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elasticsearch.md

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description
Send logs to Elasticsearch (including Amazon Elasticsearch Service)

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.
AWS_Auth Enable AWS Sigv4 Authentication for Amazon ElasticSearch Service Off
AWS_Region Specify the AWS region for Amazon ElasticSearch Service
AWS_STS_Endpoint Specify the custom sts endpoint to be used with STS API for Amazon ElasticSearch Service
AWS_Role_ARN AWS IAM Role to assume to put records to your Amazon ES cluster
AWS_External_ID External ID for the AWS IAM Role specified with aws_role_arn
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_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
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
Current_Time_Index Use current time for index generation instead of message record Off
Logstash_Prefix_Key When included: the value in the record that belongs to the key will be looked up and over-write the 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. Nested keys are not supported (if desired, you can use the nest filter plugin to remove nesting)

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:

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 config.calyptia.com

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 Elasticsearch Service

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

Fluent Bit supports sourcing AWS credentials from any of the standard sources (for example, an Amazon EKS IAM Role for a Service Account).

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.