Red Hat Bugzilla – Bug 795127
pre-migration hook needed at destination
Last modified: 2012-06-20 02:48:39 EDT
Description of problem: virDomainMigrateURI2() lets the client play with the domxml at the destination host. However, more common than not, the client does not (or should not) know about specifics of the destination host (where storage is mounted there, name of network interface, ...). I would like to be able to tweak incoming domxml at the destination host before `qemu -incoming` is started. This would let a complex client application mount storage, activate LVs, create local cdrom image for vm-specific data (and much more) before the VM starts.
Initial patches sent upstream for review: https://www.redhat.com/archives/libvir-list/2012-February/msg01146.html
In POST: http://post-office.corp.redhat.com/archives/rhvirt-patches/2012-February/msg01599.html
Hi Jiri, What should I write on qemu hooks on source and target host?
The hook will only be called on target host as /etc/libvirt/hooks/qemu DOMAIN migrate begin - with the DOMAIN's XML sent to stdin of the script. So you need to do something in the script when $2 is equal to "migrate". You can either do nothing (i.e, exit 0) or copy stdin to stdout (e.g., cat) to use the domain XML without any changes. Or you can try to change something in the input XML (using sed, for example).
Verify it with libvirt-0.9.10-4.el6.x86_64 and it passed: 1 setup migration env on both source and target machine 2 prepare /etc/libvirt/hooks/qemu script file on target machine: # cat /etc/libvirt/hooks/qemu #! /bin/bash echo "$0" "$@" >> /tmp/qemu.log exit 0 # chmod +x /etc/libvirt/hooks/qemu 3 start migration # virsh migrate ${guestname} qemu+ssh://${target_ip}/system --unsafe 4 check /tmp/qemu.log on target machine: # cat /tmp/qemu.log /etc/libvirt/hooks/qemu kvm-rhel6-i386 migrate begin - /etc/libvirt/hooks/qemu kvm-rhel6-i386 prepare begin - /etc/libvirt/hooks/qemu kvm-rhel6-i386 start begin -
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, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. http://rhn.redhat.com/errata/RHSA-2012-0748.html