Abstract: An upgrade campaign is generated for runtime execution on a highly available system. The highly available system includes virtual machines (VMs) that are enabled for migration between virtual machine monitors (VMMs). VM migration is disabled for the VMs to be added, modified and removed in the upgrade campaign. A first set, a second set and a third set of sub-trees are identified from tree views of the source configuration and the target configuration. Each sub-tree contains entities representing a subset of the VMs and the VMMs. Each sub-tree of the first set includes entities tagged for addition only, each sub-tree of the second set includes entities tagged for modification, and each sub-tree of the third set includes entities tagged for removal only. An upgrade procedure is generated for each sub-tree, with an indication of the order of execution. Then VM migration is reenabled according to the target configuration.

Abstract: 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.