VIMAGE, epair/if_bridge or netgraph?

[dteske at FreeBSD.org]

> -----Original Message-----
> From: owner-freebsd-virtualization at freebsd.org [mailto:owner-freebsd-
> virtualization at freebsd.org] On Behalf Of Palle Girgensohn
> Sent: Monday, June 11, 2012 2:37 PM
> To: freebsd-virtualization at FreeBSD.org
> Subject: VIMAGE, epair/if_bridge or netgraph?
> 
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
> 
> Hi,
> 
> I'm updating some jail servers, and want to use VIMAGE. Compiled it into the
> kernel, learned the hard way not to even include PF in the same kernel [1],
> so now it works quite well.
> 
> I am setting up many similar jails, some for testing, some for production. The
> applications are web servers, som tomcat+apache's, and some other
> standard type of services like email and ldap, simple stuff.
> I need no fancy network control, I just need it to work. For each jail there are
> two interfaces, one public, connected to a software bridge (if_bridge or
> ng_bridge) acting as a switch, and one internal, for maintenance, connected
> to a different software bridge. To each software bridge, I connect a physical
> external interface from the jail host.
> 
> I am trying to decide whether to use epair and if_bridge, or to use netgraph.
> For netgraph, there is a nice package at DruidBSD [3]. When I found that, I
> had already rewritten the standard jail script, using the
> v2 patches from polymorf [4]. They work equally fine for my purpose.
> 
> So now I need to know which scales best, is there a difference in
> performance or stability between netgraph and epair/if_bridge?
> 
> Cheers,
> Palle
> 
> 
> [1] http://forums.freebsd.org/showthread.php?t=31765
> 
> [2] http://forums.freebsd.org/showthread.php?t=31949
> 
> [3] http://druidbsd.sourceforge.net/vimage.shtml
> 
> [4] http://wiki.polymorf.fr/index.php?title=Howto:FreeBSD_jail_vnet

[Devin Teske] 

Never saw a reply to this and I'm locating round-tuits to tackle e-mails
that I've marked as "needing reply":

I have not profiled netgraph to have a limitation of 65530 eiface devices
off a single if_bridge, but are allowed multiple bridges with that many
devices.

The problems that you run into with that many devices is that if all the
interfaces are visible to a single jail or single host... your "ifconfig"
command could take several hours (about 4) to enumerate each iface
to the screen.

I didn't mess much with epair because it failed to produce a situation
where I could speak separate subnets over the same wire. Netgraph
made it easy by way of being able to enable promiscuous and disable
the "autosrc" feature (as you perhaps already found in my code you
linked to above).
-- 
Cheers,
Devin



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