Bug 2218211

Summary: ceilometer_memory_usage fails to report metrics in case where VMs disks are stored at ceph
Product: Red Hat OpenStack Reporter: Leonid Natapov <lnatapov>
Component: openstack-ceilometerAssignee: Yadnesh Kulkarni <ykulkarn>
Status: ASSIGNED --- QA Contact: Leonid Natapov <lnatapov>
Severity: medium Docs Contact:
Priority: medium    
Version: 17.1 (Wallaby)CC: apevec, mrunge, ykulkarn
Target Milestone: z2Keywords: Triaged
Target Release: 17.1Flags: ifrangs: needinfo? (ykulkarn)
Hardware: Unspecified   
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Description Leonid Natapov 2023-06-28 13:08:44 UTC 
ceilometer_memory_usage fails to report metrics in case where VMs disks are stored at ceph

I have an OSPdO running OSP 16.2 in HCI env. 
I have noticed that there is  no data in VM Memory Utilization panel in Grafana.

After checking compute.log in ceilometer directory on compute nodes I see the following message


ceilometer_memory_usage shows no data
6:56
2023-06-28 03:33:36.063 15 WARNING ceilometer.compute.pollsters [-] memory.usage statistic in not available for instance 93366f22-da75-4df1-bb64-ef5710d123a7: ceilometer.compute.pollsters.NoVolumeException
Comment 4 Yadnesh Kulkarni 2023-07-03 14:17:58 UTC 
Looks like libvirt itself cannot expose the memory statistics of an instance in an HCI env
~~~
[root@computehci-1 /]# virsh list
 Id   Name                State
-----------------------------------
 1    instance-00000001   running
 2    instance-00000003   running

[root@computehci-1 /]# virsh dommemstat 1                                                                                                                                                                                              
actual 524288
last_update 0
rss 228372

[root@computehci-1 /]# virsh dommemstat 2
actual 524288
last_update 0
rss 209964
~~~

From a compute node of non-HCI env but nova uses ceph as a backend
~~~
[root@compute-0 /]# virsh list
 Id   Name                State
-----------------------------------
 1    instance-00000001   running

[root@compute-0 /]# virsh dommemstat instance-00000001
actual 524288
swap_in 0
swap_out 0
major_fault 0
minor_fault 84757
unused 402840
available 477392
usable 431064
last_update 1688384922
disk_caches 26528
hugetlb_pgalloc 0
hugetlb_pgfail 0
rss 353636
~~~

Ceilometer uses these readings to generate memory usage samples [1] which are missing in HCI env.

We must analyze this behaviour in OSP17 as well.

[1] https://github.com/openstack/ceilometer/blob/stable/train/ceilometer/compute/virt/libvirt/inspector.py#L171-L185