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Hybrid kernel for CloudLinux 5 -- First beta

I am happy to introduce ability to run 2.6.32 kernel from CloudLinux 6 on CloudLinux 5 servers.
The 2.6.32 kernel is a major improvement representing more then 5 years of development. It is generally faster & more stable then 2.6.18 kernel shipped with CloudLinux 5.

To install the kernel on your CloudLinux 5 server, please run:
# yum update rhn-setup --enablerepo=cloudlinux-updates-testing
# /usr/sbin/normal-to-hybrid
# reboot

To convert back to original CloudLinux 5 server:
# /usr/sbin/hybrid-to-normal
# reboot

Please, note following limitations & changes regarding CloudLinux 6 kernel/Hybrid kernel:
  • Hybrid kernel doesn't correctly recognize xvda devices (using sda instead) on Xen PV installations, causing kernel panik on boot
  • There is an issue with systems with CageFS 2 installed, please refrain from installing on such servers until second beta.
  • CageFS 3 beta is not available yet with this kernel (should become available next week)
  • Load averages are calculated the way they are calculated int CentOS. This means that if one site is getting limited, it will cause limits to increase, even if there is no increase in actual CPU usage, and server is not overloaded
  • Memory limits are enabled by default, there is no ubc setting, and you cannot do lvectl ubc disable. To disable memory limits, set them to 0
  • There is no separate kernel-xen, instead regular kernel package will be installed. That package will satisfy xen requirements, and supports para-virtualization

01/21/2012 04:30:22
Will this hybrid kernel stop all the hundreds of migration processes we have currently shown in "top" ?
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Igor Seletskiy
01/23/2012 14:57:18
Yes, it would -- it has different architecture all together. In lve0.8.54 kernel for CL5 the migration threads are still there, but they are well hidden.
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