I am having this weird error using Postgres with Docker. So, I have two services in my docker-compose file:

version: '3'
services:
  db:
    image: postgres
    restart: always
    ports:
      - '5432:5432'
    environment:
      POSTGRES_PASSWORD: pass123

  test-db:
    image: postgres
    restart: always
    ports:
      - '5433:5433'
    environment:
      POSTGRES_PASSWORD: pass123

So, when I run "docker-compose up -d", both containers get mounted. The command "docker ps" gives me:

CONTAINER ID   IMAGE      COMMAND                  CREATED         STATUS         PORTS                                                 NAMES
a76fcc56f928   postgres   "docker-entrypoint.s…"   6 seconds ago   Up 5 seconds   0.0.0.0:5432->5432/tcp, :::5432->5432/tcp             nodejs-nest_iluvcoffe_db_1
9ab54557063f   postgres   "docker-entrypoint.s…"   6 seconds ago   Up 5 seconds   5432/tcp, 0.0.0.0:5433->5433/tcp, :::5433->5433/tcp   nodejs-nest_iluvcoffe_test-db_1

When i try to connect to the container mapping the port 5432->5432, is all good. But when i try to connect to the container mapping the port 5433->5433 I get the error:

server closed the connection unexpectedly This probably means the server terminated abnormally before or while processing the request.

But, if I map the ports like:

version: '3'
services:
  db:
    image: postgres
    restart: always
    ports:
      - '5432:5432'
    environment:
      POSTGRES_PASSWORD: pass123

  test-db:
    image: postgres
    restart: always
    ports:
      - '5433:5432'
    environment:
      POSTGRES_PASSWORD: pass123

Then, I will have in my "docker ps":

CONTAINER ID   IMAGE      COMMAND                  CREATED         STATUS         PORTS                                       NAMES
5228461a2cff   postgres   "docker-entrypoint.s…"   6 seconds ago   Up 5 seconds   0.0.0.0:5432->5432/tcp, :::5432->5432/tcp   nodejs-nest_iluvcoffe_db_1
39353d05004c   postgres   "docker-entrypoint.s…"   6 seconds ago   Up 5 seconds   0.0.0.0:5433->5432/tcp, :::5433->5432/tcp   nodejs-nest_iluvcoffe_test-db_1

And I can connect to both containers/postgres-servers. Someone know why that? why I cant use the 5433->5433 ports mapping?

CodePudding user response：

• Postgresql service listens on port 5432 within your container.
• ports section with 5433->5432 means map host port 5433 to listening container port 5432

  As a result, mapping 5433 on 5433 is not possible without changing port listening inside postgresql container.

• Each container is like a single host, modifying listening port within posgresql container should not be necessary.

Please check this documentation for more information on postgresql default settings : https://www.postgresql.org/docs/current/runtime-config-connection.html

CodePudding user response：

I believe i understood what is happening. Inside the container, by default, postgres will run on port 5432, even if i map on the ports directive:

ports:
      - '5433:5433'

To tell postgres which port to run inside the container, i used the setup below:

version: '3'
services:
  db:
    image: postgres
    restart: always
    ports:
      - '5432:5432'
    environment:
      POSTGRES_PASSWORD: pass123

  test-db:
    image: postgres
    restart: always
    ports:
      - '5433:5433'
    environment:
      POSTGRES_PASSWORD: pass123
    command: -p 5433

And everything is working now