Logstash Outputedit

Prerequisite: To use Logstash as an output, you must install and configure the Beats input plugin for Logstash.

The Logstash output sends the events directly to Logstash by using the lumberjack protocol, which runs over TCP. Logstash allows for additional processing and routing of generated events.

Here is an example of how to configure Heartbeat to use Logstash:

output.logstash:
  hosts: ["localhost:5044"]

Accessing Metadata Fieldsedit

Every event sent to Logstash contains the following metadata fields that you can use in Logstash for indexing and filtering:

{
    ...
    "@metadata": { 
      "beat": "heartbeat", 
      "type": "<event type>" 
    }
}

Heartbeat uses the @metadata field to send metadata to Logstash. The contents of the @metadata field only exist in Logstash and are not part of any events sent from Logstash. See the Logstash documentation for more about the @metadata field.

The default is heartbeat. To change this value, set the index option in the Heartbeat config file.

The value of type varies depending on the event type.

You can access this metadata from within the Logstash config file to set values dynamically based on the contents of the metadata.

For example, the following Logstash configuration file for versions 2.x and 5.x sets Logstash to use the index and document type reported by Beats for indexing events into Elasticsearch:

input {
  beats {
    port => 5044
  }
}

output {
  elasticsearch {
    hosts => ["http://localhost:9200"]
    index => "%{[@metadata][beat]}-%{+YYYY.MM.dd}" 
    document_type => "%{[@metadata][type]}" 
  }
}

%{[@metadata][beat]} sets the first part of the index name to the value of the beat metadata field, and %{+YYYY.MM.dd} sets the second part of the name to a date based on the Logstash @timestamp field. For example: heartbeat-2017.03.29.

%{[@metadata][type]} sets the document type based on the value of the type metadata field.

Events indexed into Elasticsearch with the Logstash configuration shown here will be similar to events directly indexed by Beats into Elasticsearch.

Compatibilityedit

This output works with all compatible versions of Logstash. See "Supported Beats Versions" in the Elastic Support Matrix.

Logstash Output Optionsedit

You can specify the following options in the logstash section of the heartbeat.yml config file:

enablededit

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.

hostsedit

The list of known Logstash servers to connect to. If load balancing is disabled, but mutliple hosts are configured, one host is selected randomly (there is no precedence). If one host becomes unreachable, another one is selected randomly.

All entries in this list can contain a port number. If no port number is given, the value specified for port is used as the default port number.

compression_leveledit

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 3.

workeredit

The number of workers per configured host publishing events to Logstash. This is best used with load balancing mode enabled. Example: If you have 2 hosts and 3 workers, in total 6 workers are started (3 for each host).

loadbalanceedit

If set to true and multiple Logstash hosts are configured, the output plugin load balances published events onto all Logstash hosts. If set to false, the output plugin sends all events to only one host (determined at random) and will switch to another host if the selected one becomes unresponsive. The default value is false.

output.logstash:
  hosts: ["localhost:5044", "localhost:5045"]
  loadbalance: true
  index: heartbeat

pipeliningedit

Configures number of batches to be send asynchronously to logstash while waiting for ACK from logstash. Output only becomes blocking once number of pipelining batches have been written. Pipelining is disabled if a values of 0 is configured. The default value is 0.

portedit

Warning

Deprecated in 5.0.0.

The default port to use if the port number is not given in hosts. The default port number is 10200.

proxy_urledit

The URL of the SOCKS5 proxy to use when connecting to the Logstash servers. The value must be a URL with a scheme of socks5://. The protocol used to communicate to Logstash is not based on HTTP so a web-proxy cannot be used.

If the SOCKS5 proxy server requires client authentication, then a username and password can be embedded in the URL as shown in the example.

When using a proxy, hostnames are resolved on the proxy server instead of on the client. You can change this behavior by setting the proxy_use_local_resolver option.

output.logstash:
  hosts: ["remote-host:5044"]
  proxy_url: socks5://user:password@socks5-proxy:2233

proxy_use_local_resolveredit

The proxy_use_local_resolver option determines if Logstash hostnames are resolved locally when using a proxy. The default value is false which means that when a proxy is used the name resolution occurs on the proxy server.

indexedit

The index root name to write events to. The default is the Beat name. For example "heartbeat" generates "[heartbeat-]YYYY.MM.DD" indexes (for example, "heartbeat-2015.04.26").

ssledit

Configuration options for SSL parameters like the root CA for Logstash connections. See SSL for more information. To use SSL, you must also configure the Beats input plugin for Logstash to use SSL/TLS.

timeoutedit

The number of seconds to wait for responses from the Logstash server before timing out. The default is 30 (seconds).

max_retriesedit

The number of times to retry publishing an event after a publishing failure. After the specified number of retries, the events are typically dropped. Some Beats, such as Filebeat, ignore the max_retries setting and retry until all events are published.

Set max_retries to a value less than 0 to retry until all events are published.

The default is 3.

bulk_max_sizeedit

The maximum number of events to bulk in a single Logstash request. The default is 2048.

If the Beat sends single events, the events are collected into batches. If the Beat publishes a large batch of events (larger than the value specified by bulk_max_size), the batch is split.

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 disables buffering in libbeat. When buffering is disabled, Beats that publish single events (such as Packetbeat) send each event directly to Elasticsearch. Beats that publish data in batches (such as Filebeat) send events in batches based on the spooler size.