(Last Updated On: August 17, 2018)

Have you ever receive error message like below while working with Openstack and KVM?. If so, a fix is given here.

Command: env LC_ALL=C LANG=C qemu-img info /var/lib/libvirt/images/asterisk.qcow2
Exit code: 1
Stdout: u”
Stderr: u”qemu-img: Could not open ‘/var/lib/libvirt/images/asterisk.qcow2’: Could not open ‘/var/lib/libvirt/images/asterisk.qcow2’: Permission deniedn”

INFO nova.compute.resource_tracker [req-7f9e4964-52c0-4204-ae00-b74fb83acb9c – – – – -] Auditing locally available compute resources for node localhost.localdomain
 ERROR nova.compute.manager [req-7f9e4964-52c0-4204-ae00-b74fb83acb9c – – – – -] Error updating resources for node localhost.localdomain: Unexpected error while running command.
This is a qemu error,in the sense that nova does not have permissions to write/read to the specified qcow2 file.
Stop the libvirtd service

[[email protected] ~(keystone)]# systemctl stop libvirtd.service 

Then set user and group to nova service
Set the dynamic_ownership to zero

[[email protected] ~(keystone)]# vim  /etc/libvirt/qemu.conf
 user = "nova"

# The group for QEMU processes run by the system instance. It can be
# specified in a similar way to user.

group = "nova"

# Whether libvirt should dynamically change file ownership
# to match the configured user/group above. Defaults to 1.
# Set to 0 to disable file ownership changes.

dynamic_ownership = 0

Save the file and restart libvirtd service

[[email protected] ~(keystone)]# systemctl start libvirtd.service

and you will be good