ports not open with userns=keep-id

[hadmut]

Hi,

I am currently trying to cope with the problem that I cannot run rails applications ( postgres + rails ) with podman-compose when running as non-root with env set to PODMAN_USERNS=keep_id

Using ubuntu 22.04 with podman 3.4.4 and latest podman-compose installed with
pip3 install https://github.com/containers/podman-compose/archive/devel.tar.gz

Using a docker-compose.yaml with
services:
application:
image: alpine
command: sh -c "nc -l -p 4000 </dev/null"
ports:
- "4000:4000"

and docker-compose up works the same way: It waits, and once the command is issued, it prints a date and terminates.

But when doing
PODMAN_USERNS=keep-id podman-compose up

with the USERNS variable, nothing works anymore.

Any reason known for this?

regards

I've tracked this down to this test scenario:

Running either

podman run --rm --userns=keep-id -it -p 4000:4000 alpine sh -c "nc -l -p 4000 </dev/null"

or
PODMAN_USERNS=keep-id podman run --rm --userns=keep-id -it -p 4000:4000 alpine sh -c "nc -l -p 4000 </dev/null"

work as expected. A command
date | nc 127.0.0.1 4000
opens a tcp connection into the container, the container then prints the date string and terminates.

Same with podman