XenServer Networking Configuration

Keeping in mind this diagram:

{{http://wiki.openstack.org/XenServer/XenXCPAndXenServer?action=AttachFile&do=get&target=XenServer-dom0-domU.png}}

Key Points

We are assuming the XenServer has three physical interfaces: eth0, eth1, eth2
This means Dom0 has the following bridges: xenbr0, xenbr1, xenbr2
The Dom0 also has the host local xenapi network, usually the XenServer has the address 169.254.0.1

DomU config:

The DomU is a PV virtual machine (has a kernel with the para-virtualization extensions)
It generally has four interfaces

    eth0 -> connected to xenapi (xapi trafic)
    eth1 -> xenbr2 Tenant network traffic
    eth2 -> xenbr0 Management traffic (MySQL, RabbitMQ, Glance, etc)
    eth3 -> xenbr1 Public traffic (floating ip, api endpoints)

Key Flags you may need to change

Each have the DevStack setting and the nova.conf entry

Public Interface

The interface on DomU that connects to the public network. Used by nova-network so it sends the floating ip traffic on the correct network.

PUBLIC_INTERFACE=eth3 public_interface=eth3

Guest Interfaces

The interface on XenServer that has Tenant (also called VM instance or Guest) traffic.

It should be the same interface as the (trunk) bridge your DomU's tenant network is attached to.

GUEST_INTERFACE=eth2

This influences the following two flags:

vlan_interface=eth2 (This is the XenServer interface on which a bridge on the correct VLAN will be created, and then the VM will be attached to that bridge)
flat_interface=eth2 (This is the XenServer interface the bridge on which the instance traffic will sit on)

Flat Network Bridge

Only needed if you are using Flat or FlatDHCP.

This is the XenServer bridge on which the VM instances will have their VIFs attached. This should be the same has the bridge your DomU's Guest Interface is attached to.

FLAT_NETWORK_BRIDGE_DEFAULT=xenbr2
flat_network_bridge=xenbr2

Network HA

This works the same on XenServer as any other hypervisor:

--multi_host flag
nova-network must be run on every compute host

XenServer/NetworkingFlags