IPAM configuration¶

Starting with the Liberty release, OpenStack Networking includes a pluggable interface for the IP Address Management (IPAM) function. This interface creates a driver framework for the allocation and de-allocation of subnets and IP addresses, enabling the integration of alternate IPAM implementations or third-party IP Address Management systems.

The basics¶

The IPAM implementation within OpenStack Networking provides two basic flavors (pluggable IPAM, non-pluggable IPAM). By default, the non-pluggable IPAM is enabled. This provides backward compatibility with older releases. In contrast, the pluggable implementation will require a database migration to support upgraded systems. This migration is planned for the Mitaka release.

The reference driver for the pluggable implementation is considered experimental at this time. It does not provide additional functionality beyond the non-pluggable implementation, but does provide a basis for custom or third-party developed drivers. This can enable, for example, development of drivers that use different algorithms to allocate an IP address.

To enable the pluggable implementation, you must specify the driver to use in the neutron.conf file. The internal driver refers to the reference implementation.

ipam_driver = internal

The documentation for any alternate drivers will include the value to use when specifying that driver.

Known limitations¶

The driver interface is designed to allow separate drivers for each subnet pool. However, the current implementation allows only a single IPAM driver system-wide.
Database migrations are not available to convert existing OpenStack installations to the new reference implementation of the pluggable IPAM. This migration is planned for the Mitaka release.
Third-party drivers must provide their own migration mechanisms to convert existing OpenStack installations to their IPAM.