restart a service on esx host with powershell without know the password

connect to vcenter:
connect-viserver [hostname of vcenter or IP of vcenter server]

connect to host:
get-vmhost [hostname or IP of esx server]

check status of services on Host:
Get-VmHostService [hostname or IP of esx server]

Restart ntp service:
Get-VmHostService -VMHost [hostname or IP of esx server] | Where-Object {$_.key -eq “ntpd”} | Stop-VMHostService
Get-VmHostService -VMHost [hostname or IP of esx server] | Where-Object {$_.key -eq “ntpd”} | Start-VMHostService

 

setup ntp on vcenter vsphere 4.0 (esx)

Click on each host, tab configuration> Time Configuration> properties