Reject queries from client connections.
Cluster Nodes can accept or reject queries from client connections. When the Node is configured to reject queries, it continues to replicate write-sets from the cluster and clients can still connect to the Node, but if the client attempts to execute a query, the query it returns an error.
This system variable allows you to specify whether and how the node rejects client queries:
Cluster Node accepts client queries.
Cluster Node rejects client queries.
Cluster Node rejects client queries and kills existing client connections, including the current connection, without waiting for any currently running queries to complete.
ENUM (NONE, ALL, ALL_KILL)
Additional information on this topic may be found in the MariaDB Public Knowledge Base.