Hot Reload

Fluent Bit supports the hot reloading feature when enabled via the configuration file or command line with -Y or --enable-hot-reload option.

Getting Started

To get started with reloading via HTTP, the first step is to enable the HTTP Server from the configuration file:

[SERVICE]
    HTTP_Server  On
    HTTP_Listen  0.0.0.0
    HTTP_PORT    2020
    Hot_Reload   On
...

The above configuration snippet will enable the HTTP endpoint for hot reloading.

How to reload

Via HTTP

Hot reloading can be kicked via HTTP endpoints that are:

• PUT /api/v2/reload

• POST /api/v2/reload

If users don't enable the hot reloading feature, hot reloading via these endpoints will not work.

For using curl to reload Fluent Bit, users must specify an empty request body as:

$ curl -X POST -d '{}' localhost:2020/api/v2/reload

Via Signal

Hot reloading also can be kicked via SIGHUP.

SIGHUP signal is not supported on Windows. So, users can't enable this feature on Windows.

How to confirm reloaded or not

via HTTP

The number of hot reloaded count can be obtained via the HTTP endpoint that is:

• GET /api/v2/reload

The endpoint returns the count of hot-reloaded as follows:

{"hot_reload_count":3}

The default value of that number is 0.

Limitations

The hot reloading feature is currently working on Linux, macOS and Windows.