Docker Images

Fluent Bit container images are available on Docker Hub ready for production usage. Our stable images are based in Distroless focusing on security containing just the Fluent Bit binary, minimal system libraries and basic configuration.

Optionally, we provide debug images which contains Busybox that can be used to troubleshoot or testing purposes.

The following table describe the tags are available on fluent/fluent-bit repository:

Tag(s)	Description
1.2, 1.2-debug	Latest release of 1.2.x series
1.2.0, 1.2.0-debug	Container image of Fluent Bit v1.2.0

It's strongly suggested that you always use the latest image of Fluent Bit.

Getting Started

Download the last stable image from 1.0 series:

$ docker pull fluent/fluent-bit:1.2

Once the image is in place, now run the following (useless) test which makes Fluent Bit meassure CPU usage by the container:

$ docker run -ti fluent/fluent-bit:1.2 /fluent-bit/bin/fluent-bit -i cpu -o stdout -f 1

That command will let Fluent Bit measure CPU usage every second and flush the results to the standard output, e.g:

Fluent-Bit v1.2.x
Copyright (C) Treasure Data

[2017/11/07 14:29:02] [ info] [engine] started
[0] cpu.0: [1504290543.000487750, {"cpu_p"=>0.750000, "user_p"=>0.250000, "system_p"=>0.500000, "cpu0.p_cpu"=>0.000000, "cpu0.p_user"=>0.000000, "cpu0.p_system"=>0.000000, "cpu1.p_cpu"=>1.000000, "cpu1.p_user"=>0.000000, "cpu1.p_system"=>1.000000, "cpu2.p_cpu"=>1.000000, "cpu2.p_user"=>1.000000, "cpu2.p_system"=>0.000000, "cpu3.p_cpu"=>0.000000, "cpu3.p_user"=>0.000000, "cpu3.p_system"=>0.000000}]

F.A.Q

Why there is no Fluent Bit Docker image based on Alpine Linux ?

Alpine Linux uses Musl C library instead of Glibc. Musl is not fully compatible with Glibc which generated many issues in the following areas when used with Fluent Bit:

• Memory Allocator: to run Fluent Bit properly in high-load environments, we use Jemalloc as a default memory allocator which reduce fragmentation and provides better performance for our needs. Jemalloc cannot run smoothly with Musl and requires extra work.

• Alpine Linux Musl functions bootstrap have a compatibility issue when loading Golang shared libraries, this generate problems when trying to load Golang output plugins in Fluent Bit.

• Alpine Linux Musl Time format parser does not support Glibc extensions

• Maintainers preference in terms of base image due to security and maintenance reasons are Distroless and Debian.