Postgresql Docker role does not exist

Question

I downloaded the docker container for postgres: https://hub.docker.com/r/library/postgres/, and did the following:

$ docker run --name satgres -e POSTGRES_PASSWORD=mysecretpassword -d -p 5432:5432 postgres
satgres | "docker-entrypoint.s…" | 5 seconds ago | Up 6 seconds | 0.0.0.0:5432->5432/tcp | satgres
$ docker exec -it c8f1b22cc41e /bin/bash        
# psql -U postgres
psql (10.1)
postgres=# CREATE DATABASE mytest;
postgres=# \password postgres
postgres=# CREATE ROLE ming WITH LOGIN PASSWORD 'pass1234';
postgres=# ALTER ROLE ming CREATEDB;
postgres=# CREATE DATABASE sjk;
postgres=# GRANT ALL PRIVILEGES ON DATABASE youtube TO ming;
postgres=# \connect sjk
youtube=# ALTER ROLE ming lOGIN;  

My plan is to use this database on docker with Django, so first want to check I can connect, but I cant.

$ psql -h localhost -p 5432 -U postgres
$ psql: FATAL:  role "postgres" does not exist
$ psql -h localhost -p 5432 -U ming
$ psql: FATAL:  role "ming" does not exist

I do the same with PSequal.app, says the same thing, Im running on Mac High Sierra.

Why am I getting this error? The role exists, or at least it seems it to me...

Answer 1

In my case, the problem may be due also to the use of a super user who is not postgres. Lhe developers chose the user georchestra in the geOrchestra docker composition. Extract from the dockerfile:

environment:
  - POSTGRES_USER=georchestra

HEALTHCHECK --interval=30s --timeout=30s \
  CMD pg_isready -U $POSTGRES_USER

consequently, you will have to use the option "-U georchestra" to connect to the container.

$ docker exec -it docker_database_1 psql -U georchestra
psql (10.5 (Debian 10.5-1.pgdg90+1))
Type "help" for help.

and of course, trying to connect with the user postgres causes an error:

docker exec -it docker_database_1 psql -U postgres
psql: FATAL:  role "postgres" does not exist

Answer 2

The problem was simple enough that my computer was already running an instance of Postgres that I was not aware was still running (not inside Docker) on :5432, checked with:

$ lsof -n -i:5432 | grep LISTEN

So I remembered I installed it via https://gist.github.com/sgnl/609557ebacd3378f3b72, I ran

$ pg-stop

And then I had no problem connecting to the Docker instance.