| Message ID | 20200519190230.29519-2-ian.jackson@eu.citrix.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Upgrade most hosts/guests to buster | expand |
On Tue, May 19, 2020 at 3:03 PM Ian Jackson <ian.jackson@eu.citrix.com> wrote: > > This seems mostly to affect buster but it could in principle affect > earlier releases too I think. > > In principle it would be nice to fix this bug, and to have a proper > test for it, but a reliable test is hard and an unreliable one is not > useful. So I guess we are going to have this workaround > indefinitely... `xl shutdown -w` waits for either domain shutdown or destruction in wait_for_domain_deaths() https://github.com/xen-project/xen/blob/master/tools/xl/xl_vmcontrol.c#L183 My understanding is shutdown happens first when the guest stops and destruction happens afterward when all the resources are cleaned up. So your race is that the domain shutdown, but it still shows up in `xl list` since it hasn't been destroyed. OpenXT has a hack to only wait for destruction https://github.com/OpenXT/xenclient-oe/blob/master/recipes-extended/xen/files/xl-shutdown-wait-for-domain-death.patch. I didn't write it, and the explanation isn't specific, but I think the purpose is to all resources are released before the OpenXT toolstack proceeds with (blktap) cleanup. Maybe a new `xl shutdown` flag to wait for domain destruction would be worthwhile? Regards, Jason
Jason Andryuk writes ("Re: [OSSTEST PATCH 01/38] ts-logs-capture: Cope if xl shutdown leaves domain running for a bit"):
> My understanding is shutdown happens first when the guest stops and
> destruction happens afterward when all the resources are cleaned up.
> So your race is that the domain shutdown, but it still shows up in `xl
> list` since it hasn't been destroyed.
>
> OpenXT has a hack to only wait for destruction
> https://github.com/OpenXT/xenclient-oe/blob/master/recipes-extended/xen/files/xl-shutdown-wait-for-domain-death.patch.
> I didn't write it, and the explanation isn't specific, but I think the
> purpose is to all resources are released before the OpenXT toolstack
> proceeds with (blktap) cleanup.
>
> Maybe a new `xl shutdown` flag to wait for domain destruction would be
> worthwhile?
Yes! Repeating the -w flag maybe.
Ian.
diff --git a/ts-logs-capture b/ts-logs-capture index 0320a5a5..d75a2fda 100755 --- a/ts-logs-capture +++ b/ts-logs-capture @@ -272,6 +272,7 @@ sub shutdown_guests () { ( xl shutdown -a -F -w ; echo y ) & ) | ( read x + sleep 10 # xl shutdown is a bit racy :-/ xl list | awk '!/^Domain-0 |^Name / {print $2}' \ | xargs -t -r -n1 xl destroy ||: )
This seems mostly to affect buster but it could in principle affect earlier releases too I think. In principle it would be nice to fix this bug, and to have a proper test for it, but a reliable test is hard and an unreliable one is not useful. So I guess we are going to have this workaround indefinitely... Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com> --- ts-logs-capture | 1 + 1 file changed, 1 insertion(+)