Description of problem: Metrics for RHEL 8 Guest OS memory are not displayed on RHV-M UI. On the RHV-M UI, navigate to Compute > Virtual Machines > select RHEL 8 VM. Guest OS Memory Free/Cached/Buffered: Not Configured Version-Release number of selected component (if applicable): Host: OS Version: RHEL - 8.3 - 2.el8ev OS Description: Red Hat Virtualization Host 4.4.3 (el8.3) Kernel Version: 4.18.0 - 240.8.1.el8_3.x86_64 KVM Version: 5.1.0 - 14.module+el8.3.0+8790+80f9c6d8.1 LIBVIRT Version: libvirt-6.6.0-7.1.module+el8.3.0+8852+b44fca9f VDSM Version: vdsm-4.40.35.1-1.el8ev Virtual Machine: RHEL 8.3 qemu-guest-agent-15:4.2.0-34.module+el8.3.0+9828+7aab3355.3.x86_64 or qemu-guest-agent-15:4.2.0-34.module+el8.3.0+8829+e7a0a3ea.1.x86_64 How reproducible: 100% Steps to Reproduce: 1. Build RHEL 8 VM 2. Confirm qemu-guest-agent is installed, enabled and running. # systemctl status qemu-guest-agent 3. On RHV-M UI, navigate to Compute > Virtual Machines > select RHEL 8 VM. Actual results: Under Compute > Virtual Machines > select RHEL 8 VM > General tab Guest OS Memory Free/Cached/Buffered: Not Configured Expected results: Metrics for 'Guest OS Memory Free/Cached/Buffered:' should be displayed for RHEL 8 virtual machines. Additional info: RHEL 7 virtual machines with ovirt-guest-agent-common installed, display metrics. Guest OS Memory Free/Cached/Buffered: 1296 / 2 / 301 MB
RFE for QGA?
No this is not RFE for QGA. We don't use agent for gathering memory statistics any more but query such information from the balloon driver in guest OS. When we switched to balloon driver and deprecated ovirt-guest-agent, this information was not available so we stopped reporting it to engine. We reintroduced the caches/buffers later again (provided guest OS kernel is 4.16 or newer) in 4.3 (bug 1687832) but it is for internal purposes (MOM) only and is still not reported to engine. The complication here is that we don't have this information as two separate values buffers and caches but only a sum. So we can either reuse one of the stats for this (e.g. mem_cached and keep mem_buffers equal 0) which may be confusing or engine can compute the value on its own by subtracting mem_unused from mem_free. Either way we need to change how we represent the values in UI.
Ack, thanks Tomáš So adding bz 1917718 as a dependency and let's add their combined value (I think it would make more sense to compute it and stored it in a different DB field because of the DWH views).
To sum up the internal discussion -- we are not going to do any changes in VDSM and its API. Engine can compute the the sum of buffers and caches from existing stats by using the formula: buffers_caches = mem_free - mem_unused. Engine will store the computed value in new field (will not reuse mem_buffers or mem_cached) and the UI will be redesigned to compensate for the fact that we don't have two separate values anymore. Engine should resort to the computation if mem_cached and mem_buffers are either missing (cases when ovirt-guest-agent is not running) as well as when both mem_cached and mem_buffers equal zero (case of Windows with ovirt-guest-agent installed).
Verified on: ovirt-engine-4.4.6.6-0.10.el8ev.noarch Steps: 1. In the UI, open the detailed information for a RHEL8 VM Results: On general tab, information of "Guest OS Memory Free/Cached+Buffered" memory is shown as expected
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory (Moderate: RHV Manager security update (ovirt-engine) [ovirt-4.4.6]), and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHSA-2021:2179
Due to QE capacity, we are not going to cover this issue in our automation