Postgres docker container still listening at 5432 after port mapping

Background: I'm trying to configure a local dev instance of a service with two docker postgres containers: one for dev and one that I can run pytest integration tests on. The app is built using fastapi and sqlalchemy with asyncpg.

I've got a couple issues here: the first is a problem running my healthcheck, and the second is that I've instructed the postgres container to listen at port 5433 instead of port 5432, but docker ps still shows the container has an active port at 5432. I think this is causing problems trying to connect to this test container. Note the unhealthy status as determined by healthcheck:

Note the healthcheck test line below: when the -u inclasstoday flag is included, it yields an unhealthy status above. However, if I connect to the docker container from my local machine (using docker-exec it test-db sh and then run the same command pg_isready -p 5433 -u inclasstoday, I get the following error:

/ # pg_isready -p 5433
/var/run/postgresql:5433 - accepting connections
/ # pg_isready -p 5433 -u inclasstoday
/usr/local/bin/pg_isready: unrecognized option: u
pg_isready: hint: Try "pg_isready --help" for more information.

However, connecting with only pg_isready -p 5433 works. When I try to edit my docker-compose.yml file to just use this command as a healthcheck, I then get the error:
test-db | 2023-08-08 19:30:47.520 UTC [196] FATAL: role "root" does not exist
Also note that this db log output is caused by the above pg_isready -p 5433 command executed inside the docker container from my local machine.

Included my docker-compose.yml file and a log dump below.

Docker-compose.yml

version: "3.8"
services:
backend:
build: ./backend
environment:
- POSTGRES_USER=fastapi_traefik
- POSTGRES_PASSWORD=password
- POSTGRES_DB=fastapi_traefik
- APP_CONFIG_FILE=local
command: bash -c 'while !</dev/tcp/db/5432; do sleep 1; done; cd backend; echo "RUNNING ALEMBIC MIGRATIONS"; alembic upgrade head; cd ..; uvicorn backend.main:app --host 0.0.0.0 --port 80 --reload'
ports:
- 80:80
volumes:
- .:/app
depends_on:
db:
condition: service_healthy
secrets:
- db_password
networks:
- dock-db-test
db:
image: postgres:15-alpine
container_name: dev-db
volumes:
- postgres_data:/var/lib/postgresql/data/
environment:
- POSTGRES_USER=fastapi_traefik
- POSTGRES_PASSWORD=password
- POSTGRES_DB=fastapi_traefik
ports:
- 5432:5432
restart: unless-stopped
healthcheck:
test: [ "CMD-SHELL", "pg_isready -U fastapi_traefik" ]
interval: 5s
timeout: 5s
retries: 5
secrets:
- db_password
networks:
- dock-db-test
test_db:
image: postgres:15-alpine
container_name: test-db
environment:
- POSTGRES_USER=inclasstoday
- POSTGRES_PASSWORD=inclasstoday1
- POSTGRES_DB=student-data_test
- APP_CONFIG_FILE=test
- POSTGRES_HOST_AUTH_METHOD="trust"
restart: unless-stopped
volumes:
- postgres_data_test:/var/lib/postgresql/data/
ports:
- 5433:5433
healthcheck:
test: [ "CMD-SHELL", "pg_isready -p 5433 -u inclasstoday" ]
interval: 5s
timeout: 5s
retries: 5
networks:
- dock-db-test
command: postgres -c port=5433
volumes:
postgres_data:
postgres_data_test:
secrets:
db_password:
file: db.password.txt
networks:
dock-db-test:
external: false
name: dock-db-test

Log dump:

➜  travelapp git:(async) ✗ docker-compose up
Starting dev-db  ... done
Starting test-db ... done
Starting travelapp_backend_1 ... done
Attaching to dev-db, test-db, travelapp_backend_1
dev-db     |
dev-db     | PostgreSQL Database directory appears to contain a database; Skipping initialization
dev-db     |
dev-db     | 2023-08-08 19:29:41.618 UTC [1] LOG:  starting PostgreSQL 15.3 on x86_64-pc-linux-musl, compiled by gcc (Alpine 12.2.1_git20220924-r10) 12.2.1 20220924, 64-bit
dev-db     | 2023-08-08 19:29:41.622 UTC [1] LOG:  listening on IPv4 address "0.0.0.0", port 5432
dev-db     | 2023-08-08 19:29:41.623 UTC [1] LOG:  listening on IPv6 address "::", port 5432
dev-db     | 2023-08-08 19:29:41.630 UTC [1] LOG:  listening on Unix socket "/var/run/postgresql/.s.PGSQL.5432"
dev-db     | 2023-08-08 19:29:41.660 UTC [62] LOG:  database system was interrupted; last known up at 2023-08-08 19:25:12 UTC
dev-db     | 2023-08-08 19:29:41.878 UTC [62] LOG:  database system was not properly shut down; automatic recovery in progress
dev-db     | 2023-08-08 19:29:41.884 UTC [62] LOG:  redo starts at 0/19A0F80
dev-db     | 2023-08-08 19:29:41.885 UTC [62] LOG:  invalid record length at 0/19A0FB8: wanted 24, got 0
dev-db     | 2023-08-08 19:29:41.885 UTC [62] LOG:  redo done at 0/19A0F80 system usage: CPU: user: 0.00 s, system: 0.00 s, elapsed: 0.00 s
dev-db     | 2023-08-08 19:29:41.891 UTC [58] LOG:  checkpoint starting: end-of-recovery immediate wait
dev-db     | 2023-08-08 19:29:41.902 UTC [58] LOG:  checkpoint complete: wrote 3 buffers (0.0%); 0 WAL file(s) added, 0 removed, 0 recycled; write=0.004 s, sync=0.001 s, total=0.012 s; sync files=2, longest=0.001 s, average=0.001 s; distance=0 kB, estimate=0 kB
dev-db     | 2023-08-08 19:29:41.916 UTC [1] LOG:  database system is ready to accept connections
test-db    |
test-db    | PostgreSQL Database directory appears to contain a database; Skipping initialization
test-db    |
test-db    | 2023-08-08 19:29:41.759 UTC [1] LOG:  starting PostgreSQL 15.3 on x86_64-pc-linux-musl, compiled by gcc (Alpine 12.2.1_git20220924-r10) 12.2.1 20220924, 64-bit
test-db    | 2023-08-08 19:29:41.762 UTC [1] LOG:  listening on IPv4 address "0.0.0.0", port 5433
test-db    | 2023-08-08 19:29:41.762 UTC [1] LOG:  listening on IPv6 address "::", port 5433
test-db    | 2023-08-08 19:29:41.767 UTC [1] LOG:  listening on Unix socket "/var/run/postgresql/.s.PGSQL.5433"
test-db    | 2023-08-08 19:29:41.783 UTC [62] LOG:  database system was shut down at 2023-08-08 19:27:17 UTC
test-db    | 2023-08-08 19:29:41.804 UTC [1] LOG:  database system is ready to accept connections
backend_1  | RUNNING ALEMBIC MIGRATIONS
backend_1  | INFO  [alembic.runtime.migration] Context impl PostgresqlImpl.
backend_1  | INFO  [alembic.runtime.migration] Will assume transactional DDL.
backend_1  | INFO:     Will watch for changes in these directories: ['/app']
backend_1  | INFO:     Uvicorn running on http://0.0.0.0:80 (Press CTRL+C to quit)
backend_1  | INFO:     Started reloader process [12] using WatchFiles
backend_1  | INFO:     Started server process [14]
backend_1  | INFO:     Waiting for application startup.
backend_1  | INFO:     Application startup complete.
test-db    | 2023-08-08 19:30:47.520 UTC [196] FATAL:  role "root" does not exist
test-db    | 2023-08-08 19:33:55.982 UTC [538] FATAL:  role "root" does not exist
test-db    | 2023-08-08 19:34:41.809 UTC [58] LOG:  checkpoint starting: time
test-db    | 2023-08-08 19:34:41.879 UTC [58] LOG:  checkpoint complete: wrote 3 buffers (0.0%); 0 WAL file(s) added, 0 removed, 0 recycled; write=0.017 s, sync=0.003 s, total=0.070 s; sync files=2, longest=0.002 s, average=0.001 s; distance=0 kB, estimate=0 kB

Expected the postgres port to no longer be accepting connections at port 5432 for test-db, and to be able to connect using the user -u flag in ps_isready.

You are passed an invalid parameter. You passed -u (with lowercase), the correct one is -U (with uppercase). Also, you can pass a database name.
Try the following command:

test: [ "CMD-SHELL", "pg_isready -p 5433 -U inclasstoday -d student-data_test" ]