High availability in-service software upgrade using virtual machine instances in dual control units of a network device

摘要

Techniques are described for providing high availability (HA) during an in-service software upgrade (ISSU) of a network device, e.g., a router, by running a pair of virtual machines on each of a primary control unit and a backup control unit within the router. First virtual machines may be run on the primary and backup control units to provide high availability for the router. Upon receiving an ISSU request for the router, second virtual machines may be initialized on the primary and backup control units. If the ISSU of the primary control unit fails such that the first and second virtual machines on the primary control unit are executing different software systems, the virtual machines on the backup control unit may provide high availability for the router. Similarly, the virtual machines on the primary control unit may provide high availability for the router during the ISSU of the backup control unit.

主权项

1. A method comprising:
running a first virtual machine (VM) on a primary control unit of a network device, wherein the first VM executes a first operating system that controls routing functionality of the network device and controls an in-service software upgrade (ISSU) of the network device; running a first backup VM on a backup control unit of the network device, wherein the first backup VM executes the first operating system and provides high availability for the network device during operation of the routing functionality by the first VM; in response to receiving an ISSU request with the first VM on the primary control unit, initializing a second VM on the primary control unit and a second backup VM on the backup control unit, wherein each of the second VM and the second backup VM execute the first operating system; performing the ISSU on the primary control unit by upgrading the second VM to a second operating system, switching control of the routing functionality from the first VM to the second VM, and upgrading the first VM to the second operating system, wherein, when the first VM and the second VM are executing different operating systems, the first and second backup VMs executing the first operating system on the backup control unit provide high availability for the network device during the ISSU of the primary control unit; and if the first VM on the primary control unit fails during the ISSU when the first VM and the second VM are executing different operating systems, switching control of the routing functionality from the first VM on the primary control unit to the first backup VM on the backup control unit, wherein the second backup VM on the backup control unit provides high availability for the network device during operation of the routing functionality by the first backup VM.