@Dag, you might want to check with Mike Tutkowski, how he implemented this for the "online storage migration" from other storages (CEPH and NFS implemented so far as sources) to SolidFire.
We are doing exactly the same demo/manual way (this is what Mike has sent me back in the days), so perhaps you want to see how to translate this into general things (so ANY to ANY storage migration) inside CloudStack. Cheers On 2 February 2018 at 10:28, Dag Sonstebo <dag.sonst...@shapeblue.com> wrote: > All > > I am doing a bit of R&D around this for a client at the moment. I am > semi-successful in getting live migrations to different storage pools to > work. The method I’m using is as follows – this does not take into account > any efficiency optimisation around the disk transfer (which is next on my > list). The below should answer your question Eric about moving to a > different location – and I am also working with your steps to see where I > can improve the following. Keep in mind all of this is external to > CloudStack – although CloudStack picks up the destination KVM host > automatically it does not update the volume tables etc., neither does it do > any housekeeping. > > 1) Ensure the same network bridges are up on source and destination – > these are found with: > > [root@kvm1 ~]# virsh dumpxml 9 | grep source > <source file='/mnt/00e88a7b-985f-3be8-b717-0a59d8197640/d0ab5dd5- > e3dd-47ac-a326-5ce3d47d194d'/> > <source bridge='breth1-725'/> > <source path='/dev/pts/3'/> > <source path='/dev/pts/3'/> > > So from this make sure breth1-725 is up on the destionation host (do it > the hard way or cheat and spin up a VM from same account and network on > that host) > > 2) Find size of source disk and create stub disk in destination (this part > can be made more efficient to speed up disk transfer – by doing similar > things to what Eric is doing): > > [root@kvm1 ~]# qemu-img info /mnt/00e88a7b-985f-3be8-b717- > 0a59d8197640/d0ab5dd5-e3dd-47ac-a326-5ce3d47d194d > image: /mnt/00e88a7b-985f-3be8-b717-0a59d8197640/d0ab5dd5-e3dd- > 47ac-a326-5ce3d47d194d > file format: qcow2 > virtual size: 8.0G (8589934592 bytes) > disk size: 32M > cluster_size: 65536 > backing file: /mnt/00e88a7b-985f-3be8-b717-0a59d8197640/3caaf4c9-eaec- > 11e7-800b-06b4a401075c > > ###################### > > [root@kvm3 50848ff7-c6aa-3fdd-b487-27899bf2129c]# qemu-img create -f > qcow2 d0ab5dd5-e3dd-47ac-a326-5ce3d47d194d 8G > Formatting 'd0ab5dd5-e3dd-47ac-a326-5ce3d47d194d', fmt=qcow2 > size=8589934592 encryption=off cluster_size=65536 > [root@kvm3 50848ff7-c6aa-3fdd-b487-27899bf2129c]# qemu-img info > d0ab5dd5-e3dd-47ac-a326-5ce3d47d194d > image: d0ab5dd5-e3dd-47ac-a326-5ce3d47d194d > file format: qcow2 > virtual size: 8.0G (8589934592 bytes) > disk size: 448K > cluster_size: 65536 > > 3) Rewrite the new VM XML file for the destination with: > a) New disk location, in this case this is just a new path (Eric – this > answers your question) > b) Different IP addresses for VNC – in this case 10.0.0.1 to 10.0.0.2 > and carry out migration. > > [root@kvm1 ~]# virsh dumpxml 9 | sed -e 's/00e88a7b-985f-3be8-b717- > 0a59d8197640/50848ff7-c6aa-3fdd-b487-27899bf2129c/g' | sed -e 's/ > 10.0.0.1/10.0.0.2/g' > /root/i-2-14-VM.xml > > [root@kvm1 ~]# virsh migrate --live --persistent --copy-storage-all --xml > /root/i-2-14-VM.xml i-2-14-VM qemu+tcp://10.0.0.2/system --verbose > --abort-on-error > Migration: [ 25 %] > > 4) Once complete delete the source file. This can be done with extra > switches on the virsh migrate command if need be. > = = = > > In the simplest tests this works – destination VM remains online and has > storage in new location – but it’s not persistent – sometimes the > destination VM ends up in a paused state, and I’m working on how to get > around this. I also noted virsh migrate has a migrate-setmaxdowntime which > I think can be useful here. > > Regards, > Dag Sonstebo > Cloud Architect > ShapeBlue > > On 01/02/2018, 20:30, "Andrija Panic" <andrija.pa...@gmail.com> wrote: > > Actually, we have this feature (we call this internally > online-storage-migration) to migrate volume from CEPH/NFS to SolidFire > (thanks to Mike Tutkowski) > > There is libvirt mechanism, where basically you start another PAUSED > VM on > another host (same name and same XML file, except the storage volumes > are > pointing to new storage, different paths, etc and maybe VNC listening > address needs to be changed or so) and then you issue on original > host/VM > the live migrate command with few parameters... the libvirt will > transaprently handle the copy data process from Soruce to New volumes, > and > after migration the VM will be alive (with new XML since have new > volumes) > on new host, while the original VM on original host is destroyed.... > > (I can send you manual for this, that is realted to SF, but idea is the > same and you can exercies this on i.e. 2 NFS volumes on 2 different > storages) > > This mechanism doesn't exist in ACS in general (AFAIK), except for when > migrating to SolidFire. > > Perhaps community/DEV can help extend Mike's code to do same work on > different storage types... > > Cheers > > > dag.sonst...@shapeblue.com > www.shapeblue.com > 53 Chandos Place, Covent Garden, London WC2N 4HSUK > @shapeblue > > > > On 19 January 2018 at 18:45, Eric Green <eric.lee.gr...@gmail.com> wrote: > > > KVM is able to live migrate entire virtual machines complete with > local > > volumes (see 'man virsh') but does require nbd (Network Block > Device) to be > > installed on the destination host to do so. It may need installation > of > > later libvirt / qemu packages from OpenStack repositories on Centos > 6, I'm > > not sure, but just works on Centos 7. In any event, I have used this > > functionality to move virtual machines between virtualization hosts > on my > > home network. It works. > > > > What is missing is the ability to live-migrate a disk from one shared > > storage to another. The functionality built into virsh live-migrates > the > > volume ***to the exact same location on the new host***, so > obviously is > > useless for migrating the disk to a new location on shared storage. I > > looked everywhere for the ability of KVM to live migrate a disk from > point > > A to point B all by itself, and found no such thing. libvirt/qemu > has the > > raw capabilities needed to do this, but it is not currently exposed > as a > > single API via the qemu console or virsh. It can be emulated via > scripting > > however: > > > > 1. Pause virtual machine > > 2. Do qcow2 snapshot. > > 3. Detach base disk, attach qcow2 snapshot > > 4. unpause virtual machine > > 5. copy qcow2 base file to new location > > 6. pause virtual machine > > 7. detach snapshot > > 8. unsnapshot qcow2 snapshot at its new location. > > 9. attach new base at new location. > > 10. unpause virtual machine. > > > > Thing is, if that entire process is not built into the underlying > > kvm/qemu/libvirt infrastructure as tested functionality with a > defined API, > > there's no guarantee that it will work seamlessly and will continue > working > > with the next release of the underlying infrastructure. This is using > > multiple different tools to manipulate the qcow2 file and > attach/detach > > base disks to the running (but paused) kvm domain, and would have to > be > > tested against all variations of those tools on all supported > Cloudstack > > KVM host platforms. The test matrix looks pretty grim. > > > > By contrast, the migrate-with-local-storage process is built into > virsh > > and is tested by the distribution vendor and the set of tools > provided with > > the distribution is guaranteed to work with the virsh / libvirt/ qemu > > distributed by the distribution vendor. That makes the test matrix > for > > move-with-local-storage look a lot simpler -- "is this functionality > > supported by that version of virsh on that distribution? Yes? Enable > it. > > No? Don't enable it." > > > > I'd love to have live migration of disks on shared storage with > Cloudstack > > KVM, but not at the expense of reliability. Shutting down a virtual > machine > > in order to migrate one of its disks from one shared datastore to > another > > is not ideal, but at least it's guaranteed reliable. > > > > > > > On Jan 19, 2018, at 04:54, Rafael Weingärtner < > > rafaelweingart...@gmail.com> wrote: > > > > > > Hey Marc, > > > It is very interesting that you are going to pick this up for KVM. > I am > > > working in a related issue for XenServer [1]. > > > If you can confirm that KVM is able to live migrate local volumes > to > > other > > > local storage or shared storage I could make the feature I am > working on > > > available to KVM as well. > > > > > > > > > [1] https://issues.apache.org/jira/browse/CLOUDSTACK-10240 > > > > > > On Thu, Jan 18, 2018 at 11:35 AM, Marc-Aurèle Brothier < > > ma...@exoscale.ch> > > > wrote: > > > > > >> There's a PR waiting to be fixed about live migration with local > volume > > for > > >> KVM. So it will come at some point. I'm the one who made this PR > but I'm > > >> not using the upstream release so it's hard for me to debug the > problem. > > >> You can add yourself to the PR to get notify when things are > moving on > > it. > > >> > > >> https://github.com/apache/cloudstack/pull/1709 > > >> > > >> On Wed, Jan 17, 2018 at 10:56 AM, Eric Green < > eric.lee.gr...@gmail.com> > > >> wrote: > > >> > > >>> Theoretically on Centos 7 as the host KVM OS it could be done > with a > > >>> couple of pauses and the snapshotting mechanism built into > qcow2, but > > >> there > > >>> is no simple way to do it directly via virsh, the libvirtd/qemu > control > > >>> program that is used to manage virtualization. It's not as with > > issuing a > > >>> simple vmotion 'migrate volume' call in Vmware. > > >>> > > >>> I scripted out how it would work without that direct support in > > >>> libvirt/virsh and after looking at all the points where things > could go > > >>> wrong, honestly, I think we need to wait until there is support > in > > >>> libvirt/virsh to do this. virsh clearly has the capability > internally > > to > > >> do > > >>> live migration of storage, since it does this for live domain > migration > > >> of > > >>> local storage between machines when migrating KVM domains from > one host > > >> to > > >>> another, but that capability is not currently exposed in a way > > Cloudstack > > >>> could use, at least not on Centos 7. > > >>> > > >>> > > >>>> On Jan 17, 2018, at 01:05, Piotr Pisz <pp...@pulab.pl> wrote: > > >>>> > > >>>> Hello, > > >>>> > > >>>> Is there a chance that one day it will be possible to migrate > volume > > >>> (root disk) of a live VM in KVM between storage pools (in > CloudStack)? > > >>>> Like a storage vMotion in Vmware. > > >>>> > > >>>> Best regards, > > >>>> Piotr > > >>>> > > >>> > > >>> > > >> > > > > > > > > > > > > -- > > > Rafael Weingärtner > > > > > > > -- > > Andrija Panić > > > -- Andrija Panić
