Multiple independent kernel modules deployment via single KMM Module

[yevgeny-shnaidman]

Currently KMM supports 2 mode for deploying kernel module/s via single KMM Module

1. deploying one kernel module via a single Module (module name is specified in the spec)
2. deploying multiple kernel modules, in case there is a symbols dependency between modules (as defined by module.dep). In this case the main module is specified in the Module, and running modprobe command on with that specific module will load all other modules that defines dependency for the main module

In case customer want to deploy multiple, independent kernel modules via single Module, the following sequence needs to be defined:

1. create /etc/modprobe.d/softdep.conf file inside ModuleLoader image

2. define dependency between kernel modules in the /etc/modprobe.d/softdep.conf file.
   Example: if customer has 3 modules in the image (simple-a, simple-b, simple-c) then the following definitions in the softdep.conf file will set the order of loading:

   softdep simple-a pre: simple-b
   softdep simple-b pre: simple-c
   

The order of loading will be: simple-c , then simple-b, then simple-a
The order of unloading will be reversed: simple-a , then simple-b, then simple-c

[ybettan]

Maybe we can ease on the user by adding a ConfigMap entry to the API (as we are doing for dockerfile) in order to add this dependency file.

Then all we need to do is to write that file to the container's FS at /etc/modprobe.d/softdep.conf.

[yevgeny-shnaidman]

i don't see bug difference between creating ConfigMap with a specific format, and asking user to add the file with that specific format to DriverContainer image. But maybe we can add a field to the ModuleLoaderContainerSpec where user will define the order in simple terms, and then we will translate it into softdep.conf format, and use your idea with ConfigMap to insert it into ModuleLoader image. That way we hide implementation, and can change it if needed.
And it will also help in case we need to use in-cluster build