Provision half a core as a virtual CPU

cloudvirtualizationxen

I am virtualization newbie. Please advise on these questions. Please note using a commercial VM software like Citrix or VMware is not a choice for me.

I have at my disposal a couple of 2x 4 core servers with 32 GB RAM. I need to create 16 VMs on each server to test some web applications.

  1. Can I provision half a core as a virtual CPU for each VM? To my best knowledge I can't do so on Xen. Is it possible on KVM or some other free open source VM solution?

  2. If it's not possible to assign half a core, how do I ensure that uniform processing power is available for all VMs?

  3. Since the job is to create separate instances for hosting 16 web apps in a physical server, do you recommend setting up a private cloud using Ubuntu Enterprise Cloud as a better option?

  4. Is there HA solution under KVM, like Remus for Xen?

Best Answer

  1. To the best of my knowledge, assigning half a vCPU isn't possible on KVM. It's certainly not using something like RHEV, which is based on KVM.

  2. Assign one vCPU to each machine. Since KVM uses the linux scheduler for distributing workload rather than actually assigning physical CPUs to VMs, this should work fine. We currently have more vCPUs than physical CPUs running on our hosts.

  3. UEC might be a simpler option than KVM, especially if you start to introduce a level of complexity like configurating HA for KVM. If you don't have much experience with KVM or linux, UEC is a viable option.

  4. It's possible to implement HA for KVM through libvirt, although this is something I haven't personally tried yet (we use RHEV which does it through a GUI). I would refer to http://www.linux-ha.org/doc/re-ra-VirtualDomain.html

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