IBM will be bringing KVM Linux virtualization to Power in 2014 | Hacker News Reader

IBM will be bringing KVM Linux virtualization to Power in 2014

zdnet.com

21 pointsrbanffy17 comments

Power has LPARs, so why bother?

If I use Linux on Power by choice, I'm either doing OLAP/OLTP or I'm an AIX shop that needs a few Linux boxes without the hassle of a completely different platform (x86) in the mix.

But I can't imagine anyone wants to use IBM Power to host a large number of Linux KVM VMs, that just doesn't make sense.

It depends how large you are. Managing physical boxes in a datacenter can be very expensive. Being able to virtualize on any platform is a good thing, as you can decide your own balance of costs between physical space, energy, network gear, network people, operations. These physical costs are often overlooked when you're talking about hardware. It takes a lot of $ to operate your own data center.

I have a better "Why?":

KVM is handy because you can run an unmodified guest. There are many reasons why somebody would like that, for example to run the latest greatest product somebody ships as an ISO (or VM) image.

If I understood correctly, KVM on POWER would allow to run unmodified OS guests built for the POWER architecture.

What's the use case? Where are the tons of pre existing but subtly different distributions you want to run together but have nobody supporting a couple of small fixes to let it run in a paravirtualized environment.

I'm genuinely curious about the usual ecosystem that people who run linux on IBM POWER have to cope with.

This is a case where Power differs from x86. Before KVM, PowerVM was mandatory on Power so every OS ran in a VM and these VMs were all paravirtualized. So "unmodified" Power OSes are already PV.

Hence I don't understand what's the point of KVM for the POWER platform. Could you shed some light?

Why?

POWER is really nice. I mean properly awesome, but no one seems to use it these days. Even our ex-AIX financial orgs have gone x64 and a lot to windows...

I often think of the IBM Power platform as the "Dark Matter" of computing - nobody we know has ever seen, or used such a system, but it occupies huge amounts of budgets for computing.

We were joint bidding a $Billion+ project with IBM in 2004/2005, and they lent us a handful of P5 520s to do some initial development on. They were bizarre systems, and just trying to get your standard C packages to compile under AIX was a painful chore for someone used to the portability on Solaris/Linux/BSD back then. Heck, even Irix was easier.

Happy to hear that there is more weight going into KVM, I almost thought that platform had died under the Tsunami of VMware and Xen (Amazon). Nice to know there will be some real competition.

Bizarre it is, at least to someone who is used to a modern environment. I once hat a gig setting up a open source softare stack on AIX, it was very painful to do. AIX admins aren't really helpful either because their knowledge is really domain specific and everything they usually run is well documented / supported by IBM.

For anything open source related on AIX, http://www.perzl.org/aix/ is a lifesaver.

But, the hardware just scales brutally. You can add/remove LUNs/CPUs/RAM from LPARs without interrupting operations. The Powers hosting the machines I worked on were basically bought, installed and switched on and are now up and running until they are decommissioned years later.

KVM is used, a lot: it is the backbone of Red Hat's virtualization in RHEL6. Also, if you create a new VM using Gnome Boxes, you will have a KVM VM unless you go out of your way.

Re: "KVM is used a lot" - Our company actually standardized on KVM about 7 years ago, and, then, after about three years of realizing we weren't facebook scale, spent the next couple years migrating everything to VMware.

Running your stack on KVM is like running your IPSec concentrators on OpenBSD (been there, done that) - it makes an awful lot of sense technically, particularly to the people who are actually using it every day - but, from the perspective of the enterprise - No Support ecosystem, No market presence, Poor compatibility testing. One of the best things ever for Linux in the enterprise was RHEL/SUSE and their corporate support for the platform.

I'm willing to wager 90%+ of the virtualization market in the fortune 500s is VMware, and KVM has next to zero market penetration.

I'm hoping that changes with the broad market support we're starting to see from IBM and the various open stack alliances.

Anyone using RHEL6's built-in virtualization technology is using KVM, it's just all wrapped up in libvirt stuff. Those tools were in early development 7 years ago.

IBM uses it. I think that alone is enough for them to invest in it.

The article says "Unfortunately, KVM only works on Intel and AMD processors"; actually it works also on S390, Power and ARM, though different archs are at different places in the "initial prototype" to "production ready" spectrum. I think what they're actually talking about here is the fact that IBM are ready to ship it as a supported product and get distros to do so too.

Who actually use IBM's Power these days? And SPARC? I see ARM, AMD and Intel only.

I do :)

Why do you guys [I assume Bloomberg] use POWERS or SPARC?

Probably like any of their other customers, there is a framework which was developed that runs on big-endian hardware and the development cost to certify (read: not the porting work) that calculations are correct if switched to x86 is not necessarily worth it as long as the machines follow Moore's law just like any other hardware.

These machines represent a tiny tiny portion of overall machines, but have certain properties that make them nice for certain functions. They can handle a lot of I/O and can reduce software complexity for certain jobs which actually don't need to scale horizontally.

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