[ovirt-users] 3.5 live merge findings and mysteries [was Re: Simple way to activate live merge in FC20 cluster]

[Adam Litke]

Hi, please see below for more details.

tl; dr;  Live merge works on oVirt-3.5.0 with Fedora 20 hosts that are using qemu and libvirt packages from the virt-preview repo.
No other configuration is supported yet.  We aim to have support for RHEL7.1 and later and built-in support for Fedora 21.

----- Original Message -----
> 
> On Fri, Dec 12, 2014 at 4:32 PM, Itamar Heim < iheim at redhat.com > wrote:
> 
> 
> On 11/21/2014 09:53 AM, Gianluca Cecchi wrote:
> 
> 
> 
> So the official statement is this one at:
> http://www.ovirt.org/OVirt_3. 5_Release_Notes
> 
> Live Merge
> If an image has one or more snapshots, oVirt 3.5's merge command will
> combine the data of one volume into another. Live merges can be
> performed with data is pulled from one snapshot into another snapshot.
> The engine can merge multiple disks at the same time and each merge can
> independently fail or succeed in each operation.
> 
> I think we should remove the part above, or at least have some of the
> developers to better clarify it.
> The feature in my opinion is very important and crucial for oVirt/RHEV
> because it is able to almost-fill the gap with VMware, especially in
> development environments, where having flexibility on snapshots
> management is very important and could be a starting point to have
> greater user base familiarize with the product and adopt it.
> 
> So these are my findings and all combinations and none of them was able
> to provide live merge....
> Could anyone tell me where I'm failing? Or correct release notes?
> 
> 1) Environment with All-In-One F20
> 
> installing oVirt AIO on F20 automatically gives the virt-preview repo
> through the ovirt-3.5-dependencies.repo file, but only for libvirt*
> packages:
> 
> the same server is the engine and the hypervisor
> 
> [root at tekkaman qemu]# rpm -q libvirt
> libvirt-1.2.9.1-1.fc20.x86_64
> 
> [root at tekkaman qemu]# vdsClient -s 0 getVdsCaps | grep -i merge
> liveMerge = 'true'
> 
> but
> [root at tekkaman qemu]# rpm -q qemu
> qemu-1.6.2-10.fc20.x86_64
> 
> So that tryng live merge it initially start but you get this in vdsm.log:
> libvirtError: unsupported configuration: active commit not supported
> with this QEMU binary

This is expected behavior.  You also need to install the qemu packages from virt-preview to get the feature.


> 2) Another seaparate environment with a dedicated 3.5 engine f20 engine
> and 4 test cases tried
> 
> a) ovirt node installed and put in a dedicated cluster
> latest available seems ovirt-node-iso-3.5.0.ovirt35. 20140912.el6.iso
> from 3.5 rc test days
> 
> At the end of oVirt Node install and activation in engine:
> [root at ovnode01 ~]# vdsClient -s 0 getVdsCaps | grep -i merge
> liveMerge = 'false'
> 
> [root at ovnode01 ~]# rpm -qa libvirt* qemu*
> libvirt- 0.10.2-29 .el6_5.12.x86_64
> libvirt-lock-sanlock- 0.10.2-29 .el6_5. 12.x86_64
> libvirt-python- 0.10.2-29 .el6_5.12.x86_ 64
> qemu-kvm-tools- 0.12.1.2-2.415 .el6_5.14.x86_ 64
> qemu-kvm-rhev- 0.12.1.2-2.415 .el6_5.14.x86_64
> libvirt-client- 0.10.2-29 .el6_5.12.x86_ 64
> qemu-img-rhev- 0.12.1.2-2.415 .el6_5.14.x86_64
> 

Live merge is not supported on EL6, period.  It was simply not possible to backport all of the features into those versions of qemu and libvirt.

> 
> b) f20 + latest updates host installed as OS and then installed from
> webadmin in another cluster
> virt-preview on host it is not enabled so that libvirt/qemu are not ready
> 
> 
> [root at ovnode02 network-scripts]# vdsClient -s 0 getVdsCaps | grep -i merge
> liveMerge = 'false'
> 
> [root at ovnode02 network-scripts]# rpm -qa libvirt* qemu*
> libvirt-daemon-1.1.3.6-2.fc20. x86_64
> libvirt-python-1.1.3.6-2.fc20. x86_64
> libvirt-daemon-config- nwfilter-1.1.3.6-2.fc20.x86_64
> qemu-kvm-1.6.2-10.fc20.x86_64
> qemu-common-1.6.2-10.fc20.x86_ 64
> libvirt-client-1.1.3.6-2.fc20. x86_64
> libvirt-daemon-driver-network- 1.1.3.6-2.fc20.x86_64
> libvirt-daemon-driver- nwfilter-1.1.3.6-2.fc20.x86_64
> libvirt-daemon-driver- interface-1.1.3.6-2.fc20.x86_ 64
> libvirt-daemon-driver-nodedev- 1.1.3.6-2.fc20.x86_64
> libvirt-daemon-driver-secret- 1.1.3.6-2.fc20.x86_64
> qemu-system-x86-1.6.2-10.fc20. x86_64
> libvirt-daemon-kvm-1.1.3.6-2. fc20.x86_64
> qemu-kvm-tools-1.6.2-10.fc20. x86_64
> qemu-img-1.6.2-10.fc20.x86_64
> libvirt-daemon-driver-qemu-1. 1.3.6-2.fc20.x86_64
> libvirt-daemon-driver-storage- 1.1.3.6-2.fc20.x86_64
> libvirt-lock-sanlock-1.1.3.6- 2.fc20.x86_64

Great, this is working as expected.


> c) CentOS 6.6 host + latest updates installed as OS and then installed
> from webadmin in another cluster
> 
> [root at ovnode03 ~]# vdsClient -s 0 getVdsCaps | grep -i merge
> liveMerge = 'false'
> 
> [root at ovnode03 ~]# rpm -qa libvirt* qemu*
> libvirt-python- 0.10.2-46 .el6_6.2.x86_64
> qemu-kvm-rhev-tools- 0.12.1.2-2.415 .el6_5.14. x86_64
> qemu-img-rhev- 0.12.1.2-2.415 .el6_5.14.x86_64
> libvirt-client- 0.10.2-46 .el6_6.2.x86_64
> libvirt- 0.10.2-46 .el6_6.2.x86_64
> qemu-kvm-rhev- 0.12.1.2-2.415 .el6_5.14.x86_64
> libvirt-lock-sanlock- 0.10.2-46 .el6_6.2. x86_64
> 

Also expected due to specific lack of support for el6.

> d) CentOS 7.0 host + latest updates installed as OS and then installed
> from webadmin in another cluster
> 
> [root at ovnode04 ~]# vdsClient -s 0 getVdsCaps | grep -i merge
> liveMerge = 'false'
> 
> [root at ovnode04 ~]# rpm -qa qemu* libvirt*
> qemu-img-rhev-1.5.3-60.el7_0. 2.x86_64
> libvirt-daemon-1.1.1-29.el7_0. 3.x86_64
> libvirt-daemon-driver-storage- 1.1.1-29.el7_0.3.x86_64
> libvirt-daemon-driver-nodedev- 1.1.1-29.el7_0.3.x86_64
> libvirt-daemon-kvm-1.1.1-29. el7_0.3.x86_64
> qemu-kvm-tools-rhev-1.5.3-60. el7_0.2.x86_64
> qemu-kvm-common-rhev-1.5.3-60. el7_0.2.x86_64
> libvirt-client-1.1.1-29.el7_0. 3.x86_64
> libvirt-daemon-driver- nwfilter-1.1.1-29.el7_0.3.x86_ 64
> libvirt-daemon-driver- interface-1.1.1-29.el7_0.3. x86_64
> libvirt-lock-sanlock-1.1.1-29. el7_0.3.x86_64
> libvirt-daemon-config- nwfilter-1.1.1-29.el7_0.3.x86_ 64
> libvirt-daemon-driver-network- 1.1.1-29.el7_0.3.x86_64
> qemu-kvm-rhev-1.5.3-60.el7_0. 2.x86_64
> libvirt-python-1.1.1-29.el7_0. 3.x86_64
> libvirt-daemon-driver-secret- 1.1.1-29.el7_0.3.x86_64
> libvirt-daemon-driver-qemu-1. 1.1-29.el7_0.3.x86_64

el7 will not be supported until 7.1 is released.