Is there a reason that ONE can't call a TM script with the source host, dest 
host, vm template, etc. when the migrate command is executed? 

While ONE can't orchestrate the migration, it can at least notify the TM of the 
migration in advance. That would allow me to grab the info I need from the 
template and fire off the login or rescan on the dest host. ONE has got to know 
this info in order to even notify libvirt/KVM to do the migration. So just call 
a TM script before issuing the libvirt command and abort if the script returns 
error. 

Logout is not as critical to me. Worst case I have some hosts which iSCSI 
sessions which are not in use. The ideal scenario would be to be able to have 
some sort of TM script that gets called after ONE detects successful migration, 
but I could work around that on my own if it were not the case. 

----- Original Message -----

From: "Ruben S. Montero" <[email protected]> 
To: "Gary S. Cuozzo" <[email protected]> 
Cc: [email protected] 
Sent: Thursday, August 16, 2012 11:28:27 AM 
Subject: Re: [one-users] iSCSI recipe 

Note that OpenNebula cannot orchestrate the two libvirt/KVM hypervisors doing 
the migration. When the first host is ready to stop running the VM (memory has 
been sent to the second hypervisor, etc..) it executes the hook (logout from 
the iSCSI server) and just right before starting rhe VM in the second host the 
hook (login in the iSCSI server) is run. There is nothing we can do to hook in 
that process. 


We could however, include such scripts as part of the TM, distribute them in 
the hosts, and put them in the right places... 




Cheers 











On Thu, Aug 16, 2012 at 1:48 PM, Gary S. Cuozzo < [email protected] > wrote: 




Thanks. While I understand that the login/logout needs to happen on the host 
systems, I think that if ONE had it's own hook or, better IMO, a TM script that 
could be called before/after migration, the functionality could be contained 
within the drivers themselves. Then I could just take my code (which is now 
sprinkled across several host machines) and put it in the TM where I think it 
better fits. My DS/TM already make remote calls via SSH to the SAN & vm hosts, 
so this would still fit the model pretty nicely. 

I seem to remember that if the similar events for non-persistent images were 
called for persistent ones, I would be able to accomplish what I want. 

Let me know your thoughts. 

Thanks, 
gary 




From: "Ruben S. Montero" < [email protected] > 
To: "Gary S. Cuozzo" < [email protected] > 
Cc: [email protected] 
Sent: Thursday, August 16, 2012 5:55:57 AM 
Subject: Re: [one-users] iSCSI recipe 

Hi 


For live-migrations the supported procedure is the libvirt hook, note that live 
migrations requires a close synchronization between the image movements, memory 
movements and the hypervisors. OpenNebula cannot perform the login/logout from 
the iSCSI sessions there. Cold migrations are handled by opennebula as part of 
the save and restore commands. 


Cheers 


Ruben 


On Sun, Aug 12, 2012 at 4:41 AM, Gary S. Cuozzo < [email protected] > wrote: 

<blockquote>


Hello, 



<blockquote>


<blockquote>
* Each host needs to attach to all iSCSI targets that are needed by 
guests running on the host. It's not entirely clear to me if ONE handles 
all that or not (assuming it does). 



ONE handles this by login/logout in an iSCSI session as needed 


</blockquote>

My iSCSI setup uses a target for each virtual server, and multiple LUN's per 
target (if the server has multiple disks). I developed a custom driver for it. 
I don't know if I have a shortcoming in my driver, or maybe a config issue on 
ONE, but I found that ONE did NOT handle the login/logout on the host machines. 
It was fine for the initial setup & deployment of the vm, but live migrations 
did not cause my driver to initiate a login on the receiving host and a logout 
on the transferring host. 

I ended up having to write a libvirt hook which scanned for new targets to log 
them in. It also rescanned all current targets to check if they had new LUN's 
attached to them. It works well and my vm's migrate just fine, but I would 
prefer to have all this handled within ONE. 

What is the script that ONE calls in order to initiate the logins/logouts as 
vm's migrate? 

Cheers, 
gary 



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-- 
Ruben S. Montero, PhD 
Project co-Lead and Chief Architect 
OpenNebula - The Open Source Solution for Data Center Virtualization 
www.OpenNebula.org | [email protected] | @OpenNebula 


</blockquote>


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</blockquote>




-- 
Ruben S. Montero, PhD 
Project co-Lead and Chief Architect 
OpenNebula - The Open Source Solution for Data Center Virtualization 
www.OpenNebula.org | [email protected] | @OpenNebula 

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