Logstash output settingsedit

Specify these settings to send data over a secure connection to Logstash. You must also configure a Logstash pipeline that reads encrypted data from Elastic Agents and sends the data to Elasticsearch. Follow the in-product steps to configure the Logstash pipeline.

In the Fleet Output settings, make sure that the Logstash output type is selected.

Before using the Logstash output, you need to make sure that for any integrations that have been added to your Elastic Agent policy, the integration assets have been installed on the destination cluster. Refer to Install and uninstall Elastic Agent integration assets for the steps to add integration assets.

To learn how to generate certificates, refer to Configure SSL/TLS for the Logstash output.

Logstash hosts

The addresses your Elastic Agents will use to connect to Logstash. Use the format host:port. Click add row to specify additional Logstash addresses.

Examples:

  • 192.0.2.0:5044
  • mylogstashhost:5044

Refer to the Fleet Server documentation for default ports and other configuration details.

Server SSL certificate authorities

The CA certificate to use to connect to Logstash. This is the CA used to generate the certificate and key for Logstash. Copy and paste in the full contents for the CA certificate.

This setting is optional.

Client SSL certificate

The certificate generated for the client. Copy and paste in the full contents of the certificate. This is the certificate that all the agents will use to connect to Logstash.

In cases where each client has a unique certificate, the local path to that certificate can be placed here. The agents will pick the certificate in that location when establishing a connection to Logstash.

Client SSL certificate key

The private key generated for the client. This must be in PKCS 8 key. Copy and paste in the full contents of the certificate key. This is the certificate key that all the agents will use to connect to Logstash.

In cases where each client has a unique certificate key, the local path to that certificate key can be placed here. The agents will pick the certificate key in that location when establishing a connection to Logstash.

To prevent unauthorized access the certificate key is stored as a secret value. While secret storage is recommended, you can choose to override this setting and store the key as plain text in the agent policy definition. Secret storage requires Fleet Server version 8.12 or higher.

Note that this setting can also be stored as a secret value or as plain text for preconfigured outputs. See Preconfiguration settings in the Kibana Guide to learn more.

Proxy

Select a proxy URL for Elastic Agent to connect to Logstash. To learn about proxy configuration, refer to Using a proxy server with Elastic Agent and Fleet.

Advanced YAML configuration

YAML settings that will be added to the Logstash 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 for descriptions of the available settings.

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.

Output to Logstash is not supported for agent integrations in a policy used by Fleet Server or APM.

Make this output the default for agent monitoring

When this setting is on, Elastic Agents use this output to send agent monitoring data if no other output is set in the agent policy.

Output to Logstash is not supported for agent monitoring in a policy used by Fleet Server or APM.

Advanced YAML configurationedit

Setting Description

backoff.init

(string) The number of seconds to wait before trying to reconnect to Logstash 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

backoff.max

(string) The maximum number of seconds to wait before attempting to connect to Elasticsearch after a network error.

Default: 60s

bulk_max_size

(int) The maximum number of events to bulk in a single Logstash 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.

Set this value to 0 to turn off the splitting of batches. When splitting is turned off, the queue determines the number of events to be contained in a batch.

Default: 2048

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.

escape_html

(boolean) Configures escaping of HTML in strings. Set to true to enable escaping.

Default: false

index

(string) The index root name to write events to.

loadbalance

If true and multiple Logstash hosts are configured, the output plugin load balances published events onto all Logstash hosts. If false, the output plugin sends all events to one host (determined at random) and switches to another host if the selected one becomes unresponsive.

Default: false

Example:

outputs:
  default:
    type: logstash
    hosts: ["localhost:5044", "localhost:5045"]
    loadbalance: true

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

pipelining

(int) The number of batches to send asynchronously to Logstash while waiting for an ACK from Logstash. The output becomes blocking after the specified number of batches are written. Specify 0 to turn off pipelining.

Default: 2

proxy_use_ local_resolver

(boolean) Determines whether Logstash hostnames are resolved locally when using a proxy. If false and a proxy is used, name resolution occurs on the proxy server.

Default: false

queue.mem.events

The number of events the queue can store. This value should be evenly divisible by queue.mem.flush.min_events to avoid sending partial batches to the output.

Default: 3200 events

queue.mem.flush.min_events

The minimum number of events required for publishing. If this value is set to 0 or 1, events are available to the output immediately. If this value is greater than 1 the output must wait for the queue to accumulate this minimum number of events or for queue.mem.flush.timeout to expire before publishing. When greater than 1 this value also defines the maximum possible batch that can be sent by the output.

Default: 1600 events

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

slow_start

(boolean) If true, only a subset of events in a batch of events is transferred per transaction. The number of events to be sent increases up to bulk_max_size if no error is encountered. On error, the number of events per transaction is reduced again.

Default: false

timeout

(string) The number of seconds to wait for responses from the Logstash server before timing out.

Default: 30s

ttl

(string) Time to live for a connection to Logstash after which the connection will be reestablished. This setting is useful when Logstash hosts represent load balancers. Because connections to Logstash hosts are sticky, operating behind load balancers can lead to uneven load distribution across instances. Specify a TTL on the connection to achieve equal connection distribution across instances.

Default: 0 (turns off the feature)

The ttl option is not yet supported on an asynchronous Logstash client (one with the pipelining option set).

worker

(int) The number of workers per configured host publishing events. This is best used with load balancing mode enabled. Example: If you have two hosts and three workers, in total six workers are started (three for each host).

Default: 1