Configure the Elasticsearch outputedit

This documentation refers to configuring the standalone (legacy) APM Server. This method of running APM Server will be deprecated and removed in a future release. Please consider upgrading to Fleet and the APM integration.

The Elasticsearch output sends events directly to Elasticsearch using the Elasticsearch HTTP API.

Example configuration:

  hosts: ["https://myEShost:9200"] 

To enable SSL, add https to all URLs defined under hosts.

When sending data to a secured cluster through the elasticsearch output, APM Server can use any of the following authentication methods:

  • Basic authentication credentials (username and password).
  • Token-based (API key) authentication.
  • Public Key Infrastructure (PKI) certificates.

Basic authentication:

  hosts: ["https://myEShost:9200"]
  username: "apm_writer"
  password: "YOUR_PASSWORD"

API key authentication:

  hosts: ["https://myEShost:9200"]
  api_key: "KnR6yE41RrSowb0kQ0HWoA"

PKI certificate authentication:

  hosts: ["https://myEShost:9200"]
  ssl.certificate: "/etc/pki/client/cert.pem"
  ssl.key: "/etc/pki/client/cert.key"

See Secure communication with Elasticsearch for details on each authentication method.


This output works with all compatible versions of Elasticsearch. See the Elastic Support Matrix.

Configuration optionsedit

You can specify the following options in the elasticsearch section of the apm-server.yml config file:


The enabled config is a boolean setting to enable or disable the output. If set to false, the output is disabled.

The default value is true.


The list of Elasticsearch nodes to connect to. The events are distributed to these nodes in round robin order. If one node becomes unreachable, the event is automatically sent to another node. Each Elasticsearch node can be defined as a URL or IP:PORT. For example:, or If no port is specified, 9200 is used.

When a node is defined as an IP:PORT, the scheme and path are taken from the protocol and path config options.

  hosts: ["", ""] 
  protocol: https
  path: /elasticsearch

In the previous example, the Elasticsearch nodes are available at and


The gzip compression level. Setting this value to 0 disables compression. The compression level must be in the range of 1 (best speed) to 9 (best compression).

Increasing the compression level will reduce the network usage but will increase the CPU usage.

The default value is 0.


Configure escaping of HTML in strings. Set to true to enable escaping.

The default value is false.


Instead of using a username and password, you can use API keys to secure communication with Elasticsearch. The value must be the ID of the API key and the API key joined by a colon: id:api_key.

See Grant access using API keys for more information.


The basic authentication username for connecting to Elasticsearch.

This user needs the privileges required to publish events to Elasticsearch. To create a user like this, see Create a writer user.


The basic authentication password for connecting to Elasticsearch.


Dictionary of HTTP parameters to pass within the URL with index operations.


The name of the protocol Elasticsearch is reachable on. The options are: http or https. The default is http. However, if you specify a URL for hosts, the value of protocol is overridden by whatever scheme you specify in the URL.


An HTTP path prefix that is prepended to the HTTP API calls. This is useful for the cases where Elasticsearch listens behind an HTTP reverse proxy that exports the API under a custom prefix.


Custom HTTP headers to add to each request created by the Elasticsearch output. Example:

  X-My-Header: Header contents

It is possible to specify multiple header values for the same header name by separating them with a comma.


The URL of the proxy to use when connecting to the Elasticsearch servers. The value may be either a complete URL or a "host[:port]", in which case the "http" scheme is assumed. If a value is not specified through the configuration file then proxy environment variables are used. See the Go documentation for more information about the environment variables.


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.

The default is 3.


The bulk request size threshold, in bytes, before flushing to Elasticsearch. The value must have a suffix, e.g. "1MB". The default is 5MB.


The maximum duration to accumulate events for a bulk request before being flushed to Elasticsearch. The value must have a duration suffix, e.g. "5s". The default is 1s.


The number of seconds to wait before trying to reconnect to Elasticsearch after a network error. After waiting backoff.init seconds, APM Server 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. The default is 1s.


The maximum number of seconds to wait before attempting to connect to Elasticsearch after a network error. The default is 60s.


The HTTP request timeout in seconds for the Elasticsearch request. The default is 90.


Configuration options for SSL parameters like the certificate authority to use for HTTPS-based connections. If the ssl section is missing, the host CAs are used for HTTPS connections to Elasticsearch.

See the secure communication with Elasticsearch guide or SSL configuration reference for more information.


Configuration options for Kerberos authentication.

See Kerberos for more information.