How to fix error "Error: Database is uninitialized and superuser password is not specified."

You can use the POSTGRES_HOST_AUTH_METHOD environment property by making the following change to your docker-compose.yml.

db:
    image: postgres:9.6-alpine
    environment:
      POSTGRES_DB: "db"
      POSTGRES_HOST_AUTH_METHOD: "trust"

The above will solve the error.

To avoid that you can specify the followings environments variables for postgres container on your docker-compose file.

POSTGRES_PASSWORD This environment variable is normally required for you to use the PostgreSQL image. This environment variable sets the superuser password for PostgreSQL. The default superuser is defined by the POSTGRES_USER environment variable.

POSTGRES_DB This optional environment variable can be used to define a different name for the default database that is created when the image is first started. If it is not specified, then the value of POSTGRES_USER will be used.

For more information about Environment Variables check: https://hub.docker.com/_/postgres

It's already mentioned in the interactive mode; how to run the container, if you don't find it, use the following:

To allow all connections without a password use:

• docker run -e POSTGRES_HOST_AUTH_METHOD=trust postgres:9.6 (use the tag you need).

To specify postgres password for the superuser, use:

• docker run -e POSTGRES_PASSWORD=<your_password> postgres:9.6 (use the tag you need).