Postgres and Docker Compose; password authentication fails and role 'postgres' does not exist. Cannot connect from pgAdmin4

Question

I have a docker-compose that brings up the psql database as below, currently I'm trying to connect to it with pgAdmin4 (not in a docker container) and be able to view it. I've been having trouble authenticating with the DB and I don't understand why.

docker-compose

version: "3"

services:
  # nginx and server also have an override, but not important for this q.
  nginx:
    ports:
      - 1234:80
      - 1235:443
  server:
    build: ./server
    ports:
      - 3001:3001 # app server port
      - 9230:9230 # debugging port
    env_file: .env
    command: yarn dev
    volumes:
      # Mirror local code but not node_modules
      - /server/node_modules/
      - ./server:/server
  
  database:
    container_name: column-db
    image: 'postgres:latest'
    restart: always
    ports:
      - 5432:5432
    environment:
      POSTGRES_USER: postgres # The PostgreSQL user (useful to connect to the database)
      POSTGRES_PASSWORD: root # The PostgreSQL password (useful to connect to the database)
      POSTGRES_DB: postgres # The PostgreSQL default database (automatically created at first launch)
    volumes:
      - ./db-data/:/var/lib/postgresql/data/

networks:
  app-network:
    driver: bridge

I do docker-compose up then check the logs, and it says that it is ready for connections. I go to pgAdmin and enter the following:

where password is root. I then get this error:

FATAL:  password authentication failed for user "postgres"

I check the docker logs and I see

DETAIL:  Role "postgres" does not exist.

I'm not sure what I'm doing wrong, according to the docs the super user should be created with those specifications. Am I missing something? Been banging my head against this for an hour now. Any help is appreciated!

Answer 1

@jjanes solved it in a comment, I had used a mapped volume and never properly set up the db. Removed the volume and we're good to go.