In one example, a method for monitoring the state and health of a centralized software defined networking controller includes detecting, by a standby software defined networking controller, when a number of path computation client sessions reported by an active software defined networking controller fails to match an expected number; verifying, by the standby software defined networking controller after expiration of a predefined delay implemented after the detecting, that the number of path computation client sessions reported by the active software defined networking controller still fails to match the expected number; and assuming, by the standby software defined networking controller after the verifying, a role of the active software defined networking controller.