SymptomsIn some cases cman service may fail to start on Parallels Virtuozzo Containers for Linux members:
[root@cluster ~]# /etc/init.d/cman start
Loading modules... failed
FATAL: Module lock_dlm not found.
CauseBy default cman tries to load module lock_dlm whereas already loaded modules dlm and lockd provide its functionality.
Usually, vzkernel-install package corrects cman startup script to make it working with Parallels Virtuozzo Kernel, but if cman was installed later the sequence would be broken and the above issue would be observed.
ResolutionRe-install vzkernel-install package from full Parallels Containers distribution with --force flag:
rpm -Uvh --force vzkernel-install-4.7.0-8rh.x86_64.rpm