Support Parsing ZTP Script via per-switch Configmap

[hardikdr]

Proposed Changes

Add strict ConfigMap-based ZTP mode

Adds --ztp-mode:

• templates (default): existing leaf/spine template behavior
• configmap: serves the ZTP script from the ConfigMap referenced by the matching Switch.spec.ztp

ConfigMap mode matches the ZTP client source IP to spec.ztp.sourceAddress and never falls back to templates.

[peanball]

Is this feature to iterate quicker on ZTP script variants during development? I thought the point of us using templates was so we don't have to maintain individual ZTP scripts for each of the switches.

Going forward, we should also have fewer instructions in the ZTP, which should be uniform for all switches (install the agent, which does the rest), right?

[hardikdr]

Is this feature to iterate quicker on ZTP script variants during development?

Going forward, we should also have fewer instructions in the ZTP, which should be uniform for all switches (install the agent, which does the rest), right?

That's correct.

Agree, the idea is exactly what you have described. This PR is only an option to additionally be able to start the switch with custom ZTP(experimental/during dev) if required, without changing the template here.
We can discuss whether we need such a feature at all; otherwise, we can close this one. :)