Multiple external networks on a single vswitch

[zenking]

I'm trying to figure out (among other things) if I need more than one vmkernel on the same vswitch. It's related to a question I posted last week, but I've figured out a few things since. Here is the setup (somewhat minimized for the sake of this discussion) -

2 vSphere 5.5 hosts, each with:

1 vmnic connected to trunk capable external switch ports (vSwitch0); this is currently the management network

1 vmnic connected to private switch for vmotion (vSwitch1)

1 vmnic connected via private switch to iscsi array; the private switch has separate vlan for iscsi (vSwitch2)

Vmotion and iscsi work great, so I'm mainly concerned with the external networking. Currently, all VMs are on untagged vlans. We will be changing to 2 tagged vlans on different subnets - 10.1.10.x and 10.2.20.x. The VMs will need to talk to each other while on different hosts. So, does that mean I need 2 vmkernels on vSwitch0 - one for the 10.1 subnet and another for the 10.2 subnet? Then at least one port group per vmkernel and matched vlan IDs for port group and vmkernel?

OR

Do I really only need a single vmkernel on vSwitch0 with 2 different port groups for the different vlans? IE, will VMs with different networks than the mgmt network be able to communicate through the external switch to VMs on the other host?

Also, I expect that the external ports will need to be set to allow untagged 1, tagged 10 and tagged 20 - is that right?

[rcporto · Accepted solution]

So, does that mean I need 2 vmkernels on vSwitch0 - one for the 10.1 subnet and another for the 10.2 subnet? Then at least one port group per vmkernel and matched vlan IDs for port group and vmkernel?

No... you don't need multiple VMkernel to be able to use different virtual machine networks in your ESXi host.

Do I really only need a single vmkernel on vSwitch0 with 2 different port groups for the different vlans? IE, will VMs with different networks than the mgmt network be able to communicate through the external switch to VMs on the other host?

Yes, just use the existent VMkernel management interface and create two port groups, one for each VLAN. Yes, VMs from VLAN different from management network will be able to communicate, BUT your physical switch need to be configured to allow traffic from multiple VLANs.

Also, I expect that the external ports will need to be set to allow untagged 1, tagged 10 and tagged 20 - is that right?

This should work.

[zenking]

Thanks, Richardson. I had a "Well, DUH!" moment last night after I posted where I realized that since a vswitch is just the virtual version of a physical switch and a physical switch doesn't need its own ip for each subnet that passes through it, I didn't need the additional vmkernel. I appreciate the response and the confirmation.