Validate wsrep_sync_wait database option

config.example.yml

@@ -52,6 +52,7 @@ database:
 
     # Enforce Galera cluster nodes to perform strict cluster-wide causality checks before executing
     # specific SQL queries determined by the number you provided.
+    # Note: You can only set this option to a number "0 - 15".
     # Defaults to 7.
     # See https://icinga.com/docs/icinga-db/latest/doc/03-Configuration/#galera-cluster
 #    wsrep_sync_wait: 7

pkg/icingadb/db.go

@@ -75,6 +75,9 @@ func (o *Options) Validate() error {
 	if o.MaxRowsPerTransaction < 1 {
 		return errors.New("max_rows_per_transaction must be at least 1")
 	}
+	if o.WsrepSyncWait < 0 || o.WsrepSyncWait > 15 {
+		return errors.New("wsrep_sync_wait can only be set to a number between 0 and 15")
+	}
 
 	return nil
 }