From the NSX Manager central CLI, you can check the health status of each ESXi host.

The health status is reported as critical, unhealthy, or healthy.

For example:

nsxmgr> show host host-30 health-status
status: HEALTHY

nsxmgr> show host host-29 health-status
UNHEALTHY, Standard Switch vSwitch1 has no uplinks.
UNHEALTHY, Storage volume datastore1 has no enough free spaces: 19.% free.
status: UNHEALTHY

nsxmgr> show host host-28 health-status
CRITICAL, VXLAN VDS vds-site-a VNI 200000 multicast addr is not synchronized with VSM: 0.0.0.0.
CRITICAL, VXLAN VDS vds-site-a VNI 200003 multicast addr is not synchronized with VSM: 0.0.0.0.
CRITICAL, VXLAN VDS vds-site-a VNI 5000 multicast addr is not synchronized with VSM: 0.0.0.0.
Status: CRITICAL

The host-check command can also be invoked through the NSX Manager API.