从Docker容器连接到另一个Docker容器的端口

Question

I have two docker containers running on a linux host.

One with a DATABASE and one with an APPLICATION.

How can I connect from container APPLICATION to container DATABASE port 5432?

For example: I start DATABASE container and bind port 5432 to hosts localhost with "-p5432:5432. But how can I acces this port from APPLICATION? I cannot bind port 5432 to host localhost because this port is now already used.

Docker version 1.12.6

update

I used now

sudo docker network create --subnet=172.20.0.0/16 --gateway=172.20.0.100   --ip-range=172.20.1.0/24 my-network
sudo docker run --name postgres  --network=my-network --ip=172.20.0.10 -d postgres
sudo docker run --name application --network=my-network --ip=172.20.0.15 -d application

and configured app in APPLICATION container to look for ip 172.20.0.10

https://docs.docker.com/engine/userguide/networking/work-with-networks/

Answer 1

Alternatively you can use docker networks, easy to achieve with docker-compose . In my example you can point from your app container to postgres-container as this: postgres-container:5432

docker-compose.yml:

version: "3"

services:
  app:
    image: postgres
    command: sh -c 'sleep 10; echo \\l | PGPASSWORD=mysecretpassword psql -U postgres -h postgres-container'
  postgres-container:
    image: postgres
    environment:
      - POSTGRES_PASSWORD=mysecretpassword

Command:

docker-compose up

Output:

Attaching to postgresql_app_1, postgresql_postgres-container_1
(...)
postgres-container_1  | server started
(...)
app_1                 |                                  List of databases
app_1                 |    Name    |  Owner   | Encoding |  Collate   |   Ctype    |   Access privileges
app_1                 | -----------+----------+----------+------------+------------+-----------------------
app_1                 |  postgres  | postgres | UTF8     | en_US.utf8 | en_US.utf8 |
app_1                 |  template0 | postgres | UTF8     | en_US.utf8 | en_US.utf8 | =c/postgres          +
app_1                 |            |          |          |            |            | postgres=CTc/postgres
app_1                 |  template1 | postgres | UTF8     | en_US.utf8 | en_US.utf8 | =c/postgres          +
app_1                 |            |          |          |            |            | postgres=CTc/postgres
app_1                 | (3 rows)
app_1                 |

Answer 2

1. You can use docker link to link to running containers ... like below and use alias name as ip address. You can do same using docker-compose as well.

   $ docker run -d -P --name application --link db-image:db application-image

use 'db' as host name in your application.

2. You can also give your host ip to application container as db end point. It will work.