---
title: Elasticsearch output settings
description: Specify these settings to send data over a secure connection to Elasticsearch. In the Fleet Output settings, make sure that Elasticsearch output type...
url: https://www.elastic.co/docs/reference/fleet/es-output-settings
products:
  - Elastic Agent
  - Fleet
applies_to:
  - Elastic Cloud Serverless: Generally available
  - Elastic Stack: Generally available
---

# Elasticsearch output settings
Specify these settings to send data over a secure connection to Elasticsearch. In the Fleet [Output settings](/docs/reference/fleet/fleet-settings#output-settings), make sure that Elasticsearch output type is selected.

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<definitions>
  <definition term="Hosts">
    The Elasticsearch URLs where Elastic Agents will send data. By default, Elasticsearch is exposed on the following ports:
    <definitions>
      <definition term="9200">
        Default Elasticsearch port for self-managed clusters
      </definition>
      <definition term="443">
        Default Elasticsearch port for Elastic Cloud
      </definition>
    </definitions>
    **Examples:**
    - `https://192.0.2.0:9200`
    - `https://1d7a52f5eb344de18ea04411fe09e564.fleet.eu-west-1.aws.qa.cld.elstc.co:443`
    - `https://[2001:db8::1]:9200`
    Refer to the [Fleet Server](https://www.elastic.co/docs/reference/fleet/fleet-server) documentation for default ports and other configuration details.
  </definition>
  <definition term="Elasticsearch CA trusted fingerprint">
    HEX-encoded SHA-256 of a CA certificate that's present in the certificate chain Elasticsearch sends during the TLS handshake. If this certificate is found in the chain, it'll be added to the `certificate_authorities` list and the handshake will continue normally. For more information, refer to [Using certificate fingerprints](https://www.elastic.co/docs/reference/fleet/certificate-fingerprints).
  </definition>
  <definition term="Proxy">
    Select a proxy URL for Elastic Agent to connect to Elasticsearch. To learn about proxy configuration, refer to [Using a proxy server with Elastic Agent and Fleet](https://www.elastic.co/docs/reference/fleet/fleet-agent-proxy-support).
  </definition>
  <definition term="Advanced YAML configuration">
    YAML settings that will be added to the Elasticsearch output section of each policy that uses this output. Make sure you specify valid YAML. The UI does not currently provide validation.
    See [Advanced YAML configuration](#es-output-settings-yaml-config) for descriptions of the available settings.
  </definition>
  <definition term="Make this output the default for agent integrations">
    When this setting is on, Elastic Agents use this output to send data if no other output is set in the [agent policy](https://www.elastic.co/docs/reference/fleet/agent-policy).
  </definition>
  <definition term="Make this output the default for agent monitoring">
    When this setting is on, Elastic Agents use this output to send [agent monitoring data](https://www.elastic.co/docs/reference/fleet/monitor-elastic-agent) if no other output is set in the [agent policy](https://www.elastic.co/docs/reference/fleet/agent-policy).
  </definition>
  <definition term="Performance tuning">
    Choose one of the menu options to tune your Elastic Agent performance when sending data to an Elasticsearch output. You can optimize for throughput, scale, latency, or you can choose a balanced (the default) set of performance specifications. Refer to [Performance tuning settings](#es-output-settings-performance-tuning-settings) for details about the setting values and their potential impact on performance.
    You can also use the [Advanced YAML configuration](#es-output-settings-yaml-config) field to set custom values. Note that if you adjust any of the performance settings described in the following **Advanced YAML configuration** section, the **Performance tuning** option automatically changes to `Custom` and cannot be changed.
    Performance tuning preset values take precedence over any settings that may be defined separately. If you want to change any setting, you need to use the `Custom` **Performance tuning** option and specify the settings in the **Advanced YAML configuration** field.
    For example, if you would like to use the balanced preset values except that you prefer a higher compression level, you can do so as follows:
    1. In Fleet, open the **Settings** tab.
    2. In the **Outputs** section, select **Add output** to create a new output, or select the edit icon to edit an existing output.
    3. In the **Add new output** or the **Edit output** flyout, set **Performance tuning** to `Custom`.
    4. Refer to the list of [performance tuning preset values](#es-output-settings-performance-tuning-settings), and add the settings you prefer into the **Advanced YAML configuration** field. For the `balanced` presets, the yaml configuration would be as shown:
    ```yaml
    bulk_max_size: 1600
    worker: 1
    queue.mem.events: 3200
    queue.mem.flush.min_events: 1600
    queue.mem.flush.timeout: 10s
    compression_level: 1
    idle_connection_timeout: 3s
    ```
    1. Adjust any settings as preferred. For example, you can update the `compression_level` setting to `4`.
       When you create an Elastic Agent policy using this output, the output will use the balanced preset options except with the higher compression level, as specified.
  </definition>
  <definition term="Write to logs streams Elastic Cloud Serverless: Preview Elastic Stack: Preview since 9.2">
    When this setting is on, `logs` and `logs.*` are added to the output streams configuration in the agent policy using this output. Enabling this setting is only part of the process for allowing Elastic Agent to send data to [wired streams](/docs/solutions/observability/streams/streams#streams-wired-streams). For additional required steps, refer to [Ship data to streams > Fleet](/docs/solutions/observability/streams/wired-streams#streams-wired-streams-ship).
  </definition>
</definitions>


## Advanced YAML configuration

<definitions>
  <definition term="allow_older_versions">
    Allow Elastic Agent to connect and send output to an Elasticsearch instance that is running an earlier version than the agent version.
    This setting does not affect Elastic Agent's ability to connect to Fleet Server. Fleet Server will not accept a connection from an agent at a later major or minor version. It will accept a connection from an agent at a later patch version. For example, an Elastic Agent at version 8.14.3 can connect to a Fleet Server on version 8.14.0, but an agent at version 8.15.0 or later is not able to connect.
    **Default:** `true`
  </definition>
  <definition term="backoff.init">
    (string) The number of seconds to wait before trying to reconnect to Elasticsearch after a network error. After waiting `backoff.init` seconds, Elastic Agent tries to reconnect. If the attempt fails, the backoff timer is increased exponentially up to `backoff.max`. After a successful connection, the backoff timer is reset.
    **Default:** `1s`
  </definition>
  <definition term="backoff.max">
    (string) The maximum number of seconds to wait before attempting to connect to Elasticsearch after a network error.
    **Default:** `60s`
  </definition>
  <definition term="bulk_max_size">
    (int) The maximum number of events to bulk in a single Elasticsearch bulk API index request.
    Events can be collected into batches. Elastic Agent will split batches larger than `bulk_max_size` into multiple batches.
    Specifying a larger batch size can improve performance by lowering the overhead of sending events. However big batch sizes can also increase processing times, which might result in API errors, killed connections, timed-out publishing requests, and, ultimately, lower throughput.
    Setting `bulk_max_size` to values less than or equal to 0 turns off the splitting of batches. When splitting is disabled, the queue decides on the number of events to be contained in a batch.
    **Default:** `1600`
  </definition>
  <definition term="compression_level">
    (int) The gzip compression level. Set this value to `0` to disable compression. The compression level must be in the range of `1` (best speed) to `9` (best compression).
    Increasing the compression level reduces network usage but increases CPU usage.
  </definition>
  <definition term="max_retries">
    (int) The number of times to retry publishing an event after a publishing failure. After the specified number of retries, the events are typically dropped.
    Set `max_retries` to a value less than 0 to retry until all events are published.
    **Default:** `3`
  </definition>
  <definition term="queue.mem.events">
    The number of events the queue can store. This value should be evenly divisible by the smaller of `queue.mem.flush.min_events` or `bulk_max_size` to avoid sending partial batches to the output.
    **Default:** `3200 events`
  </definition>
  <definition term="queue.mem.flush.min_events">
    `flush.min_events` is a legacy parameter, and new configurations should prefer to control batch size with `bulk_max_size`. As of 8.13, there is never a performance advantage to limiting batch size with `flush.min_events` instead of `bulk_max_size`
    **Default:** `1600 events`
  </definition>
  <definition term="queue.mem.flush.timeout">
    (int) The maximum wait time for `queue.mem.flush.min_events` to be fulfilled. If set to 0s, events are available to the output immediately.
    **Default:** `10s`
  </definition>
  <definition term="timeout">
    (string) The HTTP request timeout in seconds for the Elasticsearch request.
    **Default:** `90s`
  </definition>
  <definition term="worker">
    (int) The number of workers per configured host publishing events. Example: If you have two hosts and three workers, in total six workers are started (three for each host).
    **Default:** `1`
  </definition>
  <definition term="status_reporting.enabled">
    (boolean) Whether status reporting is enabled for this output. When disabled, the output does not change its health status if there is a connectivity problem.
    **Default:** `true`
  </definition>
</definitions>


## Performance tuning settings


| Configuration                | Balanced | Optimized for Throughput | Optimized for Scale | Optimized for Latency |
|------------------------------|----------|--------------------------|---------------------|-----------------------|
| `bulk_max_size`              | 1600     | 1600                     | 1600                | 50                    |
| `worker`                     | 1        | 4                        | 1                   | 1                     |
| `queue.mem.events`           | 3200     | 12800                    | 3200                | 4100                  |
| `queue.mem.flush.min_events` | 1600     | 1600                     | 1600                | 2050                  |
| `queue.mem.flush.timeout`    | 10       | 5                        | 20                  | 1                     |
| `compression_level`          | 1        | 1                        | 1                   | 1                     |
| `idle_connection_timeout`    | 3        | 15                       | 1                   | 60                    |

For descriptions of each setting, refer to [Advanced YAML configuration](#es-output-settings-yaml-config). For the  `queue.mem.events`, `queue.mem.flush.min_events` and `queue.mem.flush.timeout` settings, refer to the [internal queue configuration settings](https://www.elastic.co/docs/reference/beats/filebeat/configuring-internal-queue) in the Filebeat documentation.
`Balanced` represents the new default setting (out of the box behavior). Relative to `Balanced`, `Optimized for throughput` setting will improve EPS by 4 times, `Optimized for Scale` will perform on par and `Optimized for Latency` will show a 20% degredation in EPS (Events Per Second). These relative performance numbers were calculated from a performance testbed which operates in a controlled setting ingesting a large log file.
As mentioned, the `custom` preset allows you to input your own set of parameters for a finer tuning of performance. The following table is a summary of a few data points and how the resulting EPS compares to the `Balanced` setting mentioned above.
These presets apply only to agents on version 8.12.0 or later.

| worker | bulk_max_size | queue.mem.events | queue.mem.flush.min_events | queue.mem.flush.timeout | idle_connection_timeout | Relative EPS |
|--------|---------------|------------------|----------------------------|-------------------------|-------------------------|--------------|
| 1      | 1600          | 3200             | 1600                       | 5                       | 15                      | 1x           |
| 1      | 2048          | 4096             | 2048                       | 5                       | 15                      | 1x           |
| 1      | 4096          | 8192             | 4096                       | 5                       | 15                      | 1x           |
| 2      | 1600          | 6400             | 1600                       | 5                       | 15                      | 2x           |
| 2      | 2048          | 8192             | 2048                       | 5                       | 15                      | 2x           |
| 2      | 4096          | 16384            | 4096                       | 5                       | 15                      | 2x           |
| 4      | 1600          | 12800            | 1600                       | 5                       | 15                      | 3.6x         |
| 4      | 2048          | 16384            | 2048                       | 5                       | 15                      | 3.6x         |
| 4      | 4096          | 32768            | 4096                       | 5                       | 15                      | 3.6x         |
| 8      | 1600          | 25600            | 1600                       | 5                       | 15                      | 5.3x         |
| 8      | 2048          | 32768            | 2048                       | 5                       | 15                      | 5.1x         |
| 8      | 4096          | 65536            | 4096                       | 5                       | 15                      | 5.2x         |
| 16     | 1600          | 51200            | 1600                       | 5                       | 15                      | 5.3x         |
| 16     | 2048          | 65536            | 2048                       | 5                       | 15                      | 5.2x         |
| 16     | 4096          | 131072           | 4096                       | 5                       | 15                      | 5.3x         |