When in Console (Web or Desktop), attached to ESM I can select a host but can't run "Rediscover" on that host because it is grayed out!
The behavior is per design. HOSTs are not supposed to be able to be individually rediscovered from ESM. They should be discovered/Re-discovered from IP and following an automatic Topo Synch , ESM is updated with any changes.
When a HOST is rediscovered from IP, the dxa will be triggered and then followed by ESM discovering the device. This design approach is to ensure data consistency, e.g., a complete rediscovery of the device would have to start from IP.
HOST Rediscover in ESM alone may risk bringing in a partial update of the device.