Elasticsearch

The es output plugin, allows to ingest your records into a Elasticsearch database. The following instructions assumes that you have a fully operational Elasticsearch service running in your environment.

Configuration Parameters

Key Description default
Host IP address or hostname of the target Elasticsearch instance 127.0.0.1
Port TCP port of the target Elasticsearch instance 9200
Path Elasticsearch accepts new data on HTTP query path “/_bulk”. But it is also possible to serve Elasticsearch behind a reverse proxy on a subpath. This option defines such path on the fluent-bit side. It simply adds a path prefix in the indexing HTTP POST URI. Empty string
Buffer_Size Specify the buffer size used to read the response from the Elasticsearch HTTP service. This option is useful for debugging purposes where is required to read full responses, note that response size grows depending of the number of records inserted. To set an unlimited amount of memory set this value to False, otherwise the value must be according to the Unit Size specification. 4KB
Pipeline Newer versions of Elasticsearch allows to setup filters called pipelines. This option allows to define which pipeline the database should use. For performance reasons is strongly suggested to do parsing and filtering on Fluent Bit side, avoid pipelines.
HTTP_User Optional username credential for Elastic X-Pack access
HTTP_Passwd Password for user defined in HTTP_User
Index Index name fluentbit
Type Type name flb_type
Logstash_Format Enable Logstash format compatibility. This option takes a boolean value: True/False, On/Off Off
Logstash_Prefix When Logstash_Format is enabled, the Index name is composed using a prefix and the date, e.g: If Logstash_Prefix is equals to ‘mydata’ your index will become ‘mydata-YYYY.MM.DD’. The last string appended belongs to the date when the data is being generated. logstash
Logstash_DateFormat Time format (based on strftime) to generate the second part of the Index name. %Y.%m.%d
Time_Key When Logstash_Format is enabled, each record will get a new timestamp field. The Time_Key property defines the name of that field. @timestamp
Time_Key_Format When Logstash_Format is enabled, this property defines the format of the timestamp. %Y-%m-%dT%H:%M:%S
Include_Tag_Key When enabled, it append the Tag name to the record. Off
Tag_Key When Include_Tag_Key is enabled, this property defines the key name for the tag. _flb-key
Generate_ID When enabled, generate _id for outgoing records. This prevents duplicate records when retrying ES. Off
Replace_Dots When enabled, replace field name dots with underscore, required by Elasticsearch 2.0-2.3. Off
Trace_Output When enabled print the elasticsearch API calls to stdout (for diag only) Off
Trace_Error When enabled print the elasticsearch API calls to stdout when elasticsearch returns an error Off
Current_Time_Index Use current time for index generation instead of message record Off
Logstash_Prefix_Key Prefix keys with this string

The parameters index and type can be confusing if you are new to Elastic, if you have used a common relational database before, they can be compared to the database and table concepts. Also see the FAQ below

TLS / SSL

Elasticsearch output plugin supports TTL/SSL, for more details about the properties available and general configuration, please refer to the TLS/SSL section.

Getting Started

In order to insert records into a Elasticsearch service, you can run the plugin from the command line or through the configuration file:

Command Line

The es plugin, can read the parameters from the command line in two ways, through the -p argument (property) or setting them directly through the service URI. The URI format is the following:

  1. es://host:port/index/type

Using the format specified, you could start Fluent Bit through:

  1. $ fluent-bit -i cpu -t cpu -o es://192.168.2.3:9200/my_index/my_type \
  2.     -o stdout -m '*'

which is similar to do:

  1. $ fluent-bit -i cpu -t cpu -o es -p Host=192.168.2.3 -p Port=9200 \
  2.     -p Index=my_index -p Type=my_type -o stdout -m '*'

Configuration File

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

  1. [INPUT]
  2.     Name  cpu
  3.     Tag   cpu
  5. [OUTPUT]
  6.     Name  es
  7.     Match *
  8.     Host  192.168.2.3
  9.     Port  9200
  10.     Index my_index
  11.     Type  my_type

About Elasticsearch field names

Some input plugins may generate messages where the field names contains dots, since Elasticsearch 2.0 this is not longer allowed, so the current es plugin replaces them with an underscore, e.g:

  1. {"cpu0.p_cpu"=>17.000000}

becomes

  1. {"cpu0_p_cpu"=>17.000000}

FAQ

Elasticsearch rejects requests saying “the final mapping would have more than 1 type”

Since Elasticsearch 6.0, you cannot create multiple types in a single index. This means that you cannot set up your configuration as below anymore.

  1. [OUTPUT]
  2.     Name  es
  3.     Match foo.*
  4.     Index search
  5.     Type  type1
  7. [OUTPUT]
  8.     Name  es
  9.     Match bar.*
  10.     Index search
  11.     Type  type2

If you see an error message like below, you’ll need to fix your configuration to use a single type on each index.

Rejecting mapping update to [search] as the final mapping would have more than 1 type

For details, please read the official blog post on that issue.

Fluent Bit + AWS Elasticsearch

AWS Elasticsearch adds an extra security layer where the HTTP requests we must be signed with AWS Signv4, as of Fluent Bit v1.3 this is not yet supported. At the end of January 2020 with the release of Fluent Bit v1.4 we are adding such feature (among integration with other AWS Services ;) )

As a workaround, you can use the following tool as a proxy:

More details about this AWS requirement can be found here: