When you want to use CEPH as the backend of Openstack, you may face this error in ceph admin while MAP your newly created volume.

    ERROR: modinfo: could not find module rbd
    FATAL: Module rbd not found.
    rbd: modprobe rbd failed! (256)

This is because RBD module is not loaded in the Kernel. I have searched a lot in internet on how to enable RBD module in the Kernel. I am summarise my finding here.



CURRENT SYSTEM

COMPONENT      CINDER

OPENSTACK        ICEHOUSE

OS                       CENTOS 6.6

KERNEL              3.18.0 (64)

I had updated kernel to the latest build using the following way.

#rpm --import http://elrepo.org/RPM-GPG-KEY-elrepo.org
#rpm -Uvh http://elrepo.org/elrepo-release-6-5.el6.elrepo.noarch.rpm
#yum --enablerepo=elrepo-kernel install kernel-ml # will install 3.11.latest, stable, mainline

After finishing the installation, change the default boot kernel to newly installed one

#vim /etc/grub.cfg

Change the following 1 TO 0

default=0

Reboot the system, now you will have new kernel with 3.18.1-1

#uname -r

3.18.1-1

Try to search for RBD Module.

[root@cinder ~]# lsmod | grep rbd
rbd                    57971  0
libceph               166955  1 rbd
[root@cinder ~]#