# 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 fully qualified domain name. 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](https://docs.fluentbit.io/manual/4.1/administration/multithreading#inputs).      | `false`       |

The Elasticsearch cluster uses "sniffing" to optimize the connections between its cluster and clients, which means it builds its cluster and dynamically generate a connection list. The `hostname` will be used for sniffing information and this is handled by the sniffing endpoint.

## Get 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:

```shell
fluent-bit -i elasticsearch -p port=9200 -o stdout
```

### Configuration file

In your configuration file append the following:

{% tabs %}
{% tab title="fluent-bit.yaml" %}

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

  outputs:
    - name: stdout
      match: '*'
```

{% endtab %}

{% tab title="fluent-bit.conf" %}

```
[INPUT]
  name   elasticsearch
  listen 0.0.0.0
  port   9200

[OUTPUT]
  name  stdout
  match *
```

{% endtab %}
{% endtabs %}

As described previously, the plugin will handle ingested Bulk API requests. For large bulk ingestion, you might have to increase buffer size using the `buffer_max_size` and `buffer_chunk_size` parameters:

{% tabs %}
{% tab title="fluent-bit.yaml" %}

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

  outputs:
    - name: stdout
      match: '*'
```

{% endtab %}

{% tab title="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 *
```

{% endtab %}
{% endtabs %}

#### Ingesting from beats series

Ingesting from beats series agents is also supported. For example, [Filebeats](https://www.elastic.co/beats/filebeat), [Metricbeat](https://www.elastic.co/beats/metricbeat), and [Winlogbeat](https://www.elastic.co/beats/winlogbeat) are able to ingest their collected data through this plugin.

The Fluent Bit node information is returning as Elasticsearch 8.0.0.

Users must specify the following configurations on their beats configurations:

```yaml
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:

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