Patent attributes
Techniques are disclosed describing an In-Service Software Upgrade for a Software Defined Networking (SDN) controller of a cloud data center. A cloud data center includes a first SDN controller configured to perform session management of a plurality of session instances, an orchestration engine communicatively coupled to the first SDN controller via a northbound application program interface (API); and a plurality of compute nodes configured to perform compute functions for the plurality of session instances. In response to receiving a request to perform an in-service software upgrade (ISSU) of the first SDN controller, the orchestration engine spawns a second, upgraded SDN controller on the cloud data center. An ISSU process initializes the second SDN controller and transfers session management for the plurality of session instances from the first SDN controller to the second SDN controller. Finally, the ISSU process removes the first SDN controller from the cloud data center.