rename ESX host

To rename a VMware ESX host:
*If the ESX host is part of a Cluster, remove it from the cluster.
*If the ESX host is managed by VirtualCenter / vCenter, disconnect and remove the ESX host from the cluster.
*Make the modifications in your DNS environment to reflect the correct name and IP association for the new name.
*Log in as root to the console of ESX host.
*Using a text editor (I prefer nano ) change the name and domain name, if applicable, of the host in these files:


nano /etc/hosts
nano /etc/sysconfig/network


Execute this command where hostname is the new FQDN hostname for the ESX host:

esxcfg-advcfg -s hostname /Misc/HostName

Reboot the ESX host.
Note:
The iSCSI Qualified Name used for iSCSI storage configuration is based on the hostname of the ESX host. If you change the hostname of the ESX host, make sure to review your iSCSI software initiator configuration
Join the ESX host to VirtualCenter / vCenter and clusters

reference:
http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1010821