posted Dec 18, 2008, 10:16 AM by Philip Rinehart
updated Dec 18, 2008, 10:17 AM by Greg Neagle
|Written by Alex Schaefer |
|Monday, 12 March 2007|
|Alex Schaefer, University of Colorado has adapted the method of using shadow files for Classic to deploy Windows XP via Parallels in the labs at the University.|
"Here at the University of Colorado, I've been looking into
distributing and updating Parallels within our well established
Radmind setup that we have going. My first big concern was
radminding Parallels virtual hard drives every night - at 3 gigs in
size, I just don't like the load that could generate on the server.
I've also been very concerned with keeping the images sanitary -
Windows gets messy and the last thing I want our Mac group to do is
worry about keeping our Windows load-sets clean.
I have been messing with throwing the entire Parallels hard drive
image into a read-only DMG and then on login, having it mount
noverify/nobrowse with a Shadow File. The shadow file acts as a way
to keep our Windows load-set as clean as we possibly can - because
all writes are logged to a shadow file, on logout when the image is
unmounted and the shadow file deleted, the original windows image is
in the exact same condition as it was before the user touched it.
Also, should a user get some virus or spyware on the system that goes
right past the group policies, on logout it's all reset. The trick
becomes to just make a Windows load-set the right way before
deployment, and then after that the user's space is taken care of.
Thanks to the DMG being read only it won't trip FSDIFF during
Radmind, so it allows us to not have to Radmind every machine every
night unless we update the core VM hdd.
Now this does mean we're going to have to apply windows patches when
they're deployed, but the creation of a Shadow-Parallels setup isn't
too bad to do, and so running windows update once and then updating
the shadow distribution shouldn't be a hassle. We have also gotten
around having to worry about updating the Windows Load-set when we
want to add new programs by using Soft-grid to virtualize the loading
process to the VM's - so we can remotely add or remove programs to
run on these machines without actually downloading them (and what
parts we do have to download are shoved into a non-shadowed Parallels
VM hard drive that contains just cache for Soft-grid, and I believe
we'll be putting this into our Radmind negative file).
To create a shadow-file-parallels hd, use the following directions.
Before you start, make sure your copy of Parallels is not running and
that the VM is not suspended or paused or any some such nonsense -
Parallels cannot be running period.
* 1) Create a hybrid image of the .hdd
-First create a staging directory (here named "Parallels_XP_HDD"
that contains only the hard disk file in question. Other hard disk
files, or any files can be put in here, but they will be read only)
-Create the hybrid using hdiutil:
hdiutil makehybrid -hfs-volume-name Parallels_XP Parallels_XP_HDD/ -
* 2) Convert hybrid image (iso) to read-only DMG
hdiutil convert -format UDRO Tmp.dmg.iso -o Parallels_Loadset_XP.dmg
* 3) (Optional) delete the tmp file... its useless
* 4) You're done! Mount it w/ a shadow now!
hdiutil mount Parallels_Loadset_XP.dmg -shadow /Users/LabGuest/Shadow