General upgrade procedure
The upgrade process for DataStax Enterprise is aimed at providing minimal downtime (ideally zero). With a few exceptions, the cluster will continue to work as though it were on the older version until all of the nodes in the cluster have been upgraded.
To perform an upgrade with zero downtime, we recommend performing the upgrade as a rolling restart. The procedure for the rolling upgrade is:
- Make a backup of the data by taking a snapshot of the node to be upgraded.
- Stop the node.
- Install the new product.
- Configure the new product.
- Start the node.
- Check the logs for warnings, errors and exceptions.
- Repeat these steps for each node in the cluster.
While the cluster is in a partially upgraded state, please observe the general limitations.