Open Stack

Hi Brian,

You're right It could be easier with your approach to get and keep the traffic counters.

I will add a new method to get the details of traffic counters of a chain.
https://review.openstack.org/35624

Thoughts?

Regards,

Sylvain.

----- Original Message -----
From: "Sylvain Afchain" <sylvain.afchain at enovance.com>
To: "Brian Haley" <brian.haley at hp.com>
Cc: openstack-dev at lists.openstack.org
Sent: Thursday, July 11, 2013 11:19:39 AM
Subject: Re: Change in openstack/neutron[master]: Add method to get iptables traffic counters

Hi Brian,

First thanks for the reviews and your detailed email.

Second I will update the blueprint specs. as soon as possible, but for example it will look like that:

Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
    pkts      bytes target     prot opt in     out     source               destination         
       55       245 metering-r-aef1456343  all  --  *      *       0.0.0.0/0            0.0.0.0/0   /* jump to rules the label aef1456343 */        
       55       245 metering-r-badf566782  all  --  *      *       0.0.0.0/0            0.0.0.0/0           

Chain metering-l-aef1456343 (1 references)	/* the chain for the label aef1456343 */
    pkts      bytes target     prot opt in     out     source               destination         

Chain metering-l-badf566782 (1 references)	/* the chain for the label badf566782 */
    pkts      bytes target     prot opt in     out     source               destination         

Chain metering-r-aef1456343 (1 references)
    pkts      bytes target     prot opt in     out     source               destination         
       20     100 RETURN     all  --  *      *       0.0.0.0/0           !10.0.0.0/24      /* don't want to count this traffic */   
       0        0 RETURN     all  --  *      *       0.0.0.0/0           !20.0.0.0/24      /* don't want to count this traffic */   
       25      145 metering-l-aef1456343  all  --  *      *       0.0.0.0/0            0.0.0.0/0	/* count the remaining traffic */         

Chain metering-r-badf566782 (1 references)
    pkts      bytes target     prot opt in     out     source               destination         
       0        0 metering-l-badf56678  all  --  *      *       0.0.0.0/0            30.0.0.0/24 /* want to count only this */


Of course the in/out interfaces will be set in order to get the ingress or the egress traffic.

I agree with you I could add a single rule to the chain of the label and get the traffic of the first entry, though I found this approach less generic. 
I mean, to be forced to add a rule at the top of a chain to get its traffic. My approach is I don't want the counters of a specific rule but I want to count
the traffic going through the chain.

Thoughts?

Regards,

Sylvain.

----- Original Message -----
From: "Brian Haley" <brian.haley at hp.com>
To: "sylvain afchain" <sylvain.afchain at enovance.com>
Cc: openstack-dev at lists.openstack.org
Sent: Thursday, July 11, 2013 2:30:24 AM
Subject: Re: Change in openstack/neutron[master]: Add method to get iptables traffic counters

On 07/08/2013 01:10 PM, Sylvain Afchain (Code Review) wrote:
> Sylvain Afchain has posted comments on this change.
> 
> Change subject: Add method to get iptables traffic counters
<snip>
> --
> To view, visit https://review.openstack.org/35624

Hi Sylvain,

Instead of trying to ask questions directly in the review itself (since it will mess-up formatting) I'll just send this to you and the list since I had some questions on the traffic counter changes you've been doing.

First, thanks for working on this, it's definitely something I'm interested in, and I'm trying to review all your changes.

Second, do you have more than just the short description from the blueprint for how the iptables chains/rules will look like when created?  I'm still a little confused with this change (above) and how it's matching chains to get packet/byte statistics.  I'm thinking it can be done within a single chain so that you can do an 'iptables -L $chain' call to get just what you need, instead of parsing the entire table.

For example, I did something similar in Nova (out of tree), and it used a single chain per-VM, such that you could get it's statistics with a single iptables call like:

(sorry if this wraps)
$ sudo iptables -t mangle -L nova-meter-output-91 -n -v -x [-Z]
Chain nova-meter-output-91 (1 references)
    pkts      bytes target     prot opt in     out     source               destination         
  805210 247931149            all  --  *      *       0.0.0.0/0            0.0.0.0/0        /* inst-91 packets transmitted total */ 
   15510   964648             all  --  *      *       0.0.0.0/0            x.y.0.0/16
   21282  3075403             all  --  *      *       0.0.0.0/0            x.z.0.0/16
   [...]

None of the rules in the chain has a jump target, so they simply count packets/bytes as they pass through, and the chain is called from a single location based on IP address, so in iptables-save format it looks like this:

-A nova-meter-output -s $my_ip/32 -i bridge1 -j nova-meter-output-91 
-A nova-meter-output-91 -m comment --comment "inst-91 packets transmitted total"
-A nova-meter-output-91 -d x.y.0.0/16
-A nova-meter-output-91 -d x.z.0.0/16
[...]

Obviously with Neutron, and doing this at the router egress, things change, but I think it could still be done in a single OUTPUT chain in the filter table.

Thoughts?

-Brian