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https://issues.apache.org/jira/browse/CLOUDSTACK-9796?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15876548#comment-15876548
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ASF GitHub Bot commented on CLOUDSTACK-9796:
--------------------------------------------
Github user nathanejohnson commented on a diff in the pull request:
https://github.com/apache/cloudstack/pull/1956#discussion_r102295771
--- Diff:
engine/orchestration/src/com/cloud/vm/VirtualMachineManagerImpl.java ---
@@ -744,14 +744,17 @@ protected boolean checkWorkItems(final VMInstanceVO
vm, final State state) throw
protected <T extends VMInstanceVO> boolean changeState(final T vm,
final Event event, final Long hostId, final ItWorkVO work, final Step step)
throws NoTransitionException {
// FIXME: We should do this better.
- final Step previousStep = work.getStep();
- _workDao.updateStep(work, step);
+ Step previousStep = null;
+ if (work != null) {
+ previousStep = work.getStep();
--- End diff --
Most of this code I didn't write, but I can make some guesses:
_workDao.updateStep(work, previousStep) line is in the finally block, which
will execute even if an exception is thrown in stateTransitTo (like
NoTransitException for instance). So if stateTransitTo a) returns a false, or
b) throw an exception, then result will be false, and line 758 will run. So if
something happens that the state isn't transitioned, someone wanted the work
reverted to its previous step value. Sort of a rollback maybe?
In the case of the VM hung in starting, my desired side effect is I want
stateTransitTo to be called and set the state to Stopped , i.e.,
Event.AgentReportStopped -> State.Stopped . The work has already expired at
this point, so it is null. I was trying to preserve the same behavior as
before when work was not null.
Sorry if this wasn't very clear.
> Null Pointer Exception in VirtualMachineManagerImpl.java
> --------------------------------------------------------
>
> Key: CLOUDSTACK-9796
> URL: https://issues.apache.org/jira/browse/CLOUDSTACK-9796
> Project: CloudStack
> Issue Type: Bug
> Security Level: Public(Anyone can view this level - this is the
> default.)
> Affects Versions: 4.8.0, 4.9.0
> Environment: Cloudstack 4.8
> Reporter: Nathan Johnson
> Assignee: Nathan Johnson
> Priority: Minor
> Attachments: npelog.txt
>
>
> When a situation occurs where a VM hangs in the "Starting" state for longer
> than the job.expire.minutes, and the job is deleted from the system, a null
> pointer exception will occur because the work VO will be null inside of
> advanceStop in VirtualMachineManagerImpl.java . I have attached a snippet of
> a log file of this NPE occurring in the wild.
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