Elasticsearch

The elasticsearch input plugin handles both Elasticsearch and OpenSearch Bulk API requests.

Configuration Parameters

The plugin supports the following configuration parameters:

Key	Description	Default value
buffer_max_size	Set the maximum size of buffer.	4M
buffer_chunk_size	Set the buffer chunk size.	512K
tag_key	Specify a key name for extracting as a tag.	NULL
meta_key	Specify a key name for meta information.	"@meta"
hostname	Specify hostname or FQDN. This parameter can be used for "sniffing" (auto-discovery of) cluster node information.	"localhost"
version	Specify Elasticsearch server version. This parameter is effective for checking a version of Elasticsearch/OpenSearch server version.	"8.0.0"
threaded	Indicates whether to run this input in its own thread.	false

Note: The Elasticsearch cluster uses "sniffing" to optimize the connections between its cluster and clients. Elasticsearch can build its cluster and dynamically generate a connection list which is called "sniffing". The hostname will be used for sniffing information and this is handled by the sniffing endpoint.

Getting Started

In order to start performing the checks, you can run the plugin from the command line or through the configuration file:

Command Line

From the command line you can configure Fluent Bit to handle Bulk API requests with the following options:

$ fluent-bit -i elasticsearch -p port=9200 -o stdout

Configuration File

In your main configuration file append the following Input & Output sections:

fluent-bit.conf

[INPUT]
    name elasticsearch
    listen 0.0.0.0
    port 9200

[OUTPUT]
    name stdout
    match *

fluent-bit.yaml

pipeline:
    inputs:
        - name: elasticsearch
          listen: 0.0.0.0
          port: 9200

    outputs:
        - name: stdout
          match: '*'

As described above, the plugin will handle ingested Bulk API requests. For large bulk ingestions, you may have to increase buffer size with buffer_max_size and buffer_chunk_size parameters:

fluent-bit.conf

[INPUT]
    name elasticsearch
    listen 0.0.0.0
    port 9200
    buffer_max_size 20M
    buffer_chunk_size 5M

[OUTPUT]
    name stdout
    match *

fluent-bit.yaml

pipeline:
    inputs:
        - name: elasticsearch
          listen: 0.0.0.0
          port: 9200
          buffer_max_size: 20M
          buffer_chunk_size: 5M

    outputs:
        - name: stdout
          match: '*'

Ingesting from beats series

Ingesting from beats series agents is also supported. For example, Filebeats, Metricbeat, and Winlogbeat are able to ingest their collected data through this plugin.

Note that Fluent Bit's node information is returning as Elasticsearch 8.0.0.

So, users have to specify the following configurations on their beats configurations:

output.elasticsearch:
  allow_older_versions: true
  ilm: false

For large log ingestion on these beat plugins, users might have to configure rate limiting on those beats plugins when Fluent Bit indicates that the application is exceeding the size limit for HTTP requests:

processors:
  - rate_limit:
      limit: "200/s"