split default overlays into discrete functionality

[anderbubble]

Summary

Split the generic and wwinit overlays into multiple discrete overlays based on their functionality. For example, wwinit might be split into NetworkManager, ifcfg, udev, etc.

These overlays should then be explicitly included by the default profile (not implicitly included by a built-in setting).

Rationale

The monolithic overlays make it difficult to opt-out of discrete parts of built-in Warewulf functionality.

Description

No response

Additional information

No response

General information

• I have searched the issues of this repo and believe this is not a duplicate

[blixuga]

Assuming that #885 is going to be a prerequisite for this?

[anderbubble]

Assuming that #885 is going to be a prerequisite for this?

Not specifically, though #885 will probably be merged in first anyway. (I just haven't gotten to it.)

[griznog]

I've been thinking about this quite a bit, encouraged my my ongoing experiment of multiple clusters/sites sharing a base set of overlays and today @anderbubble 's comment in #1208 sparked an idea. I'm now thinking:

• Warewulf distributed overlays go into /usr/share/warewulf/overlays.
• User defined overlays and modifications go into /etc/warewulf/overlays.
• A user overlay of the same name as a Warewulf Overlay overrides the warewulf overlay file-by-file during overlay building.

Under this arrangement if I only want to modify one file in the upstream overlay ANOVERLAY, I'd create /etc/warewulf/overlays/ANOVERLAY and put only my modifications in there, leaving the rpm-delivered overlay untouched. Locally defined overlays just need to not conflict with names of warewulf provided overlays, which could be addressed by prefix/suffix on warewulf provided overlay names.

I think this would allow easy locally managed revision control for /etc/warewulf/overlays with just modifications to standard overlays and custom local overlays in this location. rpm/dpkg updates could optionally run a script to warn if an updated file is also present in the local overlay location. Bonus of this rolling overlays into any revision control already in use in /etc/warewulf.

griznog

[anderbubble]

I 100% agree with @griznog.