5:13 p.m.
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>
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> 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