KVM - The Linux Kernel-Based Virtual Machine
News, Blogs and Resources on the Linux (KVM) Kernel-Based Virtual Machine
Is ther any Recommendation for Kernel Config As VM Server (host)?
March 2, 2010 - 6:12am
hi,
I want to compile kernel and use him as server(host) of virtual machines..
Is there any Recommendation for Kernel Config?
Is there any Special Configuration(or Recommendation) for kernel to be used as Server?
My Target Machines are HP with Xeon Processors ...
My Distro CentOS (I'm using kernel rpm source)
best regards ...
There doesn't seem to be anything too specific about the hypervisor kernel other than maybe having the ability to select different schedulers, or maybe jumbo frames if you are serving guest disks via a SAN. Eg:
schedulers
-----------
CONFIG_IOSCHED_DEADLINE=y
CONFIG_IOSCHED_CFQ=y
CONFIG_DEFAULT_IOSCHED="cfq"
for iscsi (san)
-----------
CONFIG_SCSI_ISCSI_ATTRS=y
CONFIG_ISCSI_TCP=y
CONFIG_SCSI_QLA_ISCSI=y
I've been running about 10 linux guests on ubuntu 2.6.28-16-generic SMP for a few months and from
the hypervisor standpoint, it seems pretty solid.
The *guest* kernels on the other hand are much more peculiar in the way they interact with the hypervisor. If you are running on and x86_64 hypervisor, I would recommend sticking with x86_64 guests. I don't know why, but in my experience trying to run an i386 guest on x86_64 hypervisor causes a lot of weird problems. Random lockups, boot failures, network interface drops out; as soon as I switch to an x86_64 guest distro, things act much differently.
Different distros with different kernel versions will act differently too. I was running ubuntu 9.04 as a guest
for a few months and when karmic came out, I did a dist-upgrade and the guest was terribly unstable. I've recompiled a monolithic 2.6.28-10 kernel to copy to all the guests which seems to work way better than the karmic 2.6.31 flavor.
Knoppix 5.1 (not sure on kernel version) on the other hand runs flawlessly and is quite snappy as a guest. It's also a distro which is a number of years old.
Centos 5.x i386 will absolutely not boot on my setup (qemu-kvm-0.11.0). I have to run the x86_64 distro. No mix of kernel boot params will get the 5.x distro to boot. It always hangs at "ENABLING IO-APIC IRQs..".
Good luck
Hi,
Thanks for this good note ..
change of cpu frequency in kernel config to 100, was useful for me(to use linux as server).
Thanks again
I have been using KVM under Fedora 9/10/11 and Centos 5.4. My inclination now is to go 100% with Centos 64-bit due to the continual updates from the "upstream vendor". For example, Centos 5.4 has KSM (and 5.5 to have hugetlbfs) while my Fedora 9/10/11 installs do not unless I compile my own kernels.
And yes, stick with 64-bit guest distros.
Post new comment