Fluent Bit is distributed as td-agent-bit package and is available for the latest stable Ubuntu system: Focal Fossa.

Server GPG key

The first step is to add our server GPG key to your keyring, on that way you can get our signed packages:
$ wget -qO - https://packages.fluentbit.io/fluentbit.key | sudo apt-key add -

Update your sources lists

On Ubuntu, you need to add our APT server entry to your sources lists, please add the following content at bottom of your /etc/apt/sources.list file:

Ubuntu 20.04 LTS (Focal Fossa)

deb https://packages.fluentbit.io/ubuntu/focal focal main

Ubuntu 18.04 LTS (Bionic Beaver)

deb https://packages.fluentbit.io/ubuntu/bionic bionic main

Ubuntu 16.04 LTS (Xenial Xerus)

deb https://packages.fluentbit.io/ubuntu/xenial xenial main

Update your repositories database

Now let your system update the apt database:
$ sudo apt-get update

Install TD-Agent Bit

Using the following apt-get command you are able now to install the latest td-agent-bit:
$ sudo apt-get install td-agent-bit
Now the following step is to instruct systemd to enable the service:
$ sudo service td-agent-bit start
If you do a status check, you should see a similar output like this:
sudo service td-agent-bit status
● td-agent-bit.service - TD Agent Bit
Loaded: loaded (/lib/systemd/system/td-agent-bit.service; disabled; vendor preset: enabled)
Active: active (running) since mié 2016-07-06 16:58:25 CST; 2h 45min ago
Main PID: 6739 (td-agent-bit)
Tasks: 1
Memory: 656.0K
CPU: 1.393s
CGroup: /system.slice/td-agent-bit.service
└─6739 /opt/td-agent-bit/bin/td-agent-bit -c /etc/td-agent-bit/td-agent-bit.conf
The default configuration of td-agent-bit is collecting metrics of CPU usage and sending the records to the standard output, you can see the outgoing data in your /var/log/syslog file.