How to schedule shutdown of ESXi from Virtual Machine?

Andrej Pirman
Andrej Pirman used Ask the Experts™

my customer wanted some additional functionality, but was not compatible with Windows Server 2008, so I reconfigured the existing server, installed ESXi on it, and put back existing Windows 2008 server and additional Windows Server 2003.

Now, the problem is what to do with UPS automatic shutdown, which was fully functional on previous installation of Windows Server 2008? I have ESXi now, and things got complicated.

I might try to put thru the UPS signal, either via COM port, or via USB port, depending on what will ESXi let thru directly to Virtual Machine.
Then I would use UPS software on Windows 2008 server to shutdown this Virtual Machine, and configured the second VM (server 2003) in ESXi to shutdown too, when first machine shuts down. This is possible with ESXi.

But what about host ESXi? How could I shutdown host machine?
Couldn't I have some script, which would watch  - let's say - guest's RAM usage and shutdown host ESXi when guest RAM usage is 0? Or something like this.

There was a discussion on the same subject;jsessionid=49C105BC09DFAA3F0B28925A99EA62AC which ended with conclusion to just shutdown guest OS when power outage, and let host ESXi die.

But my question is:
any idea how to go one step further and shutdown also host ESXi with some script?
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I'm not sure and I've not tried but I think you can do something like that :

# In case of a serial or usb UPS connector

a) You need a esx host and 1 physical machine
b) Connect the esx host and physical machine to the usp
c) Connect the physical machine (not the esx host) to the usb or serial of the ups
d) Install the UPS software on the physical
e) Install the remote CLI on the physical
f) Use remote CLI script to start ESXi shutdown

 # In case of network connection to UPS

a) Only the esx host is needed
b) Install a virtual machine with UPS network software
c) Configure this vm to start at ESXi startup
d) Install the remote CLI on the vm
e) Use remote CLI script to start ESXi shutdown

Hope this can help you,
Giovanni Coa


Giovani, thanx for your input.

Your theory is by my oppinion good, except the last step, which I was already wondering about: "remote CLI script to shutdown ESXi".
ESXi does not, in contrary to ESX, support host scripting, so I actually do not know how to communicate with host ESXi from guest OS.
with the use of remote CLI installed on the guest (physical or virtual), you are able to send vmware commands throught network to the ESXi server (you need to specify the vmware server on the command line).

You can find how to download and install it on this link:,289483,sid179_gci1306901,00.html

I'm not sure that you can shutdown entirely the host server but surely you can shutdown the virtual machines.

You can also (I've not tested) enable SSH access to ESXi.
Try follow these steps:

Hope this can help you,
Giovanni Coa
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Have you tried to automatically shutdown every vmware machines throught CLI ?

Giovanni Coa


I am currently solving problem on how to pass-thru COM port communication from UPS to VM, for VM to be able to shut down all other VM's.
Have you used a LAN2COM device ?

Giovanni Coa


No Giovanni,
not yet. My UPS is connected to COM port, but I did not manage to pass-thru COM port to Virtual Machine. Is there any option to do that in ESXi? Or is it reserved only for ESX?

If there won't be any other option, I'll buy a SMTP card for my UPS and additional NIC adapter for ESXi, so one of VM's will have UPS connected directly via NIC LAN adapter and will be able to shut down properly all other machines.
I've used COM port in the past with ESX server and some times there a lot of issue in communicating, but I've not troubleshooted them in deep.

Have you choosen how to startup your virtual machines after the power outage ?

Hope this can help you,
Giovanni Coa


Hi Giovanni, thanx for info.

I decided to go parallel way, which means to install another physical machine with Windows XP parallel to ESXi machine, so I will have controll over ESXi all the time.
This XP machine will have central UPS console installed, with UPS clients on virtual machines, so it will be able to shutdown all virtual machines.
The only thing to find out is how to power off the host ESXi after virtual machines are shutdown....or even better, how to send power down command to ESXi, which would then nicely shutdown first all virtual machines, and finally ESXi itself. That would be the best sollution, even for power up.

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