[lxc-users] LXC 2.16 - vxlan.<iface> <MAC> migrated from <eth0> to <eth1>

[Stéphane Graber]

Hi,

Ok, so you're doing your own VXLAN youtside of LXD and then connecting
containers directly to it.

The kernel error is very odd for unicast vxlan... there's really no
reason for it to ever use the other interface...

So I'm assuming the 10.250.1.21 IP is on eth0 and 172.18.22.21 on eth1
(or the reverse)? that is, you don't have both subnets on eth1.

On Tue, Sep 26, 2017 at 09:52:37AM -0400, Ron Kelley wrote:
> Thanks Stephane.
> 
> Here is a “lxc network list” on the hosts:
> 
> rkelley at LXD-QA-Server-04:~$ lxc network list
> +--------+----------+---------+-------------+---------+
> |  NAME  |   TYPE   | MANAGED | DESCRIPTION | USED BY |
> +--------+----------+---------+-------------+---------+
> | eth0   | physical | NO      |             | 0       |
> +--------+----------+---------+-------------+---------+
> | eth1   | physical | NO      |             | 2       |
> +--------+----------+---------+-------------+---------+
> | virbr0 | bridge   | NO      |             | 0       |
> +--------+----------+---------+-------------+————+
> 
> 
> Also, we are using vxlan in unicast mode via eth1.  Each LXD server has a unicast IP address on eth1 that lives in a separate VLAN from eth0 on the directly connected network switch.  If both eth0 and eth1 were in the same VLAN, I could possible an issue.  Once a container is spun it, it is attached to a VXLAN interface off eth1 (i.e.: vxlan.1115)
> 
> Thus, I am scratching my head..
> 
> -Ron
> 
> 
> > On Sep 26, 2017, at 9:02 AM, Stéphane Graber <stgraber at ubuntu.com> wrote:
> > 
> > On Sun, Sep 24, 2017 at 03:27:27PM -0400, Ron Kelley wrote:
> >> Greetings all,
> >> 
> >> Trying to isolate a condition whereby a container providing firewall services seems to stop processing traffic for a short time.  We keep getting the below information in /var/log/syslog of the server running the firewall.  The IP addresses shown match the network interfaces of the remote LXD server running the web server.  These IPs are for the server itself, and not the container IP
> >> 
> >> Sep 24 15:10:25 LXD-Server-04 kernel: [144272.412154] vxlan.1104: 00:11:22:aa:66:a3 migrated from 10.250.1.21  to 172.18.22.21
> >> Sep 24 15:10:26 LXD-Server-04 kernel: [144272.412154] vxlan.1104: 00:11:22:aa:66:a3 migrated from 172.18.22.21 to 10.250.1.21 
> >> Sep 24 15:10:27 LXD-Server-04 kernel: [144272.412154] vxlan.1104: 00:11:22:aa:66:a3 migrated from 10.250.1.21  to 172.18.22.21
> >> Sep 24 15:10:28 LXD-Server-04 kernel: [144272.412154] vxlan.1104: 00:11:22:aa:66:a3 migrated from 172.18.22.21 to 10.250.1.21 
> >> Sep 24 15:10:29 LXD-Server-04 kernel: [144272.412154] vxlan.1104: 00:11:22:aa:66:a3 migrated from 10.250.1.21  to 172.18.22.21
> >> Sep 24 15:10:30 LXD-Server-04 kernel: [144272.412154] vxlan.1104: 00:11:22:aa:66:a3 migrated from 172.18.22.21 to 10.250.1.21 
> >> Sep 24 15:10:31 LXD-Server-04 kernel: [144272.412154] vxlan.1104: 00:11:22:aa:66:a3 migrated from 10.250.1.21  to 172.18.22.21
> >> Sep 24 15:10:32 LXD-Server-04 kernel: [144272.412154] vxlan.1104: 00:11:22:aa:66:a3 migrated from 172.18.22.21 to 10.250.1.21 
> >> 
> >> Notice how they migrate from one interface to another and then back again.  Any idea as to why these messages are getting logged?
> >> 
> >> Thanks.
> >> 
> >> -Ron
> > 
> > Hmm, so I think I'm going to need a bit more details on the setup.
> > Can you show the "lxc network show" for the network on both hosts?
> > 
> > My current guess is that you're using vxlan in multicast mode and both
> > your hosts have two IPs on two subnets. Multicast VXLAN works on both
> > those subnets and it can therefore see the same remote MAC on both,
> > having it flip/flop between the two paths.
> > 
> > -- 
> > Stéphane Graber
> > Ubuntu developer
> > http://www.ubuntu.com
> > _______________________________________________
> > lxc-users mailing list
> > lxc-users at lists.linuxcontainers.org
> > http://lists.linuxcontainers.org/listinfo/lxc-users
> 
> _______________________________________________
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-- 
Stéphane Graber
Ubuntu developer
http://www.ubuntu.com
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