I am not new to Docker, nor am I an expert but I am currently not able to figure out what I am doing wrong.

The Docker image I am using is the official one from here: https://hub.docker.com/r/openproject/community/ and I have followed those “Quick Start” instructions.

here is what I have done so far:

1. openproject is running on a docker host within my internal LAN at work and is not reachable from the outside, same goes for the email server indicated in the options below
2. docker run -d —name openproject -p 8081:80 -v /mnt/openproject-data:/var/db/openproject -v /mnt/openproject-db:/var/lib/postgresql/9.4/main -e SECRET_KEY_BASE=mysecret -e SMTP_ADDRESS=192.168.220.2 -e SMTP_PORT=25 -e SMTP_DOMAIN=mydomain.tld openproject/community:7
3. I can now access openproject via my docker-host:8081
4. I log in as admin:admin and do the mandatory password change
5. I change some configurations inside the openproject system settings
6. I now realized I made some errors with my first docker installation so I stop, remove and start my container again
7. docker stop openproject
8. docker rm openproject
9. docker run -d —name openproject -p 8081:80 -v /mnt/openproject-data:/var/db/openproject -v /mnt/openproject-db:/var/lib/postgresql/9.4/main -e SECRET_KEY_BASE=mysecret -e SMTP_ADDRESS=192.168.220.2 -e SMTP_PORT=25 -e SMTP_DOMAIN=mydomain.tld openproject/community:7
10. I go to docker-host:8081 and find out that my new password doesn’t work and has reverted to admin:admin and all the changes to system settings I made before are lost

I am unable to figure out what I did wrong, the whole purpose of the two "v" options above was to keep persistent settings :(
-v /mnt/openproject-data:/var/db/openproject -v /mnt/openproject-db:/var/lib/postgresql/9.4/main

The indicated folders both exist and are empty. After running my container /mnt/openproject-data now has a subfolder called files but /mnt/openproject/db is still empty.

Any hints on what I am doing wrong? I don’t want to go ahead and set openproject up properly only to lose all my settings with the next update.

After some debugging, I think I might have found the problem in the logs:

-----> Database cluster not found. Creating a new one in /var/lib/postgresql/9.6/main...
Apparently the Docker iamge does no longer run postgresql 9.4 but 9.6

I am now trying to start the container like this: docker run -d —name openproject -p 8081:80 -v /mnt/openproject-data:/var/db/openproject -v /mnt/openproject-db:/var/lib/postgresql -e SECRET_KEY_BASE=mysecret -e SMTP_ADDRESS=192.168.220.2 -e SMTP_PORT=25 -e SMTP_DOMAIN=mydomain.tld —restart=unless-stopped openproject/community:7

There are no more errors in the docker container logs which I can see:
-----> Database cluster not found. Creating a new one in /var/lib/postgresql/9.6/main... The files belonging to this database system will be owned by user "postgres". This user must also own the server process.
and still the folder /mnt/openproject-db/ only contains the subfolder 9.6 with a subfolder named main which is also empty so where is my persistent DB?