Elasticsearch

Send logs to Elasticsearch (including Amazon OpenSearch Service)

The es output plugin, allows to ingest your records into an 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
compress	Set payload compression mechanism. Option available is 'gzip'
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.	512KB
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.
AWS_Auth	Enable AWS Sigv4 Authentication for Amazon OpenSearch Service	Off
AWS_Region	Specify the AWS region for Amazon OpenSearch Service
AWS_STS_Endpoint	Specify the custom sts endpoint to be used with STS API for Amazon OpenSearch Service
AWS_Role_ARN	AWS IAM Role to assume to put records to your Amazon cluster
AWS_External_ID	External ID for the AWS IAM Role specified with aws_role_arn
AWS_Service_Name	Service name to be used in AWS Sigv4 signature. For integration with Amazon OpenSearch Serverless, set to aoss. See the FAQ section on Amazon OpenSearch Serverless for more information.	es
AWS_Profile	AWS profile name	default
Cloud_ID	If you are using Elastic's Elasticsearch Service you can specify the cloud_id of the cluster running. The Cloud ID string has the format <deployment_name>:<base64_info>. Once decoded, the base64_info string has the format <deployment_region>$<elasticsearch_hostname>$<kibana_hostname>.
Cloud_Auth	Specify the credentials to use to connect to Elastic's Elasticsearch Service running on Elastic Cloud
HTTP_User	Optional username credential for Elastic X-Pack access
HTTP_Passwd	Password for user defined in HTTP_User
Index	Index name	fluent-bit
Type	Type name	_doc
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_Prefix_Key	When included: the value of the key in the record will be evaluated as key reference and overrides Logstash_Prefix for index generation. If the key/value is not found in the record then the Logstash_Prefix option will act as a fallback. The parameter is expected to be a record accessor.
Logstash_Prefix_Separator	Set a separator between logstash_prefix and date.	-
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
Time_Key_Nanos	When Logstash_Format is enabled, enabling this property sends nanosecond precision timestamps.	Off
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
Id_Key	If set, _id will be the value of the key from incoming record and Generate_ID option is ignored.
Write_Operation	The write_operation can be any of: create (default), index, update, upsert.	create
Replace_Dots	When enabled, replace field name dots with underscore, required by Elasticsearch 2.0-2.3.	Off
Trace_Output	Print all elasticsearch API request payloads to stdout (for diag only)	Off
Trace_Error	If elasticsearch return an error, print the elasticsearch API request and response (for diag only)	Off
Current_Time_Index	Use current time for index generation instead of message record	Off
Suppress_Type_Name	When enabled, mapping types is removed and Type option is ignored. If using Elasticsearch 8.0.0 or higher - it no longer supports mapping types, so it shall be set to On.	Off
Workers	Enables dedicated thread(s) for this output. Default value is set since version 1.8.13. For previous versions is 0.	2

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 TLS/SSL, for more details about the properties available and general configuration, please refer to the TLS/SSL section.

write_operation

The write_operation can be any of:

Operation	Description
create (default)	adds new data - if the data already exists (based on its id), the op is skipped.
index	new data is added while existing data (based on its id) is replaced (reindexed).
update	updates existing data (based on its id). If no data is found, the op is skipped.
upsert	known as merge or insert if the data does not exist, updates if the data exists (based on its id).

Please note, Id_Key or Generate_ID is required in update, and upsert scenario.

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:

es://host:port/index/type

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

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

which is similar to do:

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

Configuration File

In your main configuration file append the following Input & Output sections. You can visualize this configuration here

[INPUT]
    Name  cpu
    Tag   cpu

[OUTPUT]
    Name  es
    Match *
    Host  192.168.2.3
    Port  9200
    Index my_index
    Type  my_type

example configuration visualization from calyptia

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:

{"cpu0.p_cpu"=>17.000000}

becomes

{"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.

[OUTPUT]
    Name  es
    Match foo.*
    Index search
    Type  type1

[OUTPUT]
    Name  es
    Match bar.*
    Index search
    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.

Elasticsearch rejects requests saying "Document mapping type name can't start with '_'"

Fluent Bit v1.5 changed the default mapping type from flb_type to _doc, which matches the recommendation from Elasticsearch from version 6.2 forwards (see commit with rationale). This doesn't work in Elasticsearch versions 5.6 through 6.1 (see Elasticsearch discussion and fix). Ensure you set an explicit map (such as doc or flb_type) in the configuration, as seen on the last line:

[OUTPUT]
    Name  es
    Match *
    Host  vpc-test-domain-ke7thhzoo7jawsrhmm6mb7ite7y.us-west-2.es.amazonaws.com
    Port  443
    Index my_index
    AWS_Auth On
    AWS_Region us-west-2
    tls   On
    Type  doc

Fluent Bit + Amazon OpenSearch Service

The Amazon OpenSearch Service adds an extra security layer where HTTP requests must be signed with AWS Sigv4. Fluent Bit v1.5 introduced full support for Amazon OpenSearch Service with IAM Authentication.

See here for details on how AWS credentials are fetched.

Example configuration:

[OUTPUT]
    Name  es
    Match *
    Host  vpc-test-domain-ke7thhzoo7jawsrhmm6mb7ite7y.us-west-2.es.amazonaws.com
    Port  443
    Index my_index
    Type  my_type
    AWS_Auth On
    AWS_Region us-west-2
    tls     On

Notice that the Port is set to 443, tls is enabled, and AWS_Region is set.

Fluent Bit + Elastic Cloud

Fluent Bit supports connecting to Elastic Cloud providing just the cloud_id and the cloud_auth settings. cloud_auth uses the elastic user and password provided when the cluster was created, for details refer to the Cloud ID usage page.

Example configuration:

[OUTPUT]
    Name es
    Include_Tag_Key true
    Tag_Key tags
    tls On
    tls.verify Off
    Suppress_Type_Name On
    cloud_id elastic-obs-deployment:ZXVybxxxxxxxxxxxg==
    cloud_auth elastic:2vxxxxxxxxYV

Validation Failed: 1: an id must be provided if version type or value are set

Since v1.8.2, Fluent Bit started using create method (instead of index) for data submission. This makes Fluent Bit compatible with Datastream introduced in Elasticsearch 7.9.

If you see action_request_validation_exception errors on your pipeline with Fluent Bit >= v1.8.2, you can fix it up by turning on Generate_ID as follows:

[OUTPUT]
    Name es
    Match *
    Host  192.168.12.1
    Generate_ID on

Action/metadata contains an unknown parameter type

Elastic Cloud is now on version 8 so the type option must be removed by setting Suppress_Type_Name On as indicated above.

Without this you will see errors like:

{"error":{"root_cause":[{"type":"illegal_argument_exception","reason":"Action/metadata line [1] contains an unknown parameter [_type]"}],"type":"illegal_argument_exception","reason":"Action/metadata line [1] contains an unknown parameter [_type]"},"status":400}

Logstash_Prefix_Key

The following snippet demonstrates using the namespace name as extracted by the kubernetes filter as logstash prefix:

[OUTPUT]
    Name es
    Match *
    # ...
    Logstash_Prefix logstash
    Logstash_Prefix_Key $kubernetes["namespace_name"]
    # ...

For records that do nor have the field kubernetes.namespace_name, the default prefix, logstash will be used.