To provide a mechanism for ordering multiple vNICs on a VM, Quantum Manager has a notion of an integer ''priority'' for each network. When a VM has multiple vNICs, the vNICs are added in ascending priority order (i.e., 0 is highest priority). The priority of a network can be specified at network creation. Consider a deployment where all VMs should have two vNICs: the first (e.g., eth0) connected to the shared public network and a second (e.g., eth1) connected to a private tenant network.
To do this, first create the shared network:
nova-manage network create --label=public --fixed_range_v4=8.8.8.0/24 --priority=0
Then, for each with tenant with UUID X, create a private network:
nova-manage network create --label=tenantX-private --fixed_range_v4=10.0.0.0/24 --project_id=X --priority=1
![[Note]](../common/images/admon/note.png) | Note |
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To allow the CIDR address range for different networks to overlap, you must be using Melange for IP Address Management (see: Using Melange IPAM below). |
If a network is created with no ''priority'', the network has priority 0. Networks should be created such that a VM is never associated with multiple networks of the same priority, as the order of vNICs will be undefined.
