NIC bonding - multiple VLANs - two NICs

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Good morning RHEL gurus:

Is it possible to configure NIC Bonding on two separate VLANs (VLAN Tagging) using only two NICs?

i.e. Either by using NIC aliases or setting multiple MASTER values in the ifcfg file (or some other method)?

I have a physical server with two NICs that is needed to be on two VLANs - currently the NIC bonding is restricted to one NIC - perhaps out of necessity.

Thoughts?

Thanks
Bill

WB
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Responses

Jamie Bainbridge's picture Red Hat Guru 7252 points
10 May 2016 10:50 PM

I don't quite understand your setup. Can you describe the interface names, and which interfaces have which VLAN tag(s) trunked to them?

For example: "eth1 has untagged traffic and VLAN123, eth2 has untagged traffic and VLAN123, eth3 has VLAN456, eth4 has VLAN456".

If you're asking if a bond can have vlan-tagged interfaces as slaves (eg: bond123 with slaves eth0.123 and eth1.123), yes.

If you're asking if a bond can have two trunk-attached slaves (eg: eth0 and eth1) and then VLAN interfaces configured on top (eg: bond0 with tagged interface bond0.123), yes.

WB Newbie 10 points
11 May 2016 3:44 AM

I have one physical server with only two NICs. I want NIC bonding. I want to connect to two different networks, each using bonding and VLAN tagging.

Ex: ifcfg-bond0.444 AND ifcfg-bond1.555 Each VLAN would use the bonding.

That implies that my ifcfg-eth0 and ifcfg-eth1 NIC config files would need contain something like: MASTER=bond0,bond1

So the question is whether or not an interface config file can host multiple masters.

It would seem that since the bonds are for two different VLANs, and frames that pass through the interface will get tagged with the VLAN ID, there shouldn't be any transmission conflict or collisions. But that's where I could be wrong. That's the question.

Jamie Bainbridge's picture Red Hat Guru 7252 points
11 May 2016 4:04 AM

No, you cannot enslave one physical interface to two masters.

Assuming eth0 and eth1 both have VLAN444 and VLAN555 trunked to them, setup eth0 and eth1 as slaves of bond0, then create bond0.444 with the VLAN444 IP address and subnet, and bond0.555 with the VLAN555 IP address and subnet.

If your slaves don't have both VLANs trunked to them (i.e. eth0 only has VLAN444 and eth1 only has VLAN555), then there is no high availability to be had from these interfaces.

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