Note: This bug is displayed in read-only format because the product is no longer active in Red Hat Bugzilla.

RHEL Engineering is moving the tracking of its product development work on RHEL 6 through RHEL 9 to Red Hat Jira (issues.redhat.com). If you're a Red Hat customer, please continue to file support cases via the Red Hat customer portal. If you're not, please head to the "RHEL project" in Red Hat Jira and file new tickets here. Individual Bugzilla bugs in the statuses "NEW", "ASSIGNED", and "POST" are being migrated throughout September 2023. Bugs of Red Hat partners with an assigned Engineering Partner Manager (EPM) are migrated in late September as per pre-agreed dates. Bugs against components "kernel", "kernel-rt", and "kpatch" are only migrated if still in "NEW" or "ASSIGNED". If you cannot log in to RH Jira, please consult article #7032570. That failing, please send an e-mail to the RH Jira admins at rh-issues@redhat.com to troubleshoot your issue as a user management inquiry. The email creates a ServiceNow ticket with Red Hat. Individual Bugzilla bugs that are migrated will be moved to status "CLOSED", resolution "MIGRATED", and set with "MigratedToJIRA" in "Keywords". The link to the successor Jira issue will be found under "Links", have a little "two-footprint" icon next to it, and direct you to the "RHEL project" in Red Hat Jira (issue links are of type "https://issues.redhat.com/browse/RHEL-XXXX", where "X" is a digit). This same link will be available in a blue banner at the top of the page informing you that that bug has been migrated.

Description of problem:
  VM cannot start OS if change its IDE disk to virtio one after adding a virtio disk.

Version-Release number of selected component (if applicable):
libvirt-0.10.2-10.el6.x86_64
virt-manager-0.9.0-18.el6.x86_64

Reproduce steps:
1. Install a guest on an IDE disk.
2. Add a virtio disk as its second disk.
3. Destroy the guest, then change its IDE disk to virtio
4. Start the guest.

Actual results:
1. Guest will boot in the disk added by step 2, then report an error: no bootable device.

Expected results:
1. Guest could start OS normally.

Additional info:
1. Looks this issue caused by disk number, second disk becomes vda and IDE disk was changed as vdb. We can insert a line <boot order='1'/> into guest's xml through virsh command as a work around, but there's no way to do this through virt-manager. I think virt-manager could provide an option, allows user to mark a disk as an "OS disk", no matter how many disks exist, the "OS disk" will always be the first one.
2. if I set virtio disk as boot disk, then add aa IDE disk as second one,then change the virtio disk to IDE,the guest can not start os either.

Could reproduce this issue with virt-manager-0.9.0-19.el6.x86_64 on latest rhel6.5


Reproduce steps:
1. Install a guest on an IDE disk.
2. Add a virtio disk as its second disk.
3. Destroy the guest, then change its IDE disk to virtio
4. Start the guest.

Guest will boot in the disk added by step 2, then report an error: no bootable device.

the upstream version permits to choose the boot order of each device individually.  I am going to close it as the back-port is not trivial and exists a workaround for it.