[CentOS] C8 - KVM on bridge on VLAN on team issues.

Wed Jun 17 13:59:26 UTC 2020
Deventer-2, M.S.J. van <M.S.J.vanDeventer-2 at umcutrecht.nl>

Hi,

the first thing that comes to mind, did you set ip_forward to enable in
/etc/sysctl.conf ?
net.ipv4.ip_forward = 1

Should explain why you IP on the bridge works but not on the vms.

  Regards,

   Michel

On Wed, 2020-06-17 at 09:43 -0400, Lamar Owen wrote:
> As part of my initial KVM host on C8 deployment, I decided to set up 
> some HA features on the new host, specifically NIC teaming. Teaming 
> seems to be bond++ of a sort, so I thought I would at least try it. 
> So 
> here's the scenario:
> 
> 1.) Server with two gigabit ethernet ports, two Cisco switches.
> 
> 2.) During install, used the 'Server with GUI' group and added the 
> virtualization packages.
> 
> 3.) During install, set up team0 to include the two gig-e ports set
> up 
> active-backup (two switches).
> 
> 4.) During install, set up three bridges, with the slave devices
> being 
> VLANs pointed to the team0 subinterfaces (using VLANs 68, 101, and
> 302; 
> 101 is to be the management bridge for the host, with guests on all 
> three VLANs).  So, for instance, bridge101 has a slave that is
> VLAN101 
> that points to team0.101 with a VLAN ID of 101.  The bridge101
> interface 
> has a manual IP address, but bridge68 and bridge302 do not (IPv4 
> disabled; IPv6 Ignore)
> 
> 5.) After reboot, the bridge101 interface comes up, and I
> successfully 
> connect to the host, since the install is 8.1.1911, I ran a 'dnf
> update' 
> up to 8.2.2004, which went well, then I successfully set up and used 
> cockpit, cockpit-bridge, cockpit-machines, again over the IP address
> on 
> bridge101.
> 
> 
> Ok, now that the base connectivity is working:
> 
> 1.) Connect to the host (traffic on bridge101 over team0.101) using 
> virt-manager on my laptop and install a C8 guest, with the network 
> pointed to bridge302, and a manual IP address.
> 
> 2.) After reboot of guest, there is no IP connectivity to the
> guest's 
> gateway on VLAN302.
> 
> 3.) HOWEVER, the gateway's MAC address shows up in the host's bridge
> fdb 
> for VLAN302, AND in the arp output for the guest; ALSO, the MAC
> address 
> for the guest shows on the cisco switch 'show mac-address-table' 
> output.  The output of 'ip --br link' looks normal for this 
> configuration, but there's a disconnect somewhere.  So, since I see
> that 
> VLAN101 is passing traffic to the bridge correctly (since the
> management 
> IP is on that VLAN), I try to set up a guest on VLAN101; no dice, no 
> work, but the management IP still works fine.
> 
> 
> So, does anyone here have a working setup with KVM guests connecting
> to 
> bridges using 802.1q VLANs on top of a team?  Or even on top of a
> bond 
> (I can reinstall and set it up as a bond easily enough, using 
> active-backup, as far as I know; and, yes, I would reinstall the
> host 
> from scratch to do this).
> 
> _______________________________________________
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> CentOS at centos.org
> https://lists.centos.org/mailman/listinfo/centos
-- 
Michel van Deventer

Integratie Specialist | Divisie Laboratoria, Apotheek en Biomedische
Genetica, Infra Services & Integration

Universitair Medisch Centrum Utrecht | Kamernummer 2.139
Tel. 06-25710398

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