[one-users] deployment of certain vm's to different hosts

[Mark Wagner]

I'm interested in this idea as well.  Without modifying the ONE code 
here is how it could be accomplished by extending the IM MAD and using 
the "REQUIREMENTS" section of a VM template to exclude a host that is 
already running a guest of the same type.

How to go about it is the somewhat kludgey part. The IM MAD scripts are 
run on the host; as far as I can tell from the host it is impossible to 
easily see the names of the guests running on it. The best idea I could 
think of would be to ssh back to the FE and run "onevm list | grep 
$HOST" and process that.

Next, how do you group the guests? Assuming the guests have the naming 
scheme of <type>NNN you could group them by removing the NNN. Another 
way to do it would be to do a onevm show on each guest but that may be 
too resource intensive.

Putting this all together, here is the IM MAD script:

#!/bin/sh

VM_HOST=`hostname`
FE=onefe

GUEST_TYPES="`ssh $FE onevm list --list NAME,HOST | grep $VM_HOST | awk 
'{ print $1 }' | sed 's/[0-9]*$//g' | sort -u`"
GUEST_TYPES=":`echo $GUEST_TYPES | sed 's/ /:/g'`:"

echo "GUEST_TYPES=\"$GUEST_TYPES\""

For example type "ntp" you'd put in the template

REQUIREMENTS = "GUEST_TYPES != \"*:ntp:*\""

(I haven't tested this at all).

On 12/11/2012 10:47 AM, Gary S. Cuozzo wrote:
> Hello,
> We have certain vm's which are related and provide redundancy and/or 
> failover to each other.  Ideally, we'd like to avoid the situation 
> where these vm's run on the same host machine.  Is there a way to 
> configure the scheduler so it would know to rule out a host if another 
> related vm was already running there?
>
> If there is no feature in ONE already, what I'm thinking is having an 
> attribute that can be set in the vm template which could be used to 
> group vm's together.  Then, the scheduler can just check to see if a 
> vm that is part of the same group(s) is already running and rule that 
> host out if there is.  It could also optionally override the attribute 
> if it could not find a 'unique' host to deploy on (for example, 
> multiple hosts are unavailable and there are not enough resource to 
> deploy to unique hosts).
>
> Please let me know if a feature already exists or if my idea is worth 
> pursuing.
>
> Cheers,
> gary
>
>
>
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-- 
Mark Wagner | mwagner at intelius.com
System Administrator | Intelius Inc.

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