Cinder

[docs] Cannot start vm from disk with burst qos

Bug #1982945 reported by Vladislav Belogrudov on 2022-07-27

This bug affects 1 person

Affects		Status	Importance	Assigned to	Milestone
	Cinder	New	Wishlist	Unassigned

Bug Description

when trying to run a VM from a disk associated with burst qos consumer=both total_iops_sec_max=200 , nova/libvirt reports:

Failed to start libvirt guest: libvirt.libvirtError: internal error: unable to execute QEMU command 'block_set_io_throttle': bps_max/iops_max require corresponding bps/iops values

Also when setting up size_iops_sec:
nova.virt.libvirt.guest libvirt.libvirtError: internal error: unable to execute QEMU command 'block_set_io_throttle': iops size requires an iops value to be set

OpenStack Yoga, CentOS Stream 8
libvirt 8.0.0-2
qemu 6.2.0-5
cinder backend: lvm (can be any other iscsi storage as well)

Tags:

Revision history for this message

Vladislav Belogrudov (vlad-belogrudov) wrote on 2022-07-27:

log.txt Edit (7.1 KiB, text/plain)

Revision history for this message

Vladislav Belogrudov (vlad-belogrudov) wrote on 2022-07-28:

it looks like incorrect/incomplete documentation.
According to https://github.com/qemu/qemu/blob/master/docs/throttle.txt for burst max values it is necessary to also provide period and normal limits.

Revision history for this message

Balazs Gibizer (balazs-gibizer) wrote on 2022-08-16:

Nova only acts based on the qos policy from cinder. So I'm moving this bug to cinder. I suspect that this is either a doc bug on cinder to state in the doc that these qos configs needs to be set together (e.g. total_iops_sec_max needs to be set together with total_iops_sec) or maybe a cinder change that validates on the qos API that valid pairs are set.

affects:

nova → cinder

Sofia Enriquez (lsofia-enriquez) on 2022-08-24

Changed in cinder:
importance:	Undecided → Wishlist
tags:	added: libvirt lvm qos
summary:	- cannot start vm from disk with burst qos + [docs] Cannot start vm from disk with burst qos
tags:	added: drivers