cloudstack-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Ron Wheeler <rwhee...@artifact-software.com>
Subject Re: [DISCUSS] Why we MARK packets?
Date Fri, 20 Apr 2018 15:23:41 GMT
https://markandruth.co.uk/2016/08/08/testing-the-performance-of-the-linux-firewall
Does not directly address marking but does benchmark a number of 
iptables filtering tasks which may give some insight into the 
performance implications of using iptables for routing and filtering.

https://www.digitalocean.com/community/tutorials/a-deep-dive-into-iptables-and-netfilter-architecture
A nice article on iptables. No performance info but a good read for 
anyone who needs to tackle routing and marking.

  https://www.markusschade.com/papers/firewall.pdf
Has some performance info and a discussion about the host limit with MARK.

I am a bit skeptical that MARK adds a lot of overhead but this is only 
based on the belief that CPUs are orders of magnitude faster than networks.
The decision process on entry and exit are both pretty simple and 
depending on the implementation of the internal table should not take a 
lot of memory of CPU to do the table lookups

I did not read all 60,400 links returned by Google but in the ones that 
I did read did not warn of any big problem with performance using MARK.

I use a simple static MARK configuration in my firewall to solve a 
routing problem but the performance requirements are not relevant to an 
datacentre with hundreds of CPUs and hundreds of entries in the MARK 
routing map.

I hope that this helps.

Ron


On 20/04/2018 9:04 AM, Rohit Yadav wrote:
> Thanks Jayapal. I don't have any comparative study yet, but I'll explore this in future
if we can get away without marking (mangling) packets which is generally an expensive task.
>
>
> - Rohit
>
> <https://cloudstack.apache.org>
>
>
>
> ________________________________
> From: Jayapal Uradi <jayapal.uradi@accelerite.com>
> Sent: Thursday, April 19, 2018 10:33:25 AM
> To: dev@cloudstack.apache.org
> Cc: users@cloudstack.apache.org
> Subject: Re: [DISCUSS] Why we MARK packets?
>
> Rohit,
>
> My comments inline.
>
>
> rohit.yadav@shapeblue.com
> www.shapeblue.com
> 53 Chandos Place, Covent Garden, London  WC2N 4HSUK
> @shapeblue
>    
>   
>
> On Apr 19, 2018, at 1:52 AM, Rohit Yadav <rohit.yadav@shapeblue.com<mailto:rohit.yadav@shapeblue.com>>
wrote:
>
> Nevermind, found the use of custom routing tables. In case someone want to refer, hints
are here:
>
> https://github.com/apache/cloudstack/pull/2514#issuecomment-382510915
>
>
> Jayapal and others - I've another one, is there a way to do routing without marking packets
at all, even in case of VRs with additional public interfaces?
>
> AFAIK marking is the only way to do it.
> Do you have any performance numbers with and without mark rules.
>
> - Rohit
>
> <https://cloudstack.apache.org<https://cloudstack.apache.org/>>
>
>
>
> ________________________________
> From: Rohit Yadav <rohit.yadav@shapeblue.com<mailto:rohit.yadav@shapeblue.com>>
> Sent: Wednesday, April 18, 2018 10:39:02 PM
> To: dev@cloudstack.apache.org<mailto:dev@cloudstack.apache.org>; users@cloudstack.apache.org<mailto:users@cloudstack.apache.org>
> Subject: [DISCUSS] Why we MARK packets?
>
> All,
>
>
> I could not find any history around 'why' we MARK or CONNMARK packets in mangle table
in VRs? I found an issue in case of VPCs where `MARK` iptable rules failed hair-pin nat (as
described in this PR: https://github.com/apache/cloudstack/pull/2514)
>
>
> The valid usage I found was wrt VPN_STATS, however, the usage is not exported at all,
it is commented:
>
> https://github.com/apache/cloudstack/blob/master/systemvm/debian/opt/cloud/bin/vpc_netusage.sh#L141
>
>
> Other than for debugging purposes in the VR, marking packets and connections I could
not find any valid use. Please do share if you're using marked packets (such as VPN ones etc)
outside of VR scope?
>
>
> I propose we remove MARK on packets which is cpu intensive and slows the traffic (a bit),
instead CONNMARK can still be used to mark connections and debug VRs without actually changing
the packet marking permanently. Thoughts?
>
>
> - Rohit
>
> <https://cloudstack.apache.org>
>
>
>
> rohit.yadav@shapeblue.com<mailto:rohit.yadav@shapeblue.com>
> www.shapeblue.com<http://www.shapeblue.com/><http://www.shapeblue.com<http://www.shapeblue.com/>>
> 53 Chandos Place, Covent Garden, London  WC2N 4HSUK
> @shapeblue
>
>
>
>
> rohit.yadav@shapeblue.com<mailto:rohit.yadav@shapeblue.com>
> www.shapeblue.com<http://www.shapeblue.com/>
> 53 Chandos Place, Covent Garden, London  WC2N 4HSUK
> @shapeblue
>
> DISCLAIMER
> ==========
> This e-mail may contain privileged and confidential information which is the property
of Accelerite, a Persistent Systems business. It is intended only for the use of the individual
or entity to which it is addressed. If you are not the intended recipient, you are not authorized
to read, retain, copy, print, distribute or use this message. If you have received this communication
in error, please notify the sender and delete all copies of this message. Accelerite, a Persistent
Systems business does not accept any liability for virus infected mails.


-- 
Ron Wheeler
President
Artifact Software Inc
email: rwheeler@artifact-software.com
skype: ronaldmwheeler
phone: 866-970-2435, ext 102


Mime
View raw message