A talk I gave with John Belamaric and John Voss from Infoblox

1. 1 | © 2013 Infoblox Inc. All Rights Reserved.1
Subnet Pools and Pluggable IPAM
Liberty Design Summit
May 20th 2015
Carl Baldwin, Neutron Development, HP
John Belamaric, Senior Architect, Infoblox
John Voss, Senior Product Manager, Infoblox

2. 2 | © 2013 Infoblox Inc. All Rights Reserved.2
• No VM connectivity without a valid IP assigned
• Duplicate subnets/IPs in shared or routable space are disastrous
̶ Especially relevant when using provider networks
• Allocation of subnets for large scale deployments can be difficult and
time consuming
̶ Especially for Tenants using non-overlapping addresses
̶ Errors in address planning and quota allocation are difficult to reverse
• Users have multiple/heterogeneous environments
̶ Track IPs/subnets across multiple clusters
̶ Reclaim IPs/subnets that are no longer in use
Why is IPAM important for Neutron?

3. 3 | © 2013 Infoblox Inc. All Rights Reserved.3
• Dynamic Subnet Allocation
̶ Enables definition of per-tenant and shared pools of subnets
̶ Delivered in Kilo
• Pluggable IPAM
̶ Enables integration of home grown or 3rd party IPAM systems
̶ Enables centralized management of addressing across the cloud and
organization
̶ On track for delivery in Liberty
IPAM Enhancements for Neutron

4. 4 | © 2013 Infoblox Inc. All Rights Reserved.4
• What was introduced in Kilo?
̶ Subnet Pool - Range of addresses from which subnets may be allocated
- May be exclusive to a tenant or shared
- Enforces a quota for shared pools
- Simplifies centralized management of subnet allocations to tenants
- Example: 10.0.0.0/16 from which smaller subnets (/20, /23, /24, etc.) are allocated
• How does it work?
̶ Pools can be managed via the API or neutron client
̶ Optionally specify a pool when allocating a subnet
- Leave out the CIDR and just pass a prefix length (or use the default prefix length)
- Specify a CIDR if you want, as long as it fits in the pool without overlap
Subnet Allocation

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Creating a Subnet Pool

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Allocate a Subnet From a Pool

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Allocate a Specific Subnet

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Update the Pool

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First-fit when multiple prefixes

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• Kilo and earlier IPAM is embedded in Neutron
• In Liberty, IPAM services will have a driver-based architecture
̶ Allocation of subnets, fixed and floating IPs handled via IPAM driver
̶ Optionally enabled - by default “built-in” IPAM will be used
̶ Reference driver has no user-facing differences
• Enables alternate drivers
̶ Local drivers with alternate allocation strategies
̶ Third-party drivers to interface with external IPAM
̶ Custom-built drivers to interface with home grown IPAM systems
Pluggable IPAM

11. 11 | © 2013 Infoblox Inc. All Rights Reserved.11
Pluggable IPAM
Neutron Server
Plugin
API
DB Plugin IPAM Driver
Neutron
DB
External IPAM
DHCP Agent
MQ
L3 Agent
L2 Agent
Metadata Agent

12. 12 | © 2013 Infoblox Inc. All Rights Reserved.12
• Address scopes become first-class objects
̶ Created and managed via the API
̶ Routers will not route between them without NAT or (maybe) an override
̶ Associate an RD and RT for BGP advertising (and/or VPN ID)
• Per subnet-pool IPAM driver configurations
̶ Enables different drivers for different pools
̶ Track private spaces locally and reserve external IPAM for routable space
Future Possibilities