Xen users - Jun 2007 - Automatic Loadbalancing via migration --live

hi,

how can tell Xen, to automatic live migrate VMs, if other hosts has
nothing to do? I red somthing, that it is possible. Do i need such other
 tools like drdb or anything else?

cu denny



_______________________________________________
Xen-users mailing list
Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users

> -----Original Message-----
> From: xen-users-bounces@lists.xensource.com 
> [mailto:xen-users-bounces@lists.xensource.com] On Behalf Of 
> Denny Schierz
> Sent: 01 June 2007 12:22
> To: ''xen-users@lists.xensource.com''
> Subject: [Xen-users] Automatic Loadbalancing via migration --live
> 
> hi,
> 
> how can tell Xen, to automatic live migrate VMs, if other hosts has
> nothing to do? I red somthing, that it is possible. Do i need 
> such other
>  tools like drdb or anything else?
You need to have some sort of tool that figures out when and where to
move the guest, and that tool will use "xm migrate -live some-domain
some-host". 

I think there are some other steps to allow the migration in the first
place - not sure what those are. 

And of course, for this to be at least somewhat meaningfull, you will
need to have the image file(s)/partitions that the guest is using for
disk-storage on a network-accessible place (e.g. a NFS, OCFS, SAN etc)

Note that for HVM guests, this is a new feature to 3.1.0, and I
wouldn''t
expect it to be entirely bug-free at the moment. In fact, I''ve
submitted
three different fixes for problems that are caused by side-effects of
use of the save/restore mechanisms - which is also the code used for
migration. These patces are in the unstable tree. You can certainly
still use the save/restore/migrate functionality, but at some point,
these bugs will probably show their ugly head, unless you understand how
to avoid them (e.g. Save all guests, stop xend, remove xenstore
database, restart xend and restore guests again) - the other one that
will bite is if you try to migrate two guests at the very same moment in
time - once in a while it will fail to create the network interface due
to a race-condition inside the Dom0 Linux kernel (attempting to create
two Tap-interfaces with the same name - the second one failing of
course). 

--
Mats
> 
> cu denny
> 
> 


_______________________________________________
Xen-users mailing list
Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users

hi,


thanks for youre reply :-)

Petersson, Mats schrieb:
> You need to have some sort of tool that figures out when and where to
> move the guest, and that tool will use "xm migrate -live some-domain
> some-host". 
let me tell you, what i mean. On Februar i had a  course on Vmware ESX
and i was very impressed how smooth let the system move the VMs via
VMotion to systems with a low load to balance the power on the network.
You have several options to choose, when Vmware let switch the hosts.
Vmware assign stars, from one, to five. If one VM hast nothing to to, it
has only one star, but if the load is higher and you get 3-5 stars, than
Vmware decide to move the VM to a better Host.
You have the choice, if Vmware does the VMotion automatically, or let
the admin do this.

My hope was, that Xen can this too, but it seems, that i have to do a
lot, to get this feature under Xen.

My testing system reside on a software ISCSI so all VMS can migrate all
ready without any problems :-)

The next step would be to monitoring Xen and the hosts. Most software i
saw are not enough professional enough or need a specialist for
something like nagios. But, Xen is young so, i have to be patient ;-)



cu denny



_______________________________________________
Xen-users mailing list
Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users

There is a reason why VMware ESX costs thousands of dollars per node and
Xen is free.  Once Xen matures with a nice frontend and load balancing,
VMWare will something to worry about.

-----Original Message-----
From: xen-users-bounces@lists.xensource.com
[mailto:xen-users-bounces@lists.xensource.com] On Behalf Of Denny
Schierz
Sent: Friday, June 01, 2007 4:23 PM
To: ''xen-users@lists.xensource.com''
Subject: Re: [Xen-users] Automatic Loadbalancing via migration --live

...
let me tell you, what i mean. On Februar i had a  course on Vmware ESX
and i was very impressed how smooth let the system move the VMs via
VMotion to systems with a low load to balance the power on the network.
...
My hope was, that Xen can this too, but it seems, that i have to do a
lot, to get this feature under Xen.

_______________________________________________
Xen-users mailing list
Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users

hi,


Brent Meshier schrieb:
> There is a reason why VMware ESX costs thousands of dollars per node and
> Xen is free.  Once Xen matures with a nice frontend and load balancing,
> VMWare will something to worry about.
these are my thoughts too, but never give up the hope ;-) I had several
talks with other people who looking for virtualization software and they
are although impress from vmware, but the price ... you can buy islands
from these money. So they looking for other software and Xen has nice
things too.

cu denny



_______________________________________________
Xen-users mailing list
Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users

With a little perl scripting, it wouldn''t be hard to write a load
balancer for Xen.  You would need to track the CPU utilization on each
dom0, and intelligently balance the domU''s across them.  Maybe when I
get some free time in the next few weeks I''ll do just that :)

--Brent

-----Original Message-----
From: xen-users-bounces@lists.xensource.com
[mailto:xen-users-bounces@lists.xensource.com] On Behalf Of Denny
Schierz
Sent: Friday, June 01, 2007 4:40 PM
To: ''xen-users@lists.xensource.com''
Subject: Re: [Xen-users] Automatic Loadbalancing via migration --live

hi,


Brent Meshier schrieb:
> There is a reason why VMware ESX costs thousands of dollars per node 
> and Xen is free.  Once Xen matures with a nice frontend and load 
> balancing, VMWare will something to worry about.
these are my thoughts too, but never give up the hope ;-) I had several
talks with other people who looking for virtualization software and they
are although impress from vmware, but the price ... you can buy islands
from these money. So they looking for other software and Xen has nice
things too.

cu denny


_______________________________________________
Xen-users mailing list
Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users

hi,

Brent Meshier schrieb:
> With a little perl scripting, it wouldn''t be hard to write a load
> balancer for Xen.  You would need to track the CPU utilization on each
> dom0, and intelligently balance the domU''s across them.  Maybe
when I
> get some free time in the next few weeks I''ll do just that :)
that is, why i love the OS community :-)

cu denny



_______________________________________________
Xen-users mailing list
Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users

Brent Meshier wrote:
> With a little perl scripting, it wouldn''t be hard to write a load
> balancer for Xen.  You would need to track the CPU utilization on each
> dom0, and intelligently balance the domU''s across them.  Maybe
when I
> get some free time in the next few weeks I''ll do just that :)
>
> --Brent
>   
You can use nagios (or something like) to monitor Dom0 and DomU. when 
you have a performance (or failure)  issue you can move the DomU to 
other Dom0 (use the external commands in the nagios server).

(if it will be in a mission critical env - you may need an High 
Availability service for the nagios)


It is not just for load balancing, you can use it for High Availability  
of VM''s, DRP, BCP etc.


We tested a few configuration in our lab in the last week , looks good.


- doron
> -----Original Message-----
> From: xen-users-bounces@lists.xensource.com
> [mailto:xen-users-bounces@lists.xensource.com] On Behalf Of Denny
> Schierz
> Sent: Friday, June 01, 2007 4:40 PM
> To: ''xen-users@lists.xensource.com''
> Subject: Re: [Xen-users] Automatic Loadbalancing via migration --live
>
> hi,
>
>
> Brent Meshier schrieb:
>   
>> There is a reason why VMware ESX costs thousands of dollars per node 
>> and Xen is free.  Once Xen matures with a nice frontend and load 
>> balancing, VMWare will something to worry about.
>>     
>
> these are my thoughts too, but never give up the hope ;-) I had several
> talks with other people who looking for virtualization software and they
> are although impress from vmware, but the price ... you can buy islands
> from these money. So they looking for other software and Xen has nice
> things too.
>
> cu denny
>
>
> _______________________________________________
> Xen-users mailing list
> Xen-users@lists.xensource.com
> http://lists.xensource.com/xen-users
>   


_______________________________________________
Xen-users mailing list
Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users

Nagios is an interesting idea, and since it only takes a single command
line to migrate a domU, I guess it would work well.  My thoughts are
load balancing Xen go beyond moving a high load domU to a load load
dom0.  A couple factors to consider are how long a domU sustains high
CPU usage before it warrants moving and historical CPU usage of the
potential dom0 target.  You don''t want your cluster bouncing
domU''s
around every minute trying to achieve a perfect balance.

 

--Brent

 

From: xen-users-bounces@lists.xensource.com
[mailto:xen-users-bounces@lists.xensource.com] On Behalf Of Ofek Doron
[Penguin IT]
Sent: Friday, June 01, 2007 7:44 PM
To: xen-users@lists.xensource.com
Subject: Re: [Xen-users] Automatic Loadbalancing via migration --live

 

 

You can use nagios (or something like) to monitor Dom0 and DomU. when
you have a performance (or failure)  issue you can move the DomU to
other Dom0 (use the external commands in the nagios server).

(if it will be in a mission critical env - you may need an High
Availability service for the nagios)

 

It is not just for load balancing, you can use it for High Availability
of VM''s, DRP, BCP etc. 

 

We tested a few configuration in our lab in the last week , looks good. 

 

- doron 

 



_______________________________________________
Xen-users mailing list
Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users

> -----Original Message-----
> From: xen-users-bounces@lists.xensource.com 
> [mailto:xen-users-bounces@lists.xensource.com] On Behalf Of 
> Denny Schierz
> Sent: 01 June 2007 22:09
> To: ''xen-users@lists.xensource.com''
> Subject: Re: [Xen-users] Automatic Loadbalancing via migration --live
> 
> hi,
> 
> Brent Meshier schrieb:
> > With a little perl scripting, it wouldn''t be hard to write a
load
> > balancer for Xen.  You would need to track the CPU 
> utilization on each
> > dom0, and intelligently balance the domU''s across them.  
> Maybe when I
> > get some free time in the next few weeks I''ll do just that :)
> 
> that is, why i love the OS community :-)
May I just suggest that you consider using Python instead of Perl - this
is not an attempt to create a "Perl vs. Python" war [there''s
plenty
enough discussion elsewere on which is better for what reason], rather
that Python is already necessary to run Xen, so why not stick to the
same language that it''s already using? 

It''s probably also easier to hack the Python scripts into the existing
Xen project. 

By the way, I''d have a look at the Xen "products"
(XenExpress, XenServer
and XenEnterprise - all of which are exactly the same binaries, but with
different (enforced!) restrictions in the licensing), I think there may
be automatic load-balancing already in this product. XenExpress is
available at no-cost, but limited to 4 domains and 4GB per machine. 

--
Mats
> 
> cu denny
> 
> 


_______________________________________________
Xen-users mailing list
Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users