KVM live migration for non shared lvm storage

Question

I am trying to live migrate my KVM based VM from one host to another for non shared storage using virsh migrate. I have set both the hostnames at /etc/hosts on each of the host. Also I have set passwordless SSH between the hosts. Still i am not able to live migrate my VM.

Steps I followed:

Created a vm on host1 with a lv
Created a dummy lv on host2
symlink the host2 lv with host1 vm disk
executed command: virsh migrate --live --persistent --verbose --copy-storage-all --dname test_1 --desturi qemu+ssh://root@host2/system v1007

I get error:

error: internal error: cannot precreate storage for disk type 'block'

Can anyone help to sort this issue? Is anything that I might be missing out? Thank you

@MichaelHampton libvirtd (libvirt) 4.5.0 storage is lvm based What else do you require can you please specify. — Ash, Jul 09 '20 at 12:37
Why isn't your system up to date? There is a known bug that fixes this problem but that was years ago, and CentOS 7.0 did not have the fix. You should be updating your system on a regular basis. — Michael Hampton, Jul 09 '20 at 13:01
Here is a bug description - https://bugs.centos.org/view.php?id=8281 — batistuta09, Jul 09 '20 at 14:57
@MichaelHampton thank you. i updated Name : qemu-kvm Arch : x86_64 Epoch : 10 Version : 1.5.3 Release : 173.el7_8.3 Size : 1.9 M Repo : updates/7/x86_64 but still it did not help — Ash, Jul 10 '20 at 06:24

score 1 · Answer 1 · answered Jul 10 '20 at 10:17

This sounds like a known bug in early versions of qemu.

I don't think this bug was ever fixed in the ancient version of qemu-kvm shipped with base CentoS 7.

However, AFAIK it is fixed in the CentOS Virt SIG's release of qemu-kvm-ev, which is much newer, and tracks the source code for the enterprise Red Hat Virtualization product. I use this on some CentOS 7 hypervisors and live migration works well.

You can update to the Virt SIG builds by simply enabling their repo and then updating your system:

yum install centos-release-qemu-ev
yum distro-sync

After this update you should reboot the computer to ensure that everything is started with the new packages.

KVM live migration for non shared lvm storage

1 Answers1