Category Archives: vSphere PowerCLI

An adventure in Powershell and the vSphere PowerCLI

I’ve always found a good way to get started with a new language is to just go head into it trying to solve some problem you’re working on, then ask the Internet via a search engine how to do something you want to do.

Today I started for the first time with PowerShell. Here’s the problem I was trying to solve:

I have a lot of VMs that I want to bring up for a class that I’m giving. There could be between 10-50 people at any given class. What I need to do is clone a master VM from a template, change its MAC address to something I have reserved in my DHCP server, and then power it up.

All of this can be done via vCenter.  But its a slow and painful point-and-click-yourself-to-death process. Automation is the way to get this done.

All of this can be done via xCAT.  But I figured why not give it a try.  Other people can live without xCAT.  Maybe I can too.

I have a history of perl. Yes, I have lots of skeletons in the closet with that language. So I was going to do all of this with Perl. But I figured that since I was going to be doing power shell scripts anyway for the UCS emulator portion, why not just do it all with the same thing? So I gave it a shot.

First off, the Windows editors suck. I had to stick with VIM because there’s nothing better for me. Let’s not even argue about that. +1 for me for retaining my dignity.

Next, after installing the VMware PowerCLI tool it was pretty easy.

CreateVMs.ps1

Here’s the script to clone 9 VMS from a template called UCSPEMaster.  I just change it depending on how many I need.

Notice that each machine will be called UCSPEXX, where XX is the range I specify. That way if
4 more people walk into the class after I’ve configured 14, then I can do 15..8.

I also put all of them on the same host (192.168.1.4), the same datastore (datastore1), the same Folder (UCS Emulators), and made them thin clones.

If you have a cluster running Storage DRS (vSphere 5.0+) then you don’t have to specify the datastore and DRS will put it where it sees fit.

ConfigVMs.ps1

The only thing I need to do now is change the MAC address to something that I have reserved.  That way, I can tell the user to just log into the IP address that I’ve set up beforehand.  I’ve configured 60 IP addresses so that I’m ready for a big class.

Most of the script is made up of getting the last number part of the VM name. Since each VM is named UCSPE01-UCSPE60 then it grabs the 60, converts it to hex, then adds that as the last part of the MAC address of the adapter. This will work as long as I don’t have more than 255 VMs.

I could have put a Start-VM on the end of this.  Generally, that’s just a powershell one-liner:

removeVMs.ps1

The last script will just remove these VMs.  As I tweak around with them, or as people in the class tweak around with them, I just want to erase them and start fresh for the next class.  This is fairly easy:

The only thing I need to update this with is to not power it off if it isn’t on.  It throws some nasty errors if it’s not powered on.  But I’ll do that some other time.

I’ll get this lab working with PowerShell.  It’s not a bad language.  It’s another tool in the handbag.  I still prefer command line scripting with Bash or Perl.  But every now and then its fun to go over and see how the other side lives.  Now, back to xCAT.