Garen's questions

I'm working inside a domain environment, served by Active Directory from a Windows 2008 host. I'm a regular "Domain User", with no special privileges and will not be able to get any.

When trying to setup my own Linux system to login via ssh with kerberos, I've run into a snag: I can't add a principal of the form: host/@DOMAIN

Which brings me to the question: is there any way around this to get single-sign-on (SSO) functionality?

If not, is there some other mechanism to accomplish SSO? (I'm guessing this would require setting up my own internal KDC).

Where I work, we are in need of upgrading our ClearCase servers and it's been proposed that we move them into a new (yet-to-be-deployed) VMmare system.

In the past I've not noticed a significant problem with performance with most applications when running in VMs, but given that ClearCase "speed" (i.e. dynamic-view response times) is so latency sensitive I am concerned that this will not be a good idea.

VMWare has numerous white-papers detailing performance related issues based on network traffic patterns that re-inforces my hypothesis, but nothing particularly concrete for this particular use case that I can see.

What I can find are various forum posts online, but which are somewhat dated, e.g.:

ClearCase clients are supported on VMWare, but not for performance issues. I would never put a production server on VM. It will work but will be slower. The more complex the slower it gets. accessing or building from a local snapshot view will be the fastest, building in a remote VM stored dynamic view using clearmake will be painful..... VMWare is best used for test environments

(via http://www.cmcrossroads.com/forums?func=view&catid=31&id=44094&limit=10&start=10)

and:

VMware + ClearCase = works but SLUGGISH!!!!!! (windows)(not for production environment) My company tried to mandate that all new apps or app upgrades needed to be on/moved VMware instances. The VMware instance could not handle the demands of ClearCase. (come to find out that I was sharing a box with a database server)

Will you know what else would be on that box besides ClearCase?

Karl (via http://www.cmcrossroads.com/forums?func=view&id=44094&catid=31)

and:

... are still finding we can't get the performance using dynamic views to below 2.5 times that of a physical machine. Interestingly, speaking to a few people with much VMWare experience and indeed from running builds, we are finding that typically, VMWare doesn't take that much longer for most applications and about 10-20% longer has been quoted.

(via http://www.cmcrossroads.com/forums?func=view&catid=31&id=44094&limit=10&start=10)

Which brings me to the more direct question: Does anyone have any more recent experience with ClearCase servers on VMware (if not any specific, relevant performance advice)?

At work we have Linux users who understandably prefer using Ubuntu. Problem is, we also have developer tools that only work with 'officially' supported Linux distributions that use much older 2.6.18 based kernels. (And even if they worked with newer ones, the vendors could always say they won't "support" the software unless it's on one of their 'officially' supported platforms.)

We could of course just tell them to use CentOS or something else 2.6.18-based, and I'm sure their response would be something like: "you can take Ubuntu from our cold, dead hands." :)

Which brings to me some questions--is there any good/easy/recommended way to run something like Ubuntu as a host VM and Centos 5.x as a guest OS (with which system--Xen,KVM,VMWare, ...?), and then roll that into our own custom internal distribution that could be easily installed?

KVM looks like a good high-performance option just recently included in RHEL 5.4, but if hardware support for virtualization like Intel-VT or AMD-V is necessary, then I'd guess only those folks with fairly new PCs will be able to do it.

Would be very interested to hear how anyone else has addressed this kind issue.

EDIT: The target audience / users of this kind of system would be developers, each one needs to run locally licensed commercial software, so building out some separate beefy central machines isn't an option unfortunately due to license restrictions. Even if that weren't the case, a couple developers could quickly eat up the resources with parallel builds. :)

Ideally, I was hoping there was some step-by-step guide out there to build your own pre-built distribution that had e.g. CentOS 5.x and Ubuntu Desktop as a guest.