Date: Mon, 2 Apr 2018 17:58:13 +0300 From: Daniel Braniss <danny@cs.huji.ac.il> To: "Rodney W. Grimes" <freebsd-rwg@pdx.rh.CN85.dnsmgr.net> Cc: Harry Schmalzbauer <freebsd@omnilan.de>, freebsd-virtualization@freebsd.org Subject: Re: bhyve and arp problem Message-ID: <BCDB257E-3CA3-48FB-8340-05DE52638904@cs.huji.ac.il> In-Reply-To: <201804021351.w32DptK9082637@pdx.rh.CN85.dnsmgr.net> References: <201804021351.w32DptK9082637@pdx.rh.CN85.dnsmgr.net>
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> On 2 Apr 2018, at 16:51, Rodney W. Grimes = <freebsd-rwg@pdx.rh.CN85.dnsmgr.net> wrote: >=20 >>> On 2 Apr 2018, at 15:33, Harry Schmalzbauer <freebsd@omnilan.de> = wrote: >>>=20 >>> 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 >>>>=20 >>>> i know this looks harmless, but it?s annoying >>>=20 >>> You can calm it with >>> 'sysctl net.link.ether.inet.log_arp_movements=3D0' >>>=20 >>> There's also "net.link.ether.inet.log_arp_wrong_iface" and >>> "net.inet.ip.check_interface" which influence related behaviour. >>>=20 >>> 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: >>>>=20 >>>> 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] >>>=20 >>=20 >> 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?) >>=20 >>> 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). >>=20 >>> The recent post indicates non-different MAC-addresses. >>>=20 >>> 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. >>>=20 >>> So I strongly suggest to analyze your setup before altering the >>> mentioned sysctl!!! >>>=20 >> 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 :-( >=20 > Are you trying to use the HOSTS ip address in the GUEST? the client is using the server=E2=80=99s /usr/local, which is mounted = via nfs. so I guess the answer is yes. > 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 this being done with PCI passthrough? again, no. cheers, danny >=20 >=20 > --=20 > Rod Grimes = rgrimes@freebsd.org
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