[Users] How to force VM's to run on different hosts?

[Doron Fediuck]

----- Original Message -----
> From: "Itamar Heim" <iheim at redhat.com>
> To: "Maxim Burgerhout" <maxim at wzzrd.com>
> Cc: users at ovirt.org, "Laszlo Hornyak" <lhornyak at redhat.com>, "Doron Fediuck" <dfediuck at redhat.com>
> Sent: Tuesday, July 31, 2012 10:36:45 PM
> Subject: Re: [Users] How to force VM's to run on different hosts?
> 
> On 07/31/2012 10:20 PM, Maxim Burgerhout wrote:
> > Nice, thanks for the info. Can you give a hint of a time frame for
> > the
> > implementation? I'm not asking for dates or even version numbers,
> > just
> > something along the lines of 'short term', 'mid term', etc.
> 
> I'd go with mid-term.
> (there is a POC patch for integrating drools which would allow you to
> write your own scheduling policies for something like that)
> http://gerrit.ovirt.org/#/c/6574/
> 
> several thoughts here:
> 1. need to add positive/negative affinity fields to VM entity.
> 2. make the scheduling logic a supported interface for pluggable
> implementations
> 3. implement the drool implementation as a pluggable implementation.
> 4. support affinity based scheduling
> 
> #2 would allow someone to write their own scheduling logic in java
> code
> (well, maybe java wrapping/calling some other language).
> 
> #3 would allow someone to write their own scheduling logic using rule
> based language with drools.
> 
> #4 would mean you wouldn't need #2-#3 for this specific feature.
> 
> 

Note that the POC Itamar referred to works with Planner,
which is really nice, but will change in the future. That
said, I agree that VM affinity and negative affinity is
definitely in oVirt's roadmap.

> >
> > Regards,
> >
> >
> > Maxim Burgerhout
> > maxim at wzzrd.com <mailto:maxim at wzzrd.com>
> > ----------------
> > EB11 5E56 E648 9D99 E8EF 05FB C513 6FD4 1302 B48A
> >
> >
> >
> >
> > On Tue, Jul 31, 2012 at 3:19 PM, Itamar Heim <iheim at redhat.com
> > <mailto:iheim at redhat.com>> wrote:
> >
> >     On 07/31/2012 04:07 PM, Maxim Burgerhout wrote:
> >
> >         Hi,
> >
> >         Can someone tell me whether setting positive and negative
> >         VM
> >         affinity
> >         rules will be at all possible with oVirt at some point in
> >         time,
> >         i.e. is
> >         this on the roadmap?
> >
> >
> >     it is.
> >
> >
> >         I need to be able to tell VM's to run on different hosts,
> >         spread
> >         them
> >         around, so to speak. For example, domain controllers would
> >         be
> >         better off
> >         running on as many different hypervisors as possible, the
> >         way I
> >         see it.
> >         That way, the failure of a single hypervisor has minimal
> >         impact
> >         on the
> >         infrastructure. I know there is a feature to pin VM's to a
> >         single
> >         hypervisor, but that's not quite the same. I would like to
> >         group the
> >         domain controllers and then tell them not to run on the
> >         same host as
> >         other members of that group as much as possible.
> >
> >         The other way around would be nice as well: have several
> >         VM's
> >         run on the
> >         same hardware. For example, a three tiered web application
> >         would
> >         probably perform better if the VM's are all on the same
> >         hypervisor. I
> >         know I could pin them all to the same hypervisor, but
> >         still:
> >         that's not
> >         quite the same. I want to be able to group the web app VM's
> >         and tell
> >         them to try to run on the same hypervisors as the other
> >         members
> >         of the
> >         group, so they can move to another hypervisor as a group if
> >         the
> >         need arises.
> >
> >         Apologies if this has been asked before or documented in
> >         some
> >         place I
> >         haven't looked yet.
> >
> >
> >     two ways for you to do this today:
> >     1. prefer/pin these VMs to different host
> >     2. use two clusters and put them in different ones
> >
> >         Regards,
> >
> >         Maxim Burgerhout<mailto:maxim at wzzrd.__com
> >         <mailto:maxim at wzzrd.com>>
> >
> >
> >
> >
> >
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> >
> >
> >
> >
> 
> 
>