Description of problem:
In automation test i have a nagtive test that checks if the balloon is not working without Guset Agent.
in this test, i see that the ballooning is working fine without the Guest Agent on rhel VM.

msivak explained that it happens cause :
The configuration uses GuestMemoryOptional and the policy tests for (valid guest.balloon_cur (guest.StatAvg "mem_unused") properly.

Unfortunately the StatAvg method returns 0 which is considered a valid value.

Create a bug number and I will fix that. You can test a probable fix by changing the 02-balloon file to use: (valid guest.balloon_cur (guest.Stat "mem_unused") instead.


Version-Release number of selected component (if applicable):
vdsm-4.16.16-1.el7ev.x86_64
mom-0.4.1-5.el7ev.noarch

How reproducible:
100*

Steps to Reproduce:
0. make sure the overcommit is disabeld
   - go to Clusters
   - right click on the cluster -> edit
   - go to Optimization tab
   - make sure this radio button is chosen: None - Disable memory overcommit

1.enable ballooning on the cluster :
  - go to Clusters
  - right click on the cluster -> edit
  - go to Optimization tab
  - enable the checkbox : Enable Memory Balloon Optimization

2.Sync mom policy
  - go to Clusters
  - choose your cluster
  - on the cluster sub tab choose your hosts and click on 'Sync MoM policy'

3.Create VM with OS installed (512MB guaranteed memory / 2GB full memory) without Guest Agent

4. on the host, change in the file  "/etc/vdsm/mom.d/02-balloon.policy" from defvar pressure_threshold 0.20 to defvar pressure_threshold 0.40 - to make ballooning Run faster

5. Run memory load on host

6. chack the in vdsClient if the ballooning is working.
   the spesific command: vdsClient -s <HOST_NAME> getVmStats <VM_ID> | grep   balloon
   if the current_balloon < max_balloon is True then the ballooning is working. 

Actual results:
the balooning is working on the VM with no guest agent.

Expected results:
the balloning shouldn't work

Additional info:
mom log : 

2015-06-09 16:58:52,185 - mom.Monitor - INFO - GuestMonitor-mom-1 is ready
2015-06-09 17:05:52,748 - mom.Monitor - INFO - GuestMonitor-mom-1 ending
2015-06-09 17:06:37,693 - mom.Monitor - INFO - GuestMonitor-mom-1 starting
2015-06-09 17:06:37,695 - mom.Collectors.GuestMemory - WARNING - getVmMemoryStats() error: The ovirt-guest-agent is not active
2015-06-09 17:06:52,716 - mom.Monitor - INFO - GuestMonitor-mom-1 is ready
2015-06-09 17:08:17,839 - mom.Collectors.GuestMemory - WARNING - getVmMemoryStats() error: The ovirt-guest-agent is not active
2015-06-09 17:09:01,015 - mom.Controllers.Balloon - INFO - Ballooning guest:mom-1 from 2097152 to 1992294
2015-06-09 17:10:08,001 - mom.Monitor - INFO - GuestMonitor-mom-1 ending