[RFE] Support config files mount for kolla_dev_mode

[Yang Youseok]

Currently, config files like policy.yml, nova.conf.. are copied when container started. Developer need to deploy config files in deploy node (or locate config files in controller node), and restart docker container when they want to test config related functionalities.

I think it's better to mount config files in container just like project code when dev_mode enabled so that whenever they want to refresh config,
simply can use SIGHUP (policy file even refreshed everytime automatically)

Thanks.

[Mark Goddard (mgoddard)]

This sounds like it would be a lot of work to change. Why is it easier to use SIGHUP than docker restart?

[Yang Youseok (ileixe)]

Hm.. I assume that it's natural to feel easier since it make more time to restart process than just reloading config files. But I realize without me who think fast development iteration important, it will be not a matter.

However except for that matter, I think source of configuration should be located just in one place. I understand kolla attach volume to container and copy configuration files to original config location. I felt it's little bit confusing in that after I edit configuration in the volume location, it does not take effect. After looking for the related code, I realized config files copied in the wrapper script which is against intuition.

This may be because I do not have a technical background. If then please let me know.

Thanks.