Config: Transport Section

Some Fluentd input, output, and filter plugins, that use server/http_server plugin helper, also support the <transport> section to specify how to handle the connections.

Transport Section Overview

The transport section must be under <match>, <source>, and <filter> sections. It specifies the transport protocol, version, and certificates.

# tcp
<transport tcp>
</transport>
# udp
<transport udp>
</transport>
# tls
<transport tls>
cert_path /path/to/fluentd.crt
private_key_path /path/to/fluentd.key
private_key_passphrase YOUR_PASSPHRASE
# ...
</transport>

Parameters

  • protocol [enum: tcp/udp/tls]

    • Default: tcp

TLS Setting

  • version: [enum: TLS1_1/TLS1_2/TLS1_3]

    • Default: TLSv1_2

  • min_version: [enum: TLS1_1/TLS1_2/TLS1_3]

    • Default: nil

    • Specifies the lower bound of the supported SSL/TLS protocol.

  • max_version: [enum: TLS1_1/TLS1_2/TLS1_3]

    • Default: nil

    • Specifies the upper bound of the supported SSL/TLS protocol.

  • ciphers [string]

    • Default: "ALL:!aNULL:!eNULL:!SSLv2"

    • OpenSSL 1.0.0 or higher default.

  • insecure [bool]

    • Default: false (uses secure connection with tls)

If you want to accept multiple TLS protocols, use min_version/max_version instead of version. To support the old style, fluentd accepts TLS1_1 and TLSv1_1 values.

NOTE: TLS1_3 is available when your system supports TLS 1.3.

Signed Public CA Parameters

For <transport tls>:

  • ca_path: [string]

    • Default: nil

    • Specifies the path of CA certificate file

  • cert_path: [string]

    • Default: nil

    • Specifies the path of Certificate file

  • private_key_path: [string]

    • Default: nil

    • Specifies the path of Private Key file

  • private_key_passphrase: [string]

    • Default: nil

    • Specifies the public CA private key passphrase

  • client_cert_auth: [bool]

    • Default: false

    • If true, Fluentd will check all the incoming HTTPS requests for a

      client certificate signed by the trusted CA. The requests that don't

      supply a valid client certificate will fail.

  • cert_verifier: [string]

    • Default: nil

    • Specifies the code path for cert verification. See also [server

      article](/developer/api-plugin-helper-server.md#cert_verifier-example).

Generated and Signed by Private CA Parameters

For <transport tls>:

  • ca_cert_path: [string]

    • Default: nil

    • Specifies the private CA cert path

  • ca_private_key_path: [string]

    • Default: nil

    • Specifies the private CA private key path

  • ca_private_key_passphrase: [string]

    • Default: nil

    • Specifies the private CA private key passphrase

Generated and Signed by Private CA Certs or Self-signed Parameters

For <transport tls>:

  • generate_private_key_length: [integer]

    • Default: 2048

  • generate_cert_country: [string]

    • Default: US

  • generate_cert_state: [string]

    • Default: CA

  • generate_cert_locality: [string]

    • Default: Mountain View

  • generate_cert_common_name: [string]

    • Default: nil

  • generate_cert_expiration: [integer]

    • Default: (60 * 60 * 24 = 86400) * 365 * 10 = 10 years

Cert Digest Algorithm Parameter

For <transport tls>:

  • generate_cert_digest: [enum: sha1/sha256/sha384/sha512]

    • Default: sha256

If this article is incorrect or outdated, or omits critical information, please let us know. Fluentd is an open-source project under Cloud Native Computing Foundation (CNCF). All components are available under the Apache 2 License.