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[Solved] Could not translate host name “db” to address using Postgres, Docker Compose and Psycopg2

Hello Guys, How are you all? Hope You all Are Fine. Today I get the following error Could not translate host name “db” to address using Postgres, Docker Compose and Psycopg2 in python. So Here I am Explain to you all the possible solutions here.

Without wasting your time, Let’s start This Article to Solve This Error.

How Could not translate host name “db” to address using Postgres, Docker Compose and Psycopg2 Error Occurs?

Today I get the following error Could not translate host name “db” to address using Postgres, Docker Compose and Psycopg2 in python.

How To Solve Could not translate host name “db” to address using Postgres, Docker Compose and Psycopg2 Error ?

  1. How To Solve Could not translate host name “db” to address using Postgres, Docker Compose and Psycopg2 Error ?

    To Solve Could not translate host name “db” to address using Postgres, Docker Compose and Psycopg2 Error The problem is you should not be running python base.py as part of the RUN directive.

  2. Could not translate host name “db” to address using Postgres, Docker Compose and Psycopg2

    To Solve Could not translate host name “db” to address using Postgres, Docker Compose and Psycopg2 Error The problem is you should not be running python base.py as part of the RUN directive.

Solution 1

The problem is you should not be running python base.py as part of the RUN directive.

The RUN directive is executed only when you are building the image. The postgres container is not running at this point, nor has the network been created. Instead you want to use the CMD directive.

Change the Dockerfile to this:

FROM ubuntu:16.04

RUN apt-get update
RUN apt-get -y install python-pip
RUN apt-get update
RUN pip install --upgrade pip
RUN pip install psycopg2-binary

COPY base.py base.py

CMD ["python", "base.py"]

The above should result in the hostname db to be resolved. However if your python code doesn’t have any reconnection logic for connecting to the database the container will likely still error out. This because the postgres container will be running but the database won’t be ready to accept connections.

This can be temporarily fixed by adding restart: always to your docker-compose.yml.

version: '3'
services:
  db:
    image: 'postgres:latest'
    expose:
      - "5432"
    environment:
      POSTGRES_PASSWORD: pw1234
      POSTGRES_DB: base123
  aprrka:
    restart: always
    build: .    
    depends_on:
      - db

Hopefully this will get you up and running.

Solution 2


If you’re using docker-compose first add this line to your .yml:

environment:
  - "POSTGRES_HOST_AUTH_METHOD=trust"

After that you start only you db docker:

docker-compose up db

It should start normally with a message like:

Recreating db... done
Attaching to db
db_1           | ********************************************************************************
db_1           | WARNING: POSTGRES_HOST_AUTH_METHOD has been set to "trust". This will allow
db_1           |          anyone with access to the Postgres port to access your database without
db_1           |          a password, even if POSTGRES_PASSWORD is set. See PostgreSQL
db_1           |          documentation about "trust":
db_1           |          https://www.postgresql.org/docs/current/auth-trust.html
db_1           |          In Docker's default configuration, this is effectively any other
db_1           |          container on the same system.
db_1           | 
db_1           |          It is not recommended to use POSTGRES_HOST_AUTH_METHOD=trust. Replace
db_1           |          it with "-e POSTGRES_PASSWORD=password" instead to set a password in
db_1           |          "docker run".
db_1           | ********************************************************************************

Summery

It’s all About this issue. Hope all solution helped you a lot. Comment below Your thoughts and your queries. Also, Comment below which solution worked for you? Thank You.

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