Switching data sources during rolling upgrade of a leader-based distributed service with minimal disruptions

A system comprising:

• a plurality of computing devices of a cluster, each of the plurality of computing devices comprising a processor and a memory communicatively coupled to the processor, the memory storing computer-readable instructions that, when executed by the processor, cause the processor to:
• determine that an upgrade is complete on all of the plurality of computing devices of the cluster;
• in response to determining the upgrade is complete, restart all of the plurality of computing devices;
• and
• upon restarting of all of the plurality of computing devices:
• one of the plurality of computing devices is designated as a leader device;
• switch each of the plurality of computing devices from a first data source to a second data source upon restarting;
• the leader device migrates a task in the first data source to the second data source;
• and
• a non-leader device of the plurality of computing devices executes the task from the second data source instead of the first data source upon determining migration of the task to the second data source is complete.

A non-transitory computer-readable media comprising computer-executable instructions embodied thereon that, when executed by a processor of each of a computing device of a plurality of computing devices of a cluster cause the respective processor to:

• determine that an upgrade is complete on all of the plurality of computing devices of the cluster;
• in response to the determining, restart all of the plurality of computing devices;
• and
• upon restarting of all of the plurality of computing devices:
• one of the plurality of computing devices is designated as a leader device;
• switch each of the plurality of computing devices from a first data source to a second data source,
• the leader device migrates a task in the first data source to the second data source;
• and
• a non-leader device of the plurality of computing devices executes the task from the second data source instead of the first data source upon determining migration of the task to the second data source is complete.