Re: [Xen-users] Failover

["Matthijs ter Woord" <matthijsterwoord@xxxxxxxxx>]

Isn't there a way to set up a drbd partition which contians the vm harddrive
images, setting files etc, and somehow detect a failure of node 1 so node 2
can start booting?


Greets,

Matthijs ter Woord


----- Original Message -----
From: "Chris de Vidal" <cdevidal@xxxxxxxxx>
To: "Matthijs ter Woord" <matthijsterwoord@xxxxxxxxx>;
<xen-users@xxxxxxxxxxxxxxxxxxx>
Sent: Sunday, August 14, 2005 3:01 PM
Subject: Re: [Xen-users] Failover


> --- Matthijs ter Woord <matthijsterwoord@xxxxxxxxx> wrote:
> > Is it possible to eliminate the possibility of a Xen host failure due to
> > hardware failure (ie. failover clustering)?
>
> I'm no Xen expert but from what I can tell you can't to high-availability
with
> the Xen kernel itself.
>
> However, if you think about it, there is very little difference between
domU
> virtual machines and real machines.  You can easily do high-availability
on
> domU guests between two physical Xen hosts.  Run all of your services on
domUs
> and use something like UltraMonkey, regular LVS, Heartbeat, OpenSSI
(assuming
> it works with the domU kernel patches), or some other HA solution giving
you
> failover clustering.
>
> The difference between this and a real cluster is only that Xen is running
> below the virtual machines; very little is different.  They only add a
thin
> layer of separation.
>
>
> So for example if your poison of choice is Heartbeat and you want to make
> Apache highly available, you do this:
> Apache1         Apache2
>   |               |
>   +---Heartbeat---+
>   |               |
> DomU1           DomU2
> virtual         virtual
> machine         machine
>   |               |
> Xen1            Xen2
> kernel          kernel
>   |               |
> Node1           Node2
> hardware        hardware
>
> A real cluster would look like this:
> Apache1         Apache2
>   |               |
>   +---Heartbeat---+
>   |               |
> Node1           Node2
> hardware        hardware
>
>
> Very little difference.
>
> Hope that helps!
>
> CD
>
> You have to face a Holy God on Judgment Day. He sees lust as adultery
(Matt. 5:28) and hatred as murder (1 John 3:15). Will you be guilty?
>
> Jesus took your punishment on the cross, and rose again defeating death,
to save you from Hell. Repent (Luke 13:5) and trust in Him today.
>
> NeedGod.com



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