every project. I do not start more than one setting of docker-compose.yml, so in this case defining both containers in one .yml config is perfect.

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6 Comments

But build: . is the same as image: your/image. I can't see difference between solution 1 and mine one.
actually, on closer inspection, I think depends_on might give you problems, because you are defining a recursive dependency
recursive? No, it's just a chain of dependencies data-service --> db --> data-volume.
ah, yes, sorry, it's naming getting mixed up :) I will delete my answer and will try to come up with the right solution
@RomaKarageorgievich what happens if you define expose as string? I.e. - "5432"? All docs define it as string.
|
-1

the depends on is not correct. i would try to use other paramters like LINKS and environment:

version: "2"
    services:
        data-service:
            build: .
            links:
                - db
            ports:
              - "50051:50051"
            volumes_from: ["db"]
            environment:
                DATABASE_HOST: db
        db:
            image: postgres:9.5
            environment:
                - POSTGRES_USER=cobrain
                - POSTGRES_PASSWORD=a
                - POSTGRES_DB=datasets
            ports:
              - "8000:5432"
            expose:
                - 5432
            #volumes_from:
                #- data-volume
                # - container:postgres9.5-data
            restart: always

        data-volume:
            image: busybox
            command: echo "I'm data container"
            volumes:
                - /var/lib/postgresql/data

this one works for me (not postgres but mysql)

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1 Comment

depends_on has nothing to do with getting containers communicate with each other..

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