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

> 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(a)qitasc.com&gt; 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(a)redhat.com&gt; > 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(a)redhat.com > SLA / oVirt > > On Fri, Mar 18, 2016 at 1:00 PM, Andreas Trawöger > <andreas.trawoeger(a)qitasc.com&gt; 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(a)ovirt.org >> http://lists.ovirt.org/mailman/listinfo/users >> _______________________________________________ Users mailing list Users(a)ovirt.org http://lists.ovirt.org/mailman/listinfo/users