ワンライナーでいける
https://docs.fluentbit.io/manual/installation/linux/ubuntu
環境変数使えるかの検証。タグには使えるけどファイルのIncludeには使えなかった
/lib/systemd/system/fluent-bit.serviceに設定
[Service] Type=simple Environment=TAG_NAME=env_tag_value Environment=INCLUDE_TYPE=file EnvironmentFile=-/etc/sysconfig/fluent-bit EnvironmentFile=-/etc/default/fluent-bit ExecStart=/opt/fluent-bit/bin/fluent-bit -c //etc/fluent-bit/fluent-bit.conf Restart=always [Install] WantedBy=multi-user.target