Date: Mon, 2 Apr 2018 09:07:56 -0700 (PDT) From: "Rodney W. Grimes" <freebsd-rwg@pdx.rh.CN85.dnsmgr.net> To: Daniel Braniss <danny@cs.huji.ac.il> Cc: Harry Schmalzbauer <freebsd@omnilan.de>, freebsd-virtualization@freebsd.org Subject: Re: bhyve and arp problem Message-ID: <201804021607.w32G7uFa083223@pdx.rh.CN85.dnsmgr.net> In-Reply-To: <BCDB257E-3CA3-48FB-8340-05DE52638904@cs.huji.ac.il>
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> > On 2 Apr 2018, at 16:51, Rodney W. Grimes <freebsd-rwg@pdx.rh.CN85.dnsmgr.net> wrote: > > > >>> On 2 Apr 2018, at 15:33, Harry Schmalzbauer <freebsd@omnilan.de> wrote: > >>> > >>> Bez?glich Daniel Braniss's Nachricht vom 30.03.2018 13:16 (localtime): > >>>> hi, > >>>> this is my first attempt at bhyve, and so far all seems ok, except > >>>> in my guest, the mac address of the hosting keeps flipping, ie, every 20 minutes > >>>> i see a message : > >>>> ? arp: nnn (the hosting ip) moved from xxxx to yyyy > >>>> on both the host and guest I?m running a very resent -stable. > >>>> the yyyy is the mac of the host nic, while the xxxx is the tap0 > >>>> > >>>> i know this looks harmless, but it?s annoying > >>> > >>> You can calm it with > >>> 'sysctl net.link.ether.inet.log_arp_movements=0' > >>> > >>> There's also "net.link.ether.inet.log_arp_wrong_iface" and > >>> "net.inet.ip.check_interface" which influence related behaviour. > >>> > >>> You also posted (documentationized IP-addresses): > >>>> I think the problem starts with the host seeing the client/guest on 2 interfaces, the nic (mlnxen0) and the tap(tap0) > >>>> on the host: > >>>> > >>>> arp -a > >>>> ... > >>>> bhv-00.cs.huji.ac.il (192.0.2.246) at xx.xx.xx.xx.xx on tap0 expires in 1001 seconds [ethernet] > >>>> bhv-00.cs.huji.ac.il (192.0.2.246) at xx.xx.xx.xx.xx on mlxen0 expires in 644 seconds [ethernet] > >>> > >> > >> the above 2 lines are on the host running bhyve (server?) and the MACs belong to the client, and they are identical, > >> there is no complaints. > >> (BTW, did you change the ip?s?) > >> > >>> Initially, you reference two MAC-addresses with xxxx and yyyy. > >> this is on the client, where the MAC are different (it?s of the hosting computer). > >> > >>> The recent post indicates non-different MAC-addresses. > >>> > >>> If xxxx and yyyy - resp. xx.xx.xx.xx.xx - are equal (but seen on > >>> different interfaces), this wouldn't get logged I think. > >>> But it was the only harmless case for straight forward setups. > >>> Even with STP/LACP/CARP/etc. in place, "arp: IP-address moved" always > >>> indicates a misconfiguration and I don't know any example where the two > >>> different MAC-Addresses for one IP-address were harmless. > >>> While using a single (locally administrated?) MAC address more than once > >>> sitewide _can_ make sense, having two interfaces on one host which both > >>> are on the same ethernet segment like the two interfaces with the same > >>> MAC address, looks like an unintended setup. > >>> > >>> So I strongly suggest to analyze your setup before altering the > >>> mentioned sysctl!!! > >>> > >> I do want to know if there are ip/mac issues, it usually happens when more than one host has the same ip, > >> which is not the case here :-( > > > > Are you trying to use the HOSTS ip address in the GUEST? > > the client is using the server?s /usr/local, which is mounted via nfs. > so I guess the answer is yes. I didnt mean to access it, I meant did you assign the same IP to the GUEST that is assigned on the HOST. I suspect the answer here is no from other context. > > And how do you have an mlxen interface in a GUEST? > no > the guest has only vtnet0 and lo0 > the ip of the client is obtained via dhcp > on the server, there is a bridge, bridge0 and it bridges between the taps and the mxlen0 Is 192.0.2.246 on the mlxen0 interface, or on the bridge0? I believe you need to move the ip from the interface to the bridge to have this work right. > > > Is this being done with PCI passthrough? > again, no. > > cheers, > danny -- Rod Grimes rgrimes@freebsd.org
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