Abstract: A method for maintaining fault tolerance in a storage cluster is provided. Embodiments include receiving, by a management component associated with a distributed data store on a cluster of host machines, a request to place a first host machine of the cluster of host machines in a maintenance mode, wherein the first host machine stores given data of the distributed data store. Embodiments include determining whether a second host machine that does not currently store any data of the distributed data store exists in the cluster of host machines. Embodiments include determining, based on whether the second host machine exists in the cluster of host machines, whether to transfer the given data of the distributed data store from the first host machine to the second host machine. Embodiments include initiating the maintenance mode on the first host machine.

Abstract: The present disclosure relates to health measurement and remediation of distributed systems upgrades. One method includes communicating a request for a health status to a cluster store provided by a cluster of hosts of a software-defined datacenter, wherein the cluster store includes a plurality of process instances undergoing a rolling upgrade, receiving a health status indication in response to the request, the health status indication determined based on a determination of whether the cluster store is available and a determination of whether the cluster store is operational, and taking a remediation action in response to the health status indication exceeding a threshold.

Abstract: The present disclosure relates to using maintenance mode to upgrade a distributed system. One method includes determining that a first host of a cluster of a software-defined datacenter (SDDC) is to be upgraded as a part of a rolling upgrade of the hosts of the cluster, wherein the first host is executing a process instance of a cluster store, demoting the process instance to a proxy, creating a replica of the process instance using a different proxy on a second host of the cluster, instructing the first host to enter a maintenance mode, upgrading the first host, and instructing the first host to leave the maintenance mode.

Abstract: The present disclosure relates to using maintenance mode to upgrade a distributed system. One method includes determining that a first host of a cluster of a software-defined datacenter (SDDC) is to be upgraded as a part of a rolling upgrade of the hosts of the cluster, wherein the first host is executing a process instance of a cluster store, demoting the process instance to a proxy, creating a replica of the process instance using a different proxy on a second host of the cluster, instructing the first host to enter a maintenance mode, upgrading the first host, and instructing the first host to leave the maintenance mode.