Upgrade an online cluster
This guide provides step-by-step instructions for performing an in-place, online rolling upgrade of a multi-node Cassandra cluster. An online upgrade allows the cluster to continue serving data while each node in the cluster is upgraded. To complete the upgrade, you must separately upgrade each node in the cluster to the desired version of Cassandra.
During the process of upgrading an individual node, the node is taken offline. While the node is offline, requests continue to be served by the other online nodes that hold the replicas of the offline node’s data. Once you’ve successfully upgraded and restarted a node, it will be added back into the cluster. You’ll then repeat this process with each successive node in the cluster until all nodes have been upgraded.
The upgrade procedures are grouped into phases between which the work can generally be paused. In each phase there are several steps which, where practicable, should be completed without stopping.
Before you upgrade
Before attempting to upgrade Cassandra in production, it’s vitally important to create an upgrade plan that’s tailored to your specific environment. If you have yet to create an upgrade plan, see Planning your upgrade.