PostgrSQL custom Docker Container - postgresql

Question

I am trying to write a docker entrypoint script, that’s able to start postgreSQL and creating a new named database.
I feel like there is a much better way, than mine. I am happy for every input.
Issues:
a few times I have to restart the container befor it creates the databas and does not crash. Some times I don't know why it workes. I can't recreate it right now.
Freequently I get messages like [unknown]#[unknown] LOG: incomplete startup packet but there shouldn't be any.
Reason for custom docker image: I need PostgreSQL to use ssl for every connection. The official image is sadly not able to allow ssl with real certificates.
Dockerfile:
FROM debian:10.9
RUN apt update && apt install -y \
postgresql postgresql-contrib \
openssl \
net-tools netcat \
vim
RUN mkdir database_stuff
COPY --chown=postgres:postgres ./entrypoint.sh /database_stuff/entrypoint.sh
RUN chmod 777 /database_stuff/entrypoint.sh
COPY --chown=postgres:postgres ./certificates/cert.pem /database_stuff/cert.pem
RUN chmod 600 /database_stuff/cert.pem
COPY --chown=postgres:postgres ./certificates/key.pem /database_stuff/key.pem
RUN chmod 600 /database_stuff/key.pem
COPY --chown=postgres:postgres ./configuration/postgresql.conf /etc/postgresql/11/main/postgresql.conf
COPY --chown=postgres:postgres ./configuration/pg_hba.conf /etc/postgresql/11/main/pg_hba.conf
VOLUME ["/etc/postgresql", "/var/log/postgresql", "/var/lib/postgresql"]
USER postgres
CMD ["/usr/lib/postgresql/11/bin/postgres", "-D", "/var/lib/postgresql/11/main/", "-c", "config_file=/etc/postgresql/11/main/postgresql.conf"]
ENTRYPOINT ["/database_stuff/entrypoint.sh"]
entrypoint.sh script
#!/usr/bin/env bash
echo "START entrypoint.sh"
echo "start postgrSQL"
/usr/lib/postgresql/11/bin/postgres -D /var/lib/postgresql/11/main/ -c config_file=/etc/postgresql/11/main/postgresql.conf &
until nc -z db 5432; do
sleep 0.1
done
echo "create Database"
psql -U postgres -c 'create database part_screening;'
psql -U postgres -c "create user alstom with encrypted password 'Laser765_f';"
echo "END entrypoint.sh .... Stay open"
tail -f /dev/null
just a log with the unknown#unknown issue
START entrypoint.sh
start postgrSQL
create Database
CREATE DATABASE
CREATE ROLE
END entrypoint.sh .... Stay open
2021-08-02 17:08:52.280 UTC [7] LOG: listening on IPv4 address "0.0.0.0", port 5432
2021-08-02 17:08:52.280 UTC [7] LOG: listening on IPv6 address "::", port 5432
2021-08-02 17:08:52.284 UTC [7] LOG: listening on Unix socket "/var/run/postgresql/.s.PGSQL.5432"
2021-08-02 17:08:52.300 UTC [10] LOG: database system was shut down at 2021-08-02 17:06:42 UTC
2021-08-02 17:08:52.305 UTC [7] LOG: database system is ready to accept connections
2021-08-02 17:08:52.330 UTC [18] [unknown]#[unknown] LOG: incomplete startup packet
2021-08-02 17:08:53.145 UTC [38] [unknown]#[unknown] LOG: incomplete startup packet