Upgrading multi-instance software using enforced computing zone order

A non-transitory computer-readable medium having program instructions stored thereon that are capable of being executed by a cloud computer system to perform operations comprising:

• receiving an upgrade request to upgrade a plurality of instances, a given one of which is implemented across a plurality of computing zones;
• and
• in response to the upgrade request, initiating respective upgrade processes for the plurality of instances, wherein the respective upgrade processes include a node acquisition portion having a common constraint on parallelization in which nodes for a given one of the plurality of instances are to be acquired in different computing zones according to a specified order, and wherein a given one of the respective upgrade processes further includes:
• after acquiring the nodes in the different computing zones according to the specified order, deploying an updated instance to the acquired nodes to update the given instance.

A non-transitory computer-readable medium having program instructions stored thereon that are capable of being executed by a computer system to perform operations comprising:

• receiving a request to upgrade a plurality of instances of a service that is distributed across a plurality of availability zones that includes a first availability zone and a second availability zone within a particular cloud region;
• causing the plurality of instances of the service to be upgraded according to an availability zone order specifying that a node in the first availability zone is to be secured before a node in the second availability zone, wherein upgrading a first instance of the plurality of instances includes:
• deploying a first node-securing pod to secure a first node for the first availability zone;
• upon the first node being secured by the first node-securing pod for the first availability zone, deploying a second node-securing pod to secure a second node for the second availability zone;
• and
• after the first and second node-securing pods have secured the first and second nodes, deploying an updated instance to the first and second nodes to upgrade the first instance.