Provider-network-partial-specs

Overview

Currently, all provider attributes for networks are chosen by:

• neutron-server for tenant networks,
• neutron admin for provider networks.

The aim of this functionality is to allow to the neutron admin to provide some provider network attributes and delegate when possible the choice of remaining provider attributes to neutron.

Use Cases

This functionality could be used when :

• creating networks for bare metal instances: neutron admin creates provider-networks with provider:network_type=vlan and delegates to neutron-server the choice of provider:physical_network and provider:segmentation_id using tenant-network pools,
• creating service oriented networks which imposes some provider attributes: neutron creates provider-networks with previous attributes and delegates to neutron-server the choice of remaining provider attributes using tenant-network pools.

Examples

ML2 config context:

[ml2]
tenant_network_types = gre
type_drivers = vlan,gre,flat
 
[ml2_type_flat]
flat_networks = physnet1,physnet2
 
[ml2_type_vlan]
network_vlan_ranges = physnet3:300:319,physnet4:400:419,physnet5
 
[ml2_type_gre]
tunnel_id_ranges =1000:1999

Current features

neutron net-create tenant-net 
# create a tenant network

neutron net-create --provider:network_type=vlan --provider:physical_network=physnet4 --provider:segmentation_id=123 provider-net
# create a vlan provider network on physnet physnet5 for vlan 123

New features

neutron net-create --provider:network_type=vlan vlan-net
# create a vlan provider network (chosen in physnet3:300:319,physnet4:400:419)

neutron net-create --provider:network_type=vlan --provider:physical_network=physnet3 physnet-vlan-net
# create a vlan provider network on physnet physnet3 (segmentation_id chosen in 300:319)

neutron net-create --provider:network_type=vlan --provider:physical_network=physnet5 no-net
# raise an error because no network matchs requirements 
 
neutron net-create --provider:network_type=flat flat-net
# create a flat provider network (chosen in physnet1, physnet2)

API impacts

This functionality will change provider attributes constraints on provider network create:

• provider:network_type is required,
• when provider:network_type=vlan, provider::physical_network and provider:segmentation_id become optional, provider:segmentation_id can be provided only if provider::physical_network is provided (otherwise raise a http bad request),
• when provider:network_type=gre or vxlan, provider:segmentation_id becomes optional,
• when provider:network_type=flat, provider::physical_network becomes optional (not sure for the moment),
• when provider:network_type=local, no impact.

If some provider attributes are not provided, neutron will try to find in tenant network pools a network respecting provided provider attributes, if not network is found a http bad request (http code to discuss) is returned.

Implementation

Options (to discuss):

• Define alternative TypeDriver implementations for vlan/gre/vxlan/flat supporting to provide partial provider network specs.
• Update current TypeDriver implementations supporting to provide partial provider network specs.