Registration of a RHEV host failed with "Failed to initialize storage" error.

Issue

Registration of a RHEL host failed in a RHEV 3.1 environment with the following error reported in the engine.log file;

2012-12-20 07:20:23,504 ERROR [org.ovirt.engine.core.vdsbroker.VDSCommandBase] (QuartzScheduler_Worker-37) Command GetCapabilitiesVDS execution failed. Error: VDSRecoveringException: Failed to initialize storage
2012-12-20 07:20:23,508 WARN  [org.ovirt.engine.core.vdsbroker.VdsManager] (QuartzScheduler_Worker-37) ResourceManager::refreshVdsRunTimeInfo::Failed to refresh VDS , vds = dc679130-4ab7-11e2-be31-005056b20037 : hlxtil25, error = Failed to initialize storage, continuing.

The vdsm.log on the host contained the following sequence;

MainThread::INFO::2012-12-20 07:18:33,933::vdsm::70::vds::(run) I am the actual vdsm 4.9-44.1
MainThread::DEBUG::2012-12-20 07:18:34,524::resourceManager::379::ResourceManager::(registerNamespace) Registering namespace 'Storage'
MainThread::DEBUG::2012-12-20 07:18:34,525::threadPool::45::Misc.ThreadPool::(__init__) Enter - numThreads: 10.0, waitTimeout: 3, maxTasks: 500.0
MainThread::WARNING::2012-12-20 07:18:34,534::fileUtils::181::fileUtils::(createdir) Dir /rhev/data-center/mnt already exists
MainThread::DEBUG::2012-12-20 07:18:34,581::multipath::111::Storage.Multipath::(isEnabled) multipath Defaulting to False
MainThread::DEBUG::2012-12-20 07:18:34,582::__init__::1164::Storage.Misc.excCmd::(_log) '/usr/bin/sudo -n /bin/cp /tmp/tmpKXPFYw /etc/multipath.conf' (cwd None)
MainThread::DEBUG::2012-12-20 07:18:34,664::__init__::1164::Storage.Misc.excCmd::(_log) FAILED: <err> = 'sudo: sorry, a password is required to run sudo\n'; <rc> = 1
MainThread::ERROR::2012-12-20 07:18:34,665::clientIF::175::vds::(_initIRS) Error initializing IRS
Traceback (most recent call last):
  File "/usr/share/vdsm/clientIF.py", line 173, in _initIRS
    self.irs = Dispatcher(HSM())
  File "/usr/share/vdsm/storage/hsm.py", line 333, in __init__
    multipath.setupMultipath()
  File "/usr/share/vdsm/storage/multipath.py", line 127, in setupMultipath
    raise se.MultipathSetupError()
MultipathSetupError: Failed to setup multipath: ()
MainThread::DEBUG::2012-12-20 07:18:34,904::__init__::1164::Storage.Misc.excCmd::(_log) '/usr/bin/pgrep -xf ksmd' (cwd None)
MainThread::DEBUG::2012-12-20 07:18:34,935::__init__::1164::Storage.Misc.excCmd::(_log) SUCCESS: <err> = ''; <rc> = 0
MainThread::INFO::2012-12-20 07:18:34,935::ksm::40::vds::(__init__) starting ksm monitor thread, ksm pid is 99
KsmMonitor::DEBUG::2012-12-20 07:18:34,936::__init__::1164::Storage.Misc.excCmd::(_log) '/usr/bin/sudo -n /sbin/service ksmtuned start' (cwd None)
MainThread::INFO::2012-12-20 07:18:34,937::vmChannels::139::vds::(settimeout) Setting channels' timeout to 30 seconds.
VM Channels Listener::INFO::2012-12-20 07:18:34,942::vmChannels::127::vds::(run) Starting VM channels listener thread.
KsmMonitor::DEBUG::2012-12-20 07:18:34,961::__init__::1164::Storage.Misc.excCmd::(_log) FAILED: <err> = 'sudo: sorry, a password is required to run sudo\n'; <rc> = 1
KsmMonitor::DEBUG::2012-12-20 07:18:34,962::__init__::1164::Storage.Misc.excCmd::(_log) '/usr/bin/sudo -n /sbin/service ksm start' (cwd None)
KsmMonitor::DEBUG::2012-12-20 07:18:34,987::__init__::1164::Storage.Misc.excCmd::(_log) FAILED: <err> = 'sudo: sorry, a password is required to run sudo\n'; <rc> = 1