Frequently Asked Questions
Which kernel options should I enable/disable ?
Once your kernel is patched, you can run make defconfig in kernel sources dir to generate a default configuration which is known to work. Kerrighed relative options are in Cluster support section. Disabled one, by default, are usually experimental.
Unfortunately, we can not test Kerrighed with all combination of Linux configurations. Nevertheless, the following options are known to be *broken* with Kerrighed:
Can I use Kerrighed with any version of Linux ?
No. Kerrighed is made of a patch to the Linux kernel plus some other tools. Hence it is designed on a particular version of a Linux kernel. You can find the Linux version to use the installation manual for each Kerrighed version.
Does Kerrighed support thread migration?
No. This feature was disabled early in the port from Linux 2.4.x to Linux 2.6.11. It should come back in the future. Please read this post for more details.
How do I know if the cluster is running? (aka How can I check that krgadm cluster start succeeded?)
krgadm fails with segmentation fault
This is a known bug of krgadm in Kerrighed 2.3.0 and earlier. This is fixed in trunk and later versions.
krgadm cluster status tells me that no cluster is running, but krgadm cluster start seemed to work
krgadm cluster status is buggy in Kerrighed 2.3.0 and earlier. This is fixed in trunk and later versions.
My processes do not migrate!
Four main issues:
Otherwise some processes won't migrate because they use a currently unsupported feature (eg POSIX timers), or some of their cluster-wide resources (eg NFS files) could not be found on the target node.
My process does not fork remotely
My process cannot use remote memory
Where are my keys ?
I don't know.