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.
In Liberty and Mitaka, the IPAM implementation within OpenStack Networking provided a pluggable and non-pluggable flavor. As of Newton, the non-pluggable flavor is no longer available. Instead, it is completely replaced with a reference driver implementation of the pluggable framework. All data will be automatically migrated during the upgrade process, unless you have previously configured a pluggable IPAM driver. In that case, no migration is necessary.
To configure a driver other than the reference driver, specify it
neutron.conf file. Do this after the migration is
complete. There is no need to specify any value if you wish to use the
ipam_driver = ipam-driver-name
There is no need to specify any value if you wish to use the reference
driver, though specifying
internal will explicitly choose the reference
driver. The documentation for any alternate drivers will include the value to
use when specifying that driver.
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.
Third-party drivers must provide their own migration mechanisms to convert existing OpenStack installations to their IPAM.