When Cluster Has Nodes at Different Software Version Levels

The rolling upgrade feature is designed to enable business continuity while a cluster is being upgraded. The window of time when a cluster has nodes of varying versions--that is, when it is a mixed-version cluster--should be small. During this time, do not make either application code changes or configuration changes.

These configuration changes are not allowed:

• Changes to index, forest, database, application server, host, group, and cluster settings.

• Changes to security settings such adding, changing, or deleting roles, users, privileges, credentials, certificates, and so on.

• Adding, removing, or updating TDE templates.

• Adding, removing, or updating redaction rules.

These actions are not allowed:

• Manual merges.

• Reindexing. Disable reindexing while the cluster has nodes at different software version levels.

These actions are allowed:

• Changing error log settings.
• Adding trace events to debug issues.