公式ドキュメントを見ましたが
https://docs.fluentbit.io/manual/installation/raspberry_pi
Raspbian buster 用のリポジトリがなかったのでソースからビルドすることにしました。
準備とソースコードの取得
sudo apt install git build-essential cmake flex bison
git clone https://github.com/fluent/fluent-bit
cd fluent-bit/
git checkout -b work v1.2.2
ビルド
cd build/
cmake ..
make
sudo make install
動作確認
$ fluent-bit -i cpu -o stdout
Fluent Bit v1.2.2
Copyright (C) Treasure Data
[2019/09/07 10:19:27] [ info] [storage] initializing...
[2019/09/07 10:19:27] [ info] [storage] in-memory
[2019/09/07 10:19:27] [ info] [storage] normal synchronization mode, checksum disabled, max_chunks_up=128
[2019/09/07 10:19:27] [ info] [engine] started (pid=16215)
[2019/09/07 10:19:27] [ info] [sp] stream processor started
[0] cpu.0: [1567847968.000457920, {"cpu_p"=>0.000000, "user_p"=>0.000000, "system_p"=>0.000000, "cpu0.p_cpu"=>0.000000, "cpu0.p_user"=>0.000000, "cpu0.p_system"=>0.000000, "cpu1.p_cpu"=>0.000000, "cpu1.p_user"=>0.000000, "cpu1.p_system"=>0.000000, "cpu2.p_cpu"=>0.000000, "cpu2.p_user"=>0.000000, "cpu2.p_system"=>0.000000, "cpu3.p_cpu"=>0.000000, "cpu3.p_user"=>0.000000, "cpu3.p_system"=>0.000000}]
[1] cpu.0: [1567847969.000427993, {"cpu_p"=>0.250000, "user_p"=>0.000000, "system_p"=>0.250000, "cpu0.p_cpu"=>1.000000, "cpu0.p_user"=>0.000000, "cpu0.p_system"=>1.000000, "cpu1.p_cpu"=>0.000000, "cpu1.p_user"=>0.000000, "cpu1.p_system"=>0.000000, "cpu2.p_cpu"=>0.000000, "cpu2.p_user"=>0.000000, "cpu2.p_system"=>0.000000, "cpu3.p_cpu"=>0.000000, "cpu3.p_user"=>0.000000, "cpu3.p_system"=>0.000000}]
[2] cpu.0: [1567847970.000310774, {"cpu_p"=>0.000000, "user_p"=>0.000000, "system_p"=>0.000000, "cpu0.p_cpu"=>0.000000, "cpu0.p_user"=>0.000000, "cpu0.p_system"=>0.000000, "cpu1.p_cpu"=>0.000000, "cpu1.p_user"=>0.000000, "cpu1.p_system"=>0.000000, "cpu2.p_cpu"=>0.000000, "cpu2.p_user"=>0.000000, "cpu2.p_system"=>0.000000, "cpu3.p_cpu"=>0.000000, "cpu3.p_user"=>0.000000, "cpu3.p_system"=>0.000000}]
[3] cpu.0: [1567847971.000277824, {"cpu_p"=>0.000000, "user_p"=>0.000000, "system_p"=>0.000000, "cpu0.p_cpu"=>0.000000, "cpu0.p_user"=>0.000000, "cpu0.p_system"=>0.000000, "cpu1.p_cpu"=>0.000000, "cpu1.p_user"=>0.000000, "cpu1.p_system"=>0.000000, "cpu2.p_cpu"=>0.000000, "cpu2.p_user"=>0.000000, "cpu2.p_system"=>0.000000, "cpu3.p_cpu"=>0.000000, "cpu3.p_user"=>0.000000, "cpu3.p_system"=>0.000000}]
^C[engine] caught signal (SIGINT)