Elasticsearch logfile audit output

The logfile audit output is the only output for auditing. By default, it writes data to the <clustername>_audit.json file in the logs directory. The file is also rotated and archived daily or upon reaching the 1GB file size limit.

In self-managed clusters, you can configure how the logfile is written in the log4j2.properties file located in ES_PATH_CONF (or check out the relevant portion of the log4j2.properties in the sources). However, Elastic strongly recommends using the default Log4j2 configuration.

Orchestrated deployments (ECH, ECE, and ECK) do not support changes in log4j2.properties files of the Elasticsearch instances.

For Elasticsearch configuration options that control event filtering in audit logs, refer to Configure audit logging.

The audit events are formatted as JSON documents, and each event is printed on a separate line in the <clustername>_audit.json file. The entries themselves do not contain the end-of-line delimiter. The audit event JSON format is somewhat particular, as most fields follow a dotted name syntax, are ordered, and contain non-null string values. This format creates a structured columnar aspect, similar to a CSV, that can be more easily inspected visually (compared to an equivalent nested JSON document).

There are however a few attributes that are exceptions to the above format. The put, delete, change, create and invalidate attributes, which are only present for events with the event.type: "security_config_change" attribute, contain the nested JSON representation of the security change taking effect. The contents of the security config change are hence not displayed as top-level dot-named fields in the audit event document. That’s because the fields are specific to the particular kind of security change and do not show up in any other audit events. The benefits of a columnar format are therefore much more limited; the space-saving benefits of the nested structure is the favoured trade-off in this case.

When the request.body attribute is present (refer to Auditing HTTP request bodies), it contains the full HTTP request body as an escaped JSON string.

Refer to audit event types for a complete list of fields, as well as examples, for each entry type.