OSSM-3669: initial changes for interop pipeline support

[FilipB]

We need an image which can be run on OCP. This is first change which is required. It contains also some minor improvements.

[FilipB]

There will be probably more changes, we just need this one merged to be able to start with the interop openshift CI config draft.

[luksa]

But this change prevents you from running the image like this:

podman run <image> TestFaultInjection

You're now forced to do it like this:

podman run <image> scripts/runtests.sh TestFaultInjection

This requires knowledge of the image internals (the name and location of the runtests.sh script).

What exactly do we need to overwrite when using this in OpenShiftCI?

[FilipB]

Yes, I was thinking that using TEST_CASE env variable would be good enough, we can describe this in the Readme to use only env variables when working with the container. My understanding is that in openshiftCI config you specify which commands need to be run in the container. Those commands then overwrite the default CMD. I need to check if it's possible to make it work also when using ENTRYPOINT e.g. via --entrypoint

[luksa]

I think if people end up using the image even when running tests manually (so that they don't have to install any prerequisites), it has to be simple to use (e.g. without the TEST_CASE variable)... but it is true, that they may still want to set other variables...

As for OpenShiftCI: that's exactly the reason why I used ENTRYPOINT instead of CMD - because you will never want to run anything else than runtests.sh, but you may want to set additional arguments via CMD.

[FilipB]

Ok, let's use ENTRYPOINT for now. I still need to understand OpenShift CI better. We can change it later if it's going to be really needed.