Surge upgrades create duplicate, up to a maximum of 10, nodes during cluster upgrade.
After the upgraded nodes are created, workloads are drained from the old nodes to the new nodes, before the old nodes are deleted. Surge upgrade thus reduces disruptions to workloads during cluster upgrades.
Surge upgrades reduce the overall cluster upgrade time and impact on applications. We recommend enabling surge upgrades when upgrading an existing cluster. Creating a new cluster automatically enables surge upgrades by default.
Surge upgrades are available at no additional cost, meaning there is no additional cost for the duplicate nodes created during surge upgrades.