[sheepdog-users] Sheepdog 0.9 missing live migration feature

[Liu Yuan]

On Mon, Mar 02, 2015 at 09:35:13PM +0100, Walid Moghrabi wrote:
> 
> Hi, 
> 
> 
> I just updated to 0.9.1 which apparently fixes many snapshot related issues I got but now, it is impossible to live migrate virtual machines anymore. 
> I know this feature is not supported by 0.9, this has been announced and discussed many times but this is very frustrating because this is a must feature especially when used in virtualization clustered stack such as ProxMox or OpenStack. 
> This is even more frustrating that before 0.9, this was working and pretty well I must say so I don't know why this feature has been removed. 
> 

It was not removed, but was broken by Sheepdog's lock mechanism.

> 
> Are there any plan in a near future to support live migration again ? 

We introduced an option to disable the lock mechanism as default, meaning that
the live migration feature would work as before.

Following patch in the master branch fixes the problem:

commit aaa80dc785707f32e2c3818fd5edf74ee05e5144
Author: Wang Zhengyong <wangzhengyong at cmss.chinamobile.com>
Date:   Thu Feb 12 00:53:25 2015 -0800

    Make the vdi lock mechanism optional
    
    Current sheepdog driver will send LOCK_VDI/RELEASE_VDI ops,
    while start/stop QEMU VM with sheepdog protocol, this mechanism
    will lead qemu-img/qemu-io report error when the sheepdog VDI is locking
    
    To keep backward compatiblity, this patch modify the functionality
    that make the vdi lock mechanism optional(with --lock opention),
    default VDI lock is disabled
    
    Enable VDI lock:
    e.g. dog cluster format --lock
    
    Cc: Hitoshi Mitake <mitake.hitoshi at gmail.com>
    Signed-off-by: Wang Zhengyong <wangzhengyong at cmss.chinamobile.com>
    Signed-off-by: Hitoshi Mitake <mitake.hitoshi at lab.ntt.co.jp>

=================================================

You can either try master branch to test it.

Hitosh, it would be great if you can backport this patch to 0.9.x.

Thanks,
Yuan