[ovs-dev] [RFC] [PATCH] ovn: Support sample action in logical datapath

Valentine Sinitsyn valentine.sinitsyn at gmail.com
Tue Nov 29 14:22:32 UTC 2016


Hi Ben,

On 29.11.2016 05:21, Ben Pfaff wrote:
> On Fri, Oct 14, 2016 at 04:35:46PM +0500, Valentine Sinitsyn wrote:
>> This is a quick attempt to implement sample action at logical port level.The
>> goal is to export IPFIX flows for logical ports, yet it is easy to extend
>> this approach to logical switches as well.
>>
>> Nothing is done to provision OVS instances with required
>> Flow_Sample_Collector_Set and IPFIX entries at this point.
>>
>> Does the approach I take looks sensible? If so, I can add tests and re-send
>> this patch for in-depth review.
>>
>> Many thanks.
>>
>> Signed-off-by: Valentine Sinitsyn <valentine.sinitsyn at gmail.com>
>
> Sorry about the long delay in review.  It's been a difficult month.
No problem.

>
> This is pretty cool!  The integration among OVS and OVN and IPFIX is
> graceful.
>
> The part that worries me is the CMS integration.  Have you actually
> built that integration already (for which CMS)?  I have two concerns.
> First, I'd prefer to see at least one CMS (probably OpenStack) support
> this at or around the time that it goes into OVN.  Second, I have some
> skepticism around the idea that the CMS should configure the
> Flow_Sample_Collector_Set, etc., because OVN doesn't currently require
> the CMS to have any connectivity to OVSDB on each of the hypervisors and
> this would require the CMS to add that support.
I agree that this particular bit is somewhat hacky. We plan to follow 
this route for an in-house CMS we build, but I doubt OpenStack community 
would pickup the idea. What alternatives do you see here? Having 
collector config at south db level doesn't seem clear either. Think I 
want to configure collector at 127.0.0.1:5900 - which localhost does 
this entry refer to?

If the sample() integration looks good, CMS assumptions aside, is there 
a chance to merge it as a stand-alone action? That's true no publicly 
available CMS would use it for a while, but when they decide to, the 
code would already be there. And the code is not dead, as we'll be using 
it as well.

>
> Do you have any thoughts about supporting other monitoring technology
> that OVS supports (e.g. sFlow) using similar techniques?
I haven't targeted any of them specifically, but it doesn't seem to be a 
daunting task. One only need some way to associate sample() instance and 
a sFlow receiver the same way collector_set_id does for IPFIX.

I'd suggest to generalize Flow_Sample_Collector_Set somehow, but we 
agreed configuring things through this table in OVN scenario is 
suboptimal. Any thoughts?

>
> I hope that the long delay does not discourage you from following up.  I
> hope to be more responsive now.
Sure, I'm open for the discussion.

Thanks,
Valentine

>


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