You can disconnect and reconnect a host that a vCenter Server system manages. Disconnecting a managed host does not remove it from vCenter Server, but temporarily suspends all monitoring activities that vCenter Server performs.
The managed host and its associated virtual machines remain in the vCenter Server inventory. By contrast, removing a managed host from vCenter Server deletes the managed host and all its associated virtual machines from the vCenter Server inventory.
If an ESXi host becomes disconnected due to a loss of network connectivity to vCenter Server, the ESXi host reconnects automatically to vCenter Server after network connectivity is restored. If you manually disconnect an ESXi host, see Reconnect a Managed Host for more information.
Reconnecting an ESXi host automatically or manually does not impact the running virtual machines, unless the host is part of a cluster and there are resource pool privileges configured.