Summary:
I want to be able to get config.template files in InitContainer from Container.

The existing state:
There are template configuration files, that rarely change and contains PlaceHolders, stored inside the image of the container.
When we create the container in the kubernetes there is a script stored also in the image that run and replace all the PlaceHolders with the real values and then start the service.

The desired state:
Having a Init-Container that built from generic image with generic code that need to get as arguments only the directories of the template files (as array of directories) and when it run it take all the template files from the container's image (throw volume), replace the PlaceHolders with the real value and create a final configuration files in a volume that shared with the container. That way the Init-Container do the preparations and when it done the Container need to start immediately with the prepared configuration files. also, the same image of the Init-Container can be used in pods with other containers.

The Problem:
The Init-Container is start first and the volume that map to the Container image and supposed to contain the config.template files is still empty when the Init-Container is running.

My Questions:

• Is there an easy and good way to get those config.template files from the container image from the Init-Container before the container in running?
• Is there a better solution for this problem to get the same or similar result?