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Transport Security

Fluent Bit provides integrated support for Transport Layer Security (TLS) and it predecessor Secure Sockets Layer (SSL) respectively. In this section we will refer as TLS only for both implementations.
Both input and output plugins that perform Network I/O can optionally enable TLS and configure the behavior. The following table describes the properties available:
Property
Description
Default
tls
enable or disable TLS support
Off
tls.verify
force certificate validation
On
tls.debug
Set TLS debug verbosity level. It accept the following values: 0 (No debug), 1 (Error), 2 (State change), 3 (Informational) and 4 Verbose
1
tls.ca_file
absolute path to CA certificate file
tls.ca_path
absolute path to scan for certificate files
tls.crt_file
absolute path to Certificate file
tls.key_file
absolute path to private Key file
tls.key_passwd
optional password for tls.key_file file
tls.vhost
hostname to be used for TLS SNI extension
Note : in order to use TLS on input plugins the user is expected to provide both a certificate and private key
The listed properties can be enabled in the configuration file, specifically on each output plugin section or directly through the command line.
The following output plugins can take advantage of the TLS feature:
The following input plugins can take advantage of the TLS feature:
In addition, other plugins implements a sub-set of TLS support, meaning, with restricted configuration:

Example: enable TLS on HTTP input

By default HTTP input plugin uses plain TCP, enabling TLS from the command line can be done with:
./bin/fluent-bit -i http \
-p port=9999 \
-p tls=on \
-p tls.verify=off \
-p tls.crt_file=self_signed.crt \
-p tls.key_file=self_signed.key \
-o stdout \
-m '*'
In the command line above, the two properties tls and tls.verify where enabled for demonstration purposes (we strongly suggest always keep verification ON).
The same behavior can be accomplished using a configuration file:
[INPUT]
name http
port 9999
tls on
tls.verify off
tls.crt_file self_signed.crt
tls.key_file self_signed.key
[OUTPUT]
Name stdout
Match *

Example: enable TLS on HTTP output

By default HTTP output plugin uses plain TCP, enabling TLS from the command line can be done with:
$ fluent-bit -i cpu -t cpu -o http://192.168.2.3:80/something \
-p tls=on \
-p tls.verify=off \
-m '*'
In the command line above, the two properties tls and tls.verify where enabled for demonstration purposes (we strongly suggest always keep verification ON).
The same behavior can be accomplished using a configuration file:
[INPUT]
Name cpu
Tag cpu
[OUTPUT]
Name http
Match *
Host 192.168.2.3
Port 80
URI /something
tls On
tls.verify Off

Tips and Tricks

Generate your own self signed certificates for testing purposes.

This will generate a 4096 bit RSA key pair and a certificate that is signed using SHA-256 with the expiration date set to 30 days in the future, test.host.net set as common name and since we opted out of DES the private key will be stored in plain text.
openssl req -x509 \
-newkey rsa:4096 \
-sha256 \
-nodes \
-keyout self_signed.key \
-out self_signed.crt \
-subj "/CN=test.host.net"

Connect to virtual servers using TLS

Fluent Bit supports TLS server name indication. If you are serving multiple hostnames on a single IP address (a.k.a. virtual hosting), you can make use of tls.vhost to connect to a specific hostname.
[INPUT]
Name cpu
Tag cpu
[OUTPUT]
Name forward
Match *
Host 192.168.10.100
Port 24224
tls On
tls.verify On
tls.ca_file /etc/certs/fluent.crt
tls.vhost fluent.example.com
Last modified 3mo ago