System Upgrade Under High Availability Constraints

摘要

An embedded step is executed to upgrade multiple layers of a system. The embedded step includes multiple nested steps, and each nested step includes a sequence of actions for upgrading one of the layers. A finite state machine defines the state transitions for each nested step. During the execution of the nested steps, an outer step of the nested steps is transitioned from an executing state into a waiting state after the outer step completes a tear-down. During the transitioning of the outer step, the outer step sends a trigger to an inner step of the nested steps to cause the inner step to transition into the executing state. When the inner step is completed, the outer step is transitioned out of the waiting state to execute a build-up phase. Execution of the embedded step is completed when an outermost step of the nested steps is completed.

主权项

1. A method performed by a computer system for executing an embedded step to upgrade a plurality of layers in a software subsystem, the embedded step including a plurality of nested steps, each of the nested steps including a sequence of actions for upgrading one of the layers, the method comprising the steps of:
executing, by the computer system for each of the nested steps, state transitions according to a finite state machine (FSM), wherein the step of executing further comprises:
transitioning an outer step of the nested steps from an executing state into a waiting state of the FSM after the outer step completes a tear-down phase of the sequence of actions, wherein, during the transitioning of the outer step, the outer step sends a trigger to an inner step of the nested steps to cause the inner step to transition into the executing state; andtransitioning the outer step out of the waiting state to execute a build-up phase of the sequence of actions when the inner step is completed; and completing the execution of the embedded step when an outermost step of the nested steps is completed.