Issue

• Previewing a snapshot fails and reports the following in the Events pane;

Failed to complete Snapshot-Preview <snapshot description> for VM <vm name>.

• Attempting to 'Undo' a snapshot preview fails and reports the following in the Events pane;

Failed to restore <vm name>

• A stateless VM may report the following error when it is started because the stateless snapshot was not removed when it was last shutdown;

Failed to start <vm name>, because exist snapshot for stateless state. Snapshot will be deleted.

• The /var/log/ovirt-engine/engine.log file contains;

2014-01-31 16:37:07,139 ERROR [org.ovirt.engine.core.bll.RestoreAllSnapshotsCommand] (http-/0.0.0.0:8443-6) [183475ec] Command org.ovirt.engine.core.bll.RestoreAllSnapshotsCommand throw exception: java.lang.NullPointerException
        at org.ovirt.engine.core.bll.snapshots.SnapshotsManager.removeDisksNotInSnapshot(SnapshotsManager.java:411) [engine-bll.jar:]
        at org.ovirt.engine.core.bll.snapshots.SnapshotsManager.synchronizeDisksFromSnapshot(SnapshotsManager.java:398) [engine-bll.jar:]
        at org.ovirt.engine.core.bll.snapshots.SnapshotsManager.attempToRestoreVmConfigurationFromSnapshot(SnapshotsManager.java:247) [engine-bll.jar:]
        at org.ovirt.engine.core.bll.RestoreAllSnapshotsCommand.restoreConfiguration(RestoreAllSnapshotsCommand.java:222) [engine-bll.jar:]
        at org.ovirt.engine.core.bll.RestoreAllSnapshotsCommand.restoreSnapshotAndRemoveObsoleteSnapshots(RestoreAllSnapshotsCommand.java:190) [engine-bll.jar:]
        at org.ovirt.engine.core.bll.RestoreAllSnapshotsCommand.executeVmCommand(RestoreAllSnapshotsCommand.java:94) [engine-bll.jar:]
        at org.ovirt.engine.core.bll.VmCommand.executeCommand(VmCommand.java:82) [engine-bll.jar:]
        ...... etc., etc, ......

or;

2014-01-30 09:10:56,514 ERROR [org.ovirt.engine.core.bll.EntityAsyncTask] (pool-4-thread-48) EntityAsyncTask::EndCommandAction [within thread]: EndAction for action type TryBackToAllSnapshotsOfVm threw an exception: javax.ejb.EJBException: java.lang.NullPointerException
        at org.jboss.as.ejb3.tx.CMTTxInterceptor.handleExceptionInNoTx(CMTTxInterceptor.java:191) [jboss-as-ejb3.jar:7.2.0.Final-redhat-8]
        at org.jboss.as.ejb3.tx.CMTTxInterceptor.invokeInNoTx(CMTTxInterceptor.java:237) [jboss-as-ejb3.jar:7.2.0.Final-redhat-8]
        at org.jboss.as.ejb3.tx.CMTTxInterceptor.supports(CMTTxInterceptor.java:374) [jboss-as-ejb3.jar:7.2.0.Final-redhat-8]
        at org.jboss.as.ejb3.tx.CMTTxInterceptor.processInvocation(CMTTxInterceptor.java:218) [jboss-as-ejb3.jar:7.2.0.Final-redhat-8]
        ...... etc., etc, ......
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471) [rt.jar:1.7.0_51]
        at java.util.concurrent.FutureTask.run(FutureTask.java:262) [rt.jar:1.7.0_51]
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) [rt.jar:1.7.0_51]
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) [rt.jar:1.7.0_51]
        at java.lang.Thread.run(Thread.java:744) [rt.jar:1.7.0_51]
Caused by: java.lang.NullPointerException
        at org.ovirt.engine.core.bll.snapshots.SnapshotsManager.removeDisksNotInSnapshot(SnapshotsManager.java:411) [engine-bll.jar:]
        at org.ovirt.engine.core.bll.snapshots.SnapshotsManager.synchronizeDisksFromSnapshot(SnapshotsManager.java:398) [engine-bll.jar:]
        at org.ovirt.engine.core.bll.snapshots.SnapshotsManager.attempToRestoreVmConfigurationFromSnapshot(SnapshotsManager.java:247) [engine-bll.jar:]
        at org.ovirt.engine.core.bll.TryBackToAllSnapshotsOfVmCommand.restoreVmConfigFromSnapshot(TryBackToAllSnapshotsOfVmCommand.java:103) [engine-bll.jar:]
        ...... etc., etc, ......