Changed default Docker driver in Release Notes per BZ

Author: mburke5678

release_notes/ocp_3_7_release_notes.adoc

@@ -1029,6 +1029,23 @@ openshift_checks_output_dir=/tmp/checks
 [[ocp-37-metrics-and-logging]]
 === Metrics and Logging
 
+[[ocp-37-journald-system-logs]]
+==== Journald for System Logs and JSON File for Container Logs
+
+Docker log driver is set to `journald` as the default for all nodes. Docker
+`log-driver` can be set to `json-file`. Note that there is no log rate-throttling with
+the `journald` driver. So, there is always a risk for denial-of-service attacks
+from rogue containers.
+
+Fluentd will automatically determine which log driver (`journald` or
+`json-file`) the container runtime is using. Fluentd will now always read logs
+from journald and also *_/var/log/containers_* (if `log-driver` is set to
+`json-file`). Fluentd will no longer read from *_/var/log/messages_*.
+
+See
+xref:../install_config/aggregate_logging.adoc#install-config-aggregate-logging[Aggregating
+Container Logs] for more information.
+
 [[ocp-37-docker-events-and-api-calls-aggregated-to-efk-as-logs]]
 ==== Docker Events and API Calls Aggregated to EFK as Logs