Easy ESXi 4.1 with serial or USB UPS control

In the past, there has always been a problem with setting up USB uninterruptible power supply to VMware ESXi servers.  Here is the method of enabling a VMware ESXi 4.1 bare-metal server to communicate with an inexpensive serial or USB-only UPS system.

Install a Guest Windows System

You will need to install a Windows virtual machine to run the power management software, and connect to the UPS system.


I have used APC Powerchute software on a Windows 2008 server with this installation method, and encountered no problems.

Most Windows OS guests with USB management software should work in the same way.


Enabling the USB Pass-through  

Now that ESXi 4.1 has been released, it is possible to use a USB data cable on any UPS and communicate with Windows control software.  

ESXi 4.1 has the ability to make a USB connection from the server hardware, directly through to a virtual machine hosted on the same server.

This allows UPS monitoring software to run on a windows virtual machine on the server and talk to the UPS on the ESXi server USB hardware.

You will need to make sure the USB adapter is attached to only the power controller guest OS, to minimise other guest OS conflicts. 

The management and attachment of the USB hardware is done in the virtual machine hardware configuration screen.

When adding USB hardware to the hardware of the virtual machine, a new option is now available for direct USB hardware access.


Enabling the SSH Service for Root Access

The next step is to enable the SSH service on the ESXi server, so a root remote console is present via SSH.

You will need physical access to the ESXi server, so you can login to its console as the root user.

Edit the configuration file for SSH with the following command:

nano /etc/ssh/sshd_config

Find the line that starts with PermitRootLogin and change the "no" to "yes".
 
Restart the sshd service with the command:

service sshd restart

The SSH service will now accept root logins to the console for running scripts. 



Windows Guest Script File  

On the Windows virtual machine running the Powerchute software, a small .bat file needs to be created, pointing to a free SSH client called Putty.

You can download Putty from their website. http://www.chiark.greenend.org.uk/~sgtatham/putty/ 

After getting Putty and setting up the .bat script, log into the same directory on the Windows guest. 

You will be able to point your UPS control software directly to the shut-down script on the local host.

Windows .bat file:
-------------------------------------------------

putty "server-address" -l root -pw "password" -m Unix_Commands

-------------------------------------------------


Unix_Commands file:
-------------------------------------------------

poweroff

exit

-------------------------------------------------


Final Notes

This new feature for USB connections in ESXi 4.1 makes it very easy to implement UPS systems into the VMware environment. I have only tried this with Windows 2008, running APC Powerchute software and uninterruptible power supply with USB control. But I believe any configuration of Windows and power control software should work.

Redundant 48 Volt Power Supply - Part 2 - Wiring up the Rack and PSU

Now comes the all important job of wiring up the rack mounted power supply units.

This part of the project requires heaps of wire, a soldering iron, connectors and a steady hand.

Important WARNING - The next part is for informational and academic use only. This system uses dangerous and lethal voltages. Only qualified and experienced technicians should work on high voltage power supply systems.

Wire up all the internals with the appropriate cable types and colour coding. It is important to use the correct wire types and colours for the 240AVC and 48VDC circuits. All the wire ends were soldered onto connectors or terminals and all exposed connections covered in heat shrink tubing. Also, the yellow grounding cable to the rack casing was securely attached to the earthing connector on the case.

The PSU & rack all wired up

Below is a diagram showing the PSU wiring in the 2ru rack case. With 240VAC mains power coming into the PSU unit and the clean 48VDC power being delivered out of the unit. 

Parts list per PSU circuit:

1x 3700K Resistor 1x LED with mount 1x 240VAC fuse holder 1x IEC socket with mount

1x DC power socket with mount 1x Ceramic fast blow fuse 1x Switch (Suitable for 240VAC) Loads of wire for 240 volt and 48 volt Applications

Below are images of the front and back panels. On the front panel is mounted the power switch, red LED and DC power connector socket. On the back is the IEC power socket for the 240 volts AC cord connection and the fuse holder with a quick blow ceramic fuse.

Close-up of the front of the rack

Close-up of the back of the rack

Now the task remaining was to make up the DC power cables and test the PSU units before turning them on (I used my multimeter all the way though the building process, which is good practice).

Everything looked good and I was ready to test with mains power and a heavy load on the DC outputs.

DC Power Cables

Testing the PSU racks

Put the tops back on and plug them in.

Test the DC voltage and ensure everything is fine at 48.2 VDC. No leaks or other obvious problems.

All done, with two redundant 48 VDC power supplies ready to be shipped out. (I also had another technician check it over).

PSU all finished front view

PSU rack all finished back view

Stay tuned to Burning the Midnight for the next and final part of this project.

I will be mounting the rack unit and connecting up the redundant power supply to a Longreach X-Band wireless backhaul.

More fun and excitement.

Redundant 48 Volt Power Supply - Part 1 - Mounting and PSU

I have started construction of two redundant 48 VDC power supplies for use with large scale telecommunication equipment.

They will be powered by a 240VAC UPS with a diesel backup generator.

These two PSUs are for two X-Band Longreach Wireless backhauls (CarrierComm backhauls), which can transmit <300Mbps over 50km.

More about them later... 

First of all, I needed something to mount everything into. Preferably a 2RU rack mounting. Found the rack kits at Jaycar Online. Jaycar is a handy place with loads of equipment and parts, and I wish they paid me for this ad.

Rack Mounting from Jaycar

Rack and Rack Mounting Kit

Next I needed to find some power supplies to fit the rack units. I shopped around online and picked up two TDK-Lambda HWS15-150-48A caged PSUs from Digikey.

These units are quiet, cool and slim, while still producing 3.3 amps at 48 volts.

Top View of the hws15-150

Front View of the hws15-150

The kits was easy to build, with easy installable din rails. The front and back panels are simple to remove and replace for case work. Mounting PSUs was also straight forward, with a few small screw holes to mount the fames at the bottom.

Rack with the PSUs mounted

Close-up of the rack mounted PSU

Removed the front and back panels to work on in the lab.

I had to cut and drill some mount holes into the panels for the IEC power mounts, LEDs, fuses and switches.

Sparks and aluminium bits flew everywhere. The front 3mm aluminium panel was a challenge to work with.

After preparing the panels, I then gave them a fresh coat of black paint to remove any of the scratches. 24 hours later, the dry panels are ready for components to be mounted. Then I assembled the main rack case.

Finished Panels

Look on Burning the Midnight for the next part of this project.

I will be wiring up the rack mount and PSUs and publishing the wiring diagrams, pictures and comments as the unit comes together.

News Flash!
"Part 2 - Wiring up the Rack and PSU" on up and online, so check the next chapter..

Latest Projects and Upcoming Articles

Here's some of the new projects that I have been working on. A bit of a mixed bag at the moment, from PSUs and robotics to VMware.

The projects include: VMWare Infrastructure review and tricks. Redundant 48 volts power supply for telecoms equipment. Solar system reporting to computer intergration software. A tracked robot running on Linux and wireless networking.

Stay turned for these informative and useful project updates.

Further project information will be added to the new Burning the Midnight website.

Check it out at http://sites.google.com/site/burningthemidnightproject/