[openstack-dev] [neutron][L3] VM Scheduling v/s Network as input any consideration ?

jcsf jcsf31459 at gmail.com
Fri May 30 08:47:18 UTC 2014


Sylvain,

 

Thank you for the background – I will educate myself on this work.

 

Thanks,

John

 

 

From: Sylvain Bauza [mailto:sbauza at redhat.com] 
Sent: Friday, May 30, 2014 11:31 AM
To: OpenStack Development Mailing List (not for usage questions)
Cc: jcsf; 'Carl Baldwin'; 'A, Keshava'
Subject: Re: [openstack-dev] [neutron][L3] VM Scheduling v/s Network as
input any consideration ?

 

Le 30/05/2014 10:06, jcsf a écrit :

Carl,

 

A new routing protocol is certainly of great interest.   Are you working
with IETF or can you share more here?

 

WRT:Nova Schedule - There still are requirements for the Schedule to taking
into consideration network as a resource.   My focus is to figure out how to
add network capabilities to the Scheduler’s algorithm while still
maintaining clean separation of concerns between Nova and Neutron.   We
wouldn’t want to get back into the nova-network situation.  

 

John


As it was previously mentioned, there are already different kinds of
grouping for VMs in Nova that probably don't require to add new
network-specific features :
 - aggregates and user-facing AZs allow to define a common set of
capabilities for physical hosts upon which you can boot VMs
 - ServerGroups with Affinity/Anti-Affinity filters allow you to enforce a
certain level of network proximity for VMs


Once that said, there is also another effort of forking the Nova Scheduler
code into a separate project so that cross-projects scheduling could happen
(and consequently Neutron could use it). This project is planned to be
delivered by K release, and will be called Gantt.


So, could you please mention which features do you need for Nova, so we
could discuss that here before issuing a spec ?

-Sylvain







 

 

From: Carl Baldwin [mailto:carl at ecbaldwin.net] 
Sent: Friday, May 30, 2014 12:05 AM
To: A, Keshava
Cc: jcsf31459 at gmail.com; Armando M.; OpenStack Development Mailing List (not
for usage questions); Kyle Mestery
Subject: Re: [openstack-dev] [neutron][L3] VM Scheduling v/s Network as
input any consideration ?

 

Keshava,

 

How much of a problem is routing prefix fragmentation for you?
Fragmentation causes routing table bloat and may reduce the performance of
the routing table.  It also increases the amount of information traded by
the routing protocol.  Which aspect(s) is (are) affecting you?  Can you
quantify this effect?

 

A major motivation for my interest in employing a dynamic routing protocol
within a datacenter is to enable IP mobility so that I don't need to worry
about doing things like scheduling instances based on their IP addresses.
Also, I believe that it can make floating ips more "floaty" so that they can
cross network boundaries without having to statically configure routers.

 

To get this mobility, it seems inevitable to accept the fragmentation in the
routing prefixes.  This level of fragmentation would be contained to a
well-defined scope, like within a datacenter.  Is it your opinion that
trading off fragmentation for mobility a bad trade-off?  Maybe it depends on
the capabilities of the TOR switches and routers that you have.  Maybe
others can chime in here.

 

Carl

 

On Wed, May 28, 2014 at 10:11 PM, A, Keshava <keshava.a at hp.com> wrote:

Hi,

Motivation behind this  requirement is “ to achieve VM prefix aggregation
using routing protocol ( BGP/OSPF)”.

So that prefix advertised from cloud to upstream will be aggregated.

 

I do not have idea how the current scheduler is implemented. 

But schedule to  maintain some kind of the ‘Network to Node mapping to VM”
..

Based on that mapping to if any new VM  getting hosted to give prefix in
those Nodes based one input preference.

 

It will be great help us from routing side if this is available in the
infrastructure.

I am available for review/technical discussion/meeting. 

 

 

Thanks & regards,

Keshava.A

 

From: jcsf31459 at gmail.com [mailto:jcsf31459 at gmail.com] 
Sent: Thursday, May 29, 2014 9:14 AM
To: openstack-dev at lists.openstack.org; Carl Baldwin; Kyle Mestery; OpenStack
Development Mailing List (not for usage questions)
Subject: Re: [openstack-dev] [neutron][L3] VM Scheduling v/s Network as
input any consideration ?

 

Hi keshava,

 

This is an area that I am interested in.   I'd be happy to collaborate with
you on a blueprint.    This would require enhancements to the scheduler as
you suggested.   

 

There are a number of uses cases for this.  

  

 

‎John. 

 

Sent from my  smartphone.


From: A, Keshava‎

Sent: Tuesday, May 27, 2014 10:58 AM

To: Carl Baldwin; Kyle Mestery; OpenStack Development Mailing List (not for
usage questions)

Reply To: OpenStack Development Mailing List (not for usage questions)

Subject: [openstack-dev] [neutron][L3] VM Scheduling v/s Network as input
any consideration ?

 

Hi,

I have one of the basic question about the Nova Scheduler in the following
below scenario.

Whenever a new VM to be hosted is there any consideration of network
attributes ? 

Example let us say all the VMs with 10.1.x is under TOR-1, and 20.1.xy are
under TOR-2.

A new CN nodes is inserted under TOR-2 and at same time a new  tenant VM
needs to be  hosted for 10.1.xa network.

 

Then is it possible to mandate the new VM(10.1.xa)   to hosted under TOR-1
instead of it got scheduled under TOR-2 ( where there CN-23 is completely
free from resource perspective ) ? 

This is required to achieve prefix/route aggregation and to avoid network
broadcast (incase if they are scattered across different TOR/Switch) ? 

 

 

 



 

Thanks & regards,

Keshava.A

 

 

 






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