US Patent 10530815 Seamless service updates for cloud-based security services

The disclosed embodiments disclose techniques for seamlessly updating a cloud-based security service. A dispatcher virtual machine (VM) executing in a cloud data center receives network requests sent from clients located in a remote enterprise location to untrusted remote sites, and routes this network traffic through a chain of security service VMs that analyze the network traffic. During operation, the dispatcher VM determines that an existing security service VM in the chain needs to be upgraded to an updated version, and instantiates an updated chain of security service VMs that includes this updated version. The dispatcher VM then seamlessly transfers the flow of network traffic from the initial chain to the updated chain to seamlessly update the cloud-based security service without interruption. Upon determining that the updated version is operating correctly, the dispatcher VM halts and deallocates the previous version and any other unneeded portions of the initial chain.