REDUCTION OF CHURN IN A NETWORK CONTROL SYSTEM

摘要

Some embodiments provide a network control system with techniques for handling failover of network controllers with minimal churn in the network state distributed to the forwarding elements of the network. Specifically, in some embodiments, the local controller designates a waiting period before computing output network state data entries based on the new version of the input network state data entries. Alternatively, or conjunctively, the local controller of some embodiments calculates the changes between the new version of input state data entries and its stored existing version of the input state data entries, and only generates new output network state data entries based on the calculated changes, in order to minimize unnecessary recalculations of the output network state data entries. The new output network state data entries may then be used by the local controller to provision its managed forwarding element.

主权项

1. For a first network controller, a method for maintaining a consistent network state for a set of managed forwarding elements, the method comprising:
determining that a second network controller has disconnected, wherein a first network state at the first network controller is based on a first input state received from the second network controller; receiving a second input state from a third network controller that takes over provision of input state upon the disconnect of the second network controller, the second input state for generating a second network state; maintaining the first network state for a predetermined amount of time after receiving the second input state in order to incorporate a set of updates to the second input state received from the third network controller; and after the predetermined amount of time, generating the second network state based on the second input state and any updates received during the predetermined amount of time.