Fluentd
1.0
1.0
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    • Install fluent-package
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    • Install by Ruby Gem
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    • Post Installation Guide
    • Obsolete Installation
      • Treasure Agent v4 (EOL) Installation
        • Install by RPM Package v4 (Red Hat Linux)
        • Install by DEB Package v4 (Debian/Ubuntu)
        • Install by .dmg Package v4 (macOS)
        • Install by .msi Installer v4 (Windows)
      • Treasure Agent v3 (EOL) Installation
        • Install by RPM Package v3 (Red Hat Linux)
        • Install by DEB Package v3 (Debian/Ubuntu)
        • Install by .dmg Package v3 (macOS)
        • Install by .msi Installer v3 (Windows)
  • Configuration
    • Config File Syntax
    • Config File Syntax (YAML)
    • Routing Examples
    • Config: Common Parameters
    • Config: Parse Section
    • Config: Buffer Section
    • Config: Format Section
    • Config: Extract Section
    • Config: Inject Section
    • Config: Transport Section
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    • Config: Service Discovery Section
  • Deployment
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  • Monitoring Fluentd
    • Overview
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  • Input Plugins
    • tail
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    • sample
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    • windows_eventlog
  • Output Plugins
    • file
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  • Filter Plugins
    • record_transformer
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    • stdout
  • Parser Plugins
    • regexp
    • apache2
    • apache_error
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    • ltsv
    • csv
    • tsv
    • json
    • msgpack
    • multiline
    • none
  • Formatter Plugins
    • out_file
    • json
    • ltsv
    • csv
    • msgpack
    • hash
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    • stdout
    • tsv
  • Buffer Plugins
    • memory
    • file
    • file_single
  • Storage Plugins
    • local
  • Service Discovery Plugins
    • static
    • file
    • srv
  • Metrics Plugins
    • local
  • How-to Guides
    • Stream Analytics with Materialize
    • Send Apache Logs to S3
    • Send Apache Logs to Minio
    • Send Apache Logs to Mongodb
    • Send Syslog Data to Graylog
    • Send Syslog Data to InfluxDB
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    • Data Analytics with Treasure Data
    • Data Collection with Hadoop (HDFS)
    • Simple Stream Processing with Fluentd
    • Stream Processing with Norikra
    • Stream Processing with Kinesis
    • Free Alternative To Splunk
    • Email Alerting like Splunk
    • How to Parse Syslog Messages
    • Cloud Data Logging with Raspberry Pi
  • Language Bindings
    • Java
    • Ruby
    • Python
    • Perl
    • PHP
    • Nodejs
    • Scala
  • Plugin Development
    • How to Write Input Plugin
    • How to Write Base Plugin
    • How to Write Buffer Plugin
    • How to Write Filter Plugin
    • How to Write Formatter Plugin
    • How to Write Output Plugin
    • How to Write Parser Plugin
    • How to Write Storage Plugin
    • How to Write Service Discovery Plugin
    • How to Write Tests for Plugin
    • Configuration Parameter Types
    • Upgrade Plugin from v0.12
  • Plugin Helper API
    • Plugin Helper: Child Process
    • Plugin Helper: Compat Parameters
    • Plugin Helper: Event Emitter
    • Plugin Helper: Event Loop
    • Plugin Helper: Extract
    • Plugin Helper: Formatter
    • Plugin Helper: Inject
    • Plugin Helper: Parser
    • Plugin Helper: Record Accessor
    • Plugin Helper: Server
    • Plugin Helper: Socket
    • Plugin Helper: Storage
    • Plugin Helper: Thread
    • Plugin Helper: Timer
    • Plugin Helper: Http Server
    • Plugin Helper: Service Discovery
  • Troubleshooting Guide
  • Appendix
    • Update from v0.12 to v1
    • td-agent v2 vs v3 vs v4
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On this page
  • Example Configuration
  • Plugin Helpers
  • Parameters
  • @type
  • tag
  • port
  • bind
  • source_hostname_key
  • source_address_key
  • message_length_limit
  • <transport> Section
  • <security> Section
  • <parse> Section
  • Code Example
  • Tips
  • How to Enable TLS Encryption
  • How to Enable TLS Mutual Authentication

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  1. Input Plugins

tcp

PreviousudpNextunix

Last updated 5 months ago

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The in_tcp Input plugin enables Fluentd to accept TCP payload.

It is included in Fluentd's core.

Don't use this plugin for receiving logs from Fluentd client libraries. Use in_forward for such cases.

Example Configuration

<source>
  @type tcp
  tag tcp.events # required
  <parse>
    @type regexp
    expression /^(?<field1>\d+):(?<field2>\w+)$/
  </parse>
  port 20001   # optional. 5170 by default
  bind 0.0.0.0 # optional. 0.0.0.0 by default
  delimiter "\n" # optional. "\n" (newline) by default
</source>

Example input:

$ echo '123456:awesome' | netcat 0.0.0.0 5170

Parsed result:

{"field1":"123456","field2":"awesome"}

Plugin Helpers

Parameters

@type

The value must be tcp.

tag

type
default
version

string

required parameter

0.14.0

The tag of output events.

port

type
default
version

integer

5170

0.14.0

The port to listen to.

bind

type
default
version

string

0.0.0.0 (all addresses)

0.14.0

The bind address to listen to.

source_hostname_key

type
default
version

string

nil (no adding hostname)

0.14.10

The field name of the client's hostname. If set, the client's hostname will be set to its key. The default is nil (no adding hostname).

With this configuration:

source_hostname_key client_host

The client's hostname is set to client_host field:

{
    ...
    "foo": "bar",
    "client_host": "client.hostname.org"
}

source_address_key

type
default
version

string

nil (no adding source address)

1.4.2

The field name for the client's IP address. If set, Fluentd automatically adds the remote address to each data record.

For example, if you have the following configuration:

<source>
  @type tcp
  source_address_key client_addr
  # ...
</source>

You will get something like below:

{
    ...
    "client_addr": "192.168.10.10"
    ...
}

message_length_limit

type
default
version

size

nil (no limit)

1.16.1

The maximum number of bytes for the message.

<transport> Section

type
default
available values
version

enum

tcp

tcp, tls

0.14.12

General configuration

linger_timeout

type
default
available transport type
version

integer

0

tcp, tls

1.14.6

The timeout (seconds) to set SO_LINGER.

The default value 0 is to send RST rather than FIN to avoid lots of connections sitting in TIME_WAIT on closing on non-Windows.

You can set positive value to send FIN on closing on non-Windows.

On Windows, Fluentd sends FIN without depending on this setting.

<source>
  @type tcp
  # other plugin parameters
  <transport tcp>
    linger_timeout 1
  </transport>
</source>

send_keepalive_packet

type
default
available transport type
version

bool

false

tcp, tls

1.16.0

Enable SO_KEEPALIVE on the underlying TCP sockets.

This is useful when you connect to Fluentd over firewalls or proxies and want to prevent connections from being closed automatically.

TLS configuration

<transport tls>
  cert_path /path/to/fluentd.crt
  # ...
</transport>

Without <transport tls>, in_tcp uses raw TCP.

<security> Section

required
multi
version

false

false

1.7.2

Adds <security>/<client> section to allow access by Host/IP/Network.

<client> Section

host

type
default
version

string

nil

1.7.2

The IP address or host name of the client.

This is exclusive with network.

network

type
default
version

string

nil

1.7.2

Network address specification.

This is exclusive with host.

<parse> Section

required
multi
version

true

false

0.14.10

in_tcp uses the parser plugin to parse the payload.

For more details:

Code Example

Here is a Ruby example to send an event to in_tcp:

require 'socket'

# This example uses json payload.
# In in_tcp configuration, need to configure "@type json" in "<parse>"
TCPSocket.open('127.0.0.1', 5170) do |s|
  s.write('{"k":"v1"}' + "\n")
  s.write('{"k":"v2"}' + "\n")
end

Tips

How to Enable TLS Encryption

in_tcp supports TLS transport.

Example:

<source>
  @type tcp
  port 5140
  bind 0.0.0.0
  <transport tls>
    ca_path /etc/pki/ca.pem
    cert_path /etc/pki/cert.pem
    private_key_path /etc/pki/key.pem
    private_key_passphrase PASSPHRASE
  </transport>
  tag tcp
</source>

How to Enable TLS Mutual Authentication

<source>
  @type tcp
  port 20001
  <transport tls>
    # ...
    client_cert_auth true
    ca_path /path/to/ca/cert
  </transport>
</source>

When this feature is enabled, Fluentd will check all the incoming requests for a client certificate signed by the trusted CA. Requests with an invalid client certificate will fail.

To check if mutual authentication is working properly, issue these commands:

$ openssl s_client -connect localhost:20001 \
  -key path/to/client.key \
  -cert path/to/client.crt \
  -CAfile path/to/ca.crt

If the connection gets established successfully, your setup is working fine.

Refer to the article for the basic structure and syntax of the configuration file.

For <parse>, see .

We have observed drastic performance improvements on Linux, with proper kernel parameter settings. If you have high-volume TCP traffic, follow instructions.

See .

This section is for setting TLS transport or some general transport configurations. See for all supported parameters.

See section for how to use and see for all supported parameters.

Fluentd supports (i.e. client certificate auth). If you want to use this feature, please set the client_cert_auth and ca_path options like this:

If this article is incorrect or outdated, or omits critical information, please . is an open-source project under . All components are available under the Apache 2 License.

Configuration File
Parse Section
Before Installing Fluentd
server
parser
extract
compat_parameters
Common Parameters
Config: Transport Section
Parser Plugin Overview
Parse Section Configurations
TLS mutual authentication
let us know
Fluentd
Cloud Native Computing Foundation (CNCF)
How to Enable TLS Encryption
Configuration Example