Patent ID: 8849938

Claim:
A method for providing a virtual service in a virtual application distribution chassis, the method comprising: providing a plurality of blades in a virtual application distribution chassis, each of the plurality of blades being coupled to a network switch, wherein a service request by a host for a virtual service is directed by the network switch to a first blade of the plurality of blades, wherein: the first blade is designated as an active blade for the virtual service and a master blade of the plurality of blades in the virtual application distribution chassis, and a second blade is designated as a backup blade for the virtual service and a slave blade of the plurality of blades in the virtual application distribution chassis; detecting, by the second blade, a failure of the first blade as the active blade for the virtual service; in response to detecting the failure of the first blade as the active blade for the virtual service, informing the network switch, by the second blade, to send future service requests for the virtual service to the second blade; detecting, by the second blade, a failure of the first blade as the master blade of the plurality of blades; and in response to detecting the failure of the first blade as the master blade of the plurality of blades, participating, by the second blade, in electing a new master blade from the plurality of blades, the participating in electing comprising, in response to detecting the failure of the first blade as the master blade of the plurality of blades, sending a first master claim message to a third blade of the plurality of blades by the second blade, the first master claim message comprising a blade priority for the second blade; receiving a second master claim message from the third blade by the second blade, the second master claim message comprising a blade priority for the third blade; comparing, by the second blade, the blade priority for the third blade obtained from the second master claim message with the blade priority for the second blade, and in response to determining that the blade priority of the third blade is higher than the blade priority of the second blade, maintaining the slave status of the second blade.