# Fluentd Reference

td-agent was discontinued in December 2023 and has been replaced by **fluent-package**. The fluent-package is the official successor maintained by the [Cloud Native Computing Foundation](https://www.cncf.io/projects/).

The following files are installed by the rpm or Debian packages.

## fluent-package 6.x

| Resource | Location | Notes |
|  --- | --- | --- |
| Config Directory | /etc/fluent/ |  |
| Config File | /etc/fluent/fluentd.conf | This config will be picked-up by the startup script |
| Startup Script | /usr/lib/systemd/system/fluentd.service |  |
| Log Directory | /var/log/fluent/ |  |
| Plugin Directory | /etc/fluent/plugin/ | Your custom plugins go here. |
| Ruby Interpreter | /opt/fluent/bin/ruby | Ruby is bundled with the package. |
| Rubygems | /opt/fluent/bin/fluent-gem | Bundled rubygems to install fluentd plugins. For example: `fluent-gem install fluent-plugin-mongo` |
| jemalloc | /opt/fluent/lib/libjemalloc.so | [jemalloc](http://jemalloc.net/) is bundled together to avoid memory fragmentation. It is loaded by default in the startup script. |


## Supervision, Privileges and Network Ports

When Fluentd starts, it launches 2 processes: parent and child. The parent process is managing the life cycle of the child process, and the child process handles actual log collection.


```bash
$ ps w -C ruby -C fluentd --no-heading
```


```bash
26238 ? Sl 0:00 /opt/fluent/bin/ruby /opt/fluent/bin/fluentd --config /etc/fluent/fluentd.conf --log /var/log/fluent/fluentd.log
26243 ? Sl 0:25 /opt/fluent/bin/ruby /opt/fluent/bin/fluentd --config /etc/fluent/fluentd.conf --log /var/log/fluent/fluentd.log --under-supervisor
```

Both processes run as the `fluentd` user under `fluentd` group and all forked subprocesses run as the same. This applies to any system call initiated by Fluentd as well. The agent configuration resides at `/etc/fluent/fluentd.conf`. All configurations must be readable by the fluentd user.

The following ports are open depending on your input.

* in_tail: nothing
* in_forward: tcp/24224, udp/24224
* in_unix: `/var/run/fluent/fluentd.sock`


For secure uploading to Treasure Data, you must open tcp/443 (https) for `*.treasuredata.com`.

## Other Resources

- [Fluentd Documentation](https://docs.fluentd.org/)