[ovirt-users] MOM crashes ovirt-guest-agent

[Yaniv Dary]

Can you please open a bug?
https://bugzilla.redhat.com/enter_bug.cgi?product=ovirt-guest-agent

Yaniv Dary
Technical Product Manager
Red Hat Israel Ltd.
34 Jerusalem Road
Building A, 4th floor
Ra'anana, Israel 4350109

Tel : +972 (9) 7692306
        8272306
Email: ydary at redhat.com
IRC : ydary


On Fri, Mar 18, 2016 at 6:20 PM, Martin Sivak <msivak at redhat.com> wrote:

> > Whats extremely prone to errors is the way the guest agent checks the
> active user in GuestAgentLinux2.py line 325:
> >
> > users = os.popen('/usr/bin/users').read().split()
>
> That is something we could probably improve. The maintainer is Vinzenz
> Feenstra.
>
> Martin
>
>
> On Fri, Mar 18, 2016 at 3:13 PM, Andreas Trawöger
> <andreas.trawoeger at qitasc.com> wrote:
> > Hi Martin,
> >
> > Whats extremely prone to errors is the way the guest agent checks the
> active user in GuestAgentLinux2.py line 325:
> >
> > users = os.popen('/usr/bin/users').read().split()
> >
> > This creates a new subprocess every time it is executed and if that
> doesn't work for whatever reason the ovirt guest agent crashes instantly.
> >
> > But I probably should make that suggestions on the devel list.
> >
> > Regards
> >
> > ________________________________________
> > Von: Martin Sivak <msivak at redhat.com>
> > Gesendet: Freitag, 18. März 2016 14:44
> > An: Andreas Trawöger
> > Cc: oVirt Userlist
> > Betreff: Re: [ovirt-users] MOM crashes ovirt-guest-agent
> >
> > Hi,
> >
> > it is not really a bug. You should give the VM more memory if you
> > expect that it will need it that fast. The ballooning mechanism has
> > its disadvantages and this is one of those. We do not react fast
> > enough when such a fast allocation happens.
> >
> > There is really not much we can do from the mom / guest agent side. We
> > could slowly increase the available memory when the guest agent dies
> > (pretty easy to implement) and we might inform the system that a guest
> > agent is an important process (if that is even possible) so OOM killer
> > will avoid it. But that would not help with Cannot allocate memory
> > error as even the OOM killer takes time before it reacts.
> >
> > Using low guaranteed memory values with ballooning for critical VMs is
> > probably not the best idea.
> >
> > Regards
> >
> > --
> > Martin Sivak
> > msivak at redhat.com
> > SLA / oVirt
> >
> > On Fri, Mar 18, 2016 at 1:00 PM, Andreas Trawöger
> > <andreas.trawoeger at qitasc.com> wrote:
> >> Hi,
> >>
> >>
> >> I'm trying to track down why my Foreman Centos7 VM continuously crashes
> with
> >> out of Memory errors on my ovirt-3.6 hosts and what seems to happen is
> the
> >> following:
> >>
> >>
> >> 1. The Foreman VM only uses 1GB at the beginning and MOM over time
> reduces
> >> the memory size from 8GB Ram to the defined minimum of 2GB
> >>
> >>
> >> mom.log:
> >> 2016-03-18 12:25:42,669 - mom.Controllers.Balloon - INFO - Ballooning
> >> guest:qvie-foreman from 2210584 to 2100054
> >>
> >>
> >> 2. When the VM needs RAM very quickly like if you do an 'cp /dev/zero
> >> /run/zero' the ovirt guest agent crashes with an out of memory error.
> >>
> >>
> >> ovirt-guest-agent.log:
> >>
> >> Traceback (most recent call last):
> >>   File "/usr/share/ovirt-guest-agent/OVirtAgentLogic.py", line 239, in
> >> doWork
> >>     self.sendUserInfo()
> >>   File "/usr/share/ovirt-guest-agent/OVirtAgentLogic.py", line 355, in
> >> sendUserInfo
> >>     cur_user = self.dr.getActiveUser()
> >>   File "/usr/share/ovirt-guest-agent/GuestAgentLinux2.py", line 325, in
> >> getActiveUser
> >>     users = os.popen('/usr/bin/users').read().split()
> >> OSError: [Errno 12] Cannot allocate memory
> >>
> >> 3. Resulting in an MOM warning that it can't get any memory stats from
> the
> >> VM. Leaving the memory size at its minimum size:.
> >>
> >>
> >> mom.log:
> >>
> >> mom.Collectors.GuestMemory - WARNING - getVmMemoryStats() error: The
> >> ovirt-guest-agent is not active
> >>
> >>
> >> Any chances to prevent that from happening? Or is this a bug in MOM /
> >> ovirt-guest-agent that should be fixed?
> >>
> >>
> >> Greetings
> >>
> >> Andreas
> >>
> >>
> >> _______________________________________________
> >> Users mailing list
> >> Users at ovirt.org
> >> http://lists.ovirt.org/mailman/listinfo/users
> >>
> _______________________________________________
> Users mailing list
> Users at ovirt.org
> http://lists.ovirt.org/mailman/listinfo/users
>
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