Hi Shravan,
Thank you for catching this documentation discrepancy.
- Is this intentional or a miss?
It's a mistake which will be fixed. The Singleton and Custom Plug-in Topologies section is still applicable in 7.0U1.
- Does VMware support a singleton plugin topology (single plugin instance registering to multiple vCenters in ELM) in future releases?
Yes. It is supported. Please check the doc section mentioned above.
- Does VMware have any recommendation like each vCenter server should have its own plugin instance (1:1 mapping)?
Each vCenter Server can have only 1 plugin instance serving the plugin UI but each instance can be registered with multiple vCenters as discussed above.
For other non-UI purposes you can also add auxiliary servers together with the same plugin instance registration with a vCenter.
Cheers,
Vladi