Date: Mon, 26 Feb 2018 13:13:18 +0100 From: Harry Schmalzbauer <freebsd@omnilan.de> To: Ruben <mail@osfux.nl> Cc: FreeBSD virtualization <freebsd-virtualization@freebsd.org> Subject: Re: superfluous host interfaces Message-ID: <5A93F9DE.9090908@omnilan.de> In-Reply-To: <54f9019e-6e86-8e10-32d7-9f14d159bb0a@osfux.nl> References: <20180225131401.GA3138@v007.zyxst.net> <5A93CEB6.1080406@omnilan.de> <a0ccbf77-ec23-127c-0529-ddb05dc689e3@osfux.nl> <5A93D9D0.4090804@omnilan.de> <54f9019e-6e86-8e10-32d7-9f14d159bb0a@osfux.nl>
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Bezüglich Ruben's Nachricht vom 26.02.2018 11:34 (localtime): > On 26/02/2018 10:56, Harry Schmalzbauer wrote: … >> Another, personally very significant, reason is that you'll get a >> superfluous host interface for each if_bridge(4), which makes the output >> of plain ifconfig(8) kind of unreadable. … > > By superflous host interfaces, do you mean the tap interfaces configured > for each vm together with the bridge interfaces they are "bundled" in? Additionally to the if_tap(4) ethernet host interfaces, you also get if_bridge(4) ethernet interfaces, named bridgeX if I remember correctly. The if_bridge(4) host interface is for control purposes only on a VM-SDN host – at least with my setups. I never needed to make use of IP numbered bridges. And I don't need to utilize any if_bridge(4) features like STP, so I consider the bridgeX host interfaces as superfluous in the VM-SDN use case. I'd call the if_tap(4) host interfaces likewise superfluous – you would only need the corresponding character devices – but that's been implemented long before the need for SDN setups, so it is like it is. And using ng_bridge(4) instead of if_bridge(4) doesn't change the need for if_tap(4). Only with vale(4) switches, bhyve(8) was able to provide virtio-net connection wihtout "spamming" the host's ethernet interface list (no tapX, no bridgeX). > Overall I'm very happy with my bhyve setups atm. If there are any > speed-/administrative-advantages that come with bridge_ng however, I'm > very interested in switching to such a setup (or at least play with it). > I'm running my vm's without any helper project so I'm flexible enough to > do some fiddling :P > > Do you know of any documentation on using bridge_ng together with bhyve? > My search-engines don't turn up much Im affraid and I haven't stumbled > on it before. Unfortunately it's not too easy to get started with netgraph. Besides numerous man pages for the different nodes (ng_bridge(4) e.g.), I only know the following source for a good overview: http://www.netbsd.org/gallery/presentations/ast/2012_AsiaBSDCon/Tutorial_NETGRAPH.pdf One convenience disadvantage with ng_bridge(4) is that you have to assign MACs manually, while if_bridge(4) does that itself (adjustable by sysctl net.link.bridge.inherit_mac). And you need to script all setups yourself. Almost all of my setups seem to be awkward enough that I always had to do some local scripting, so that wasn't really a disadvantage for me. If you're happy with your setup, I don't think you gain anything from switching to ng_bridge(4), besides learning to control netgraph(4) (which is very desirable imho). I haven't had time left to do useful benchmarking regarding ng_bridge(4) vs. if_bridge(4). I even don't know if netgraph nodes are still limited to single threads. But rough load comparings on a IvyBride machine showed similar resource usage for both bridges, both easy capable of 1GbE saturation with small frames (while I remember one run with ng_bridge(4) and if_vmnet(4), which couldn't deliver 1GbE speed, and I wanted to falsify for vmnet/tap difference... just ran out of time :-( ). -harry
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