Lab 1 - Introduction to Fluent Bit

Lab Goal

To gain an understanding of Fluent Bit and its role in cloud native observability.

Introduction - Defining pipelines

Before we get started, let's get on the same page with a definition of cloud native observability pipelines. As noted in a recent trend report:
Observability pipelines are providing real-time filtering, enrichment, normalization and routing of telemetry data

Introduction - Pipeline trends

The rise in the amount of data being generated in cloud native environments has become such a burden for teams trying to manage it all, as well as a burden to organization's budgets. As they are searching for more control over all this telemetry data, from collecting, processing, and routing, to storing and querying.

Data pipelines have gained significant traction in helping organizations deal with the challenges they are facing by providing a powerful way to lower ingestion volumes and help reduce data costs.

Introduction - Telemetry pipeline benefits

Telemetry pipelines act as a telemetry gateway between cloud native data and organizations. It's performing real-time filtering, enrichment, normalization, and routing to cheap storage. This reduces dependencies on expensive and often proprietary storage solutions.

Another plus for organizations is the ability to reformat collected data on the fly, often bridging the gap between legacy or non-standards based data structures to current standards. They can achieve this without having to update code, re-instrument, or redeploy existing applications and services.

Introduction - What is Fluent Bit?

From the project documentation, Fluent Bit is an open source telemetry agent specifically designed to efficiently handle the challenges of collecting and processing telemetry data across a wide range of environments, from constrained systems to complex cloud infrastructures. It's effective at managing telemetry data from various sources and formats can be a constant challenge, particularly when performance is a critical factor.

Introduction - Telemetry pipeline background

Before we get started, let's get on the same page with what cloud native telemetry pipelines are. As noted in a recent report, "Telemetry pipelines providing real-time filtering, enrichment, normalization and routing of telemetry data".

Introduction - What does Fluent Bit do?

Rather than serving as a drop-in replacement, Fluent Bit enhances the observability strategy for your infrastructure by adapting and optimizing your existing logging layer, as well as metrics and traces processing. Furthermore, Fluent Bit supports a vendor-neutral approach, seamlessly integrating with other ecosystems such as Prometheus and OpenTelemetry.

Fluent Bit can be deployed as an edge agent for localized telemetry data handling or utilized as a central aggregator or collector for managing telemetry data across multiple sources and environments. Fluent Bit has been designed for performance and low resource consumption.

Introduction - Fluent Bit data pipeline

Designed to process logs, metrics, and traces at speed, scale, and with flexibility:

Introduction - What about Fluentd?

First there was Fluentd, a CNCF Graduated Project. It's an open source data collector for building the unified logging layer . When installed, it runs in the background to collect, parse, transform, analyze and store various types of data.

Fluent Bit is a sub-project within the Fluentd ecosystem. It's considered a Lightweight Data Forwarder for Fluentd. Fluent Bit is specifically designed for forwarding the data from the edge to Fluentd aggregators.

Introduction - Fluentd to Fluent Bit comparison

Both projects share similarities, Fluent Bit is fully designed and built on top of the best ideas of Fluentd architecture and general design:

Introduction - Understanding Fluent Bit concepts

Before we dive into using Fluent Bit, it's important to have an understanding of the key concepts, so let's explore the following:

  • Event or Record
  • Filtering
  • Tag
  • Timestamp
  • Match
  • Structured Message

Introduction - What is an Event or Record?

Each incoming piece of data is considered an Event or a Record. This lab uses Event as the preferred terminology. An example of an Event is shown below in a sample log file, with each line representing one Event:
								Feb 26 09:49:58 EricsM2 syslogd[361]: ASL Sender Statistics
								Feb 26 09:51:18 EricsM2 AMPDeviceDiscoveryAgent[764]: mux-device:1392
								Feb 26 09:53:18 EricsM2 AMPDeviceDiscoveryAgent[764]: Entered:__thr_AMMuxedDeviceDisconnected
								Feb 26 00:30:30 EricsM2 syslogd[361]: ASL Module ""
Events have a strict format of timestamp, key/value metadata, and payload.

Introduction - Fluent Bit wire protocol and Events

Fluent Bit communicates with its own wire protocol that represents each Event as a two element array with a nested first element:
  • TIMESTAMP - in seconds as integer or floating point value (!STRING)
  • METADATA - is a possibly-empty object containing event metadata
  • MESSAGE - is an object containing the event body

Intermezzo - Older Fluent Bit wire protocol

Previous versions of Fluent Bit (prior to v2.1.0) represent each Event in a different format, without the metadata element:
Note that this older format is supported for reading input event streams.

Introduction - Filtering on our events

The concept of Filtering is when we need to perform modifications on the contents of an Event, the process of altering, enriching, or dropping an Event. A few examples of this are:
  • Appending specific information to an Event, such as an IP address
  • Select a specific piece of the Event content
  • Drop Events that matches certain criteria

Introduction - Everything gets a Tag

Every singe Event, every one, is given a Tag as it enters our Fluent Bit pipeline. The Tag is an internal string used by the Router in later stages of our pipeline to determine which filters or output phases an Event must pass through.

A tagged Event must always have a matching rule, see the official Router documentation for details.
Note: One input plugin does NOT assign tags, the Forward input. It uses the Fluentd wire protocol called Forward where every Event comes with a Tag. Fluent Bit always uses the incoming Tag set by a client.

Introduction - What is a Timestamp?

A Timestamp is assigned to each Event as it enters a pipeline, is always present, and is a numerical fraction in the form of:
  • SECONDS - number of seconds that have elapsed since the Unix epoch.
  • NANOSECONDS - fractional second or one thousand-millionth of a second.

Introduction - Matching our Events

Fluent Bit delivers collected and processed Events to possible destinations by using a routing phase. A Match represent a rule applied to Events where it examines its Tags for matches.

For more details around Matches and Tags, see the Router documentation.

Introduction - Unstructured or Structured Messages

When Events enter the system they can be viewed as either unstructured or structured Event Messages. The goal of Fluent Bit is to ensure that all message have a structured format, defined as having keys and values, which ensures faster operations on data modifications.

Unstructured message:
								"This workshop was created on 1456289299"
Structured message:
								{"project": "workshop", "created": 1456289299}

Intermezzo - It's always a structured message

Fluent Bit treats every single Event message as a structured message. It uses internally a binary serialization data format called MessagePack, which is like a version of JSON on steroids.

Introduction - Buffering basics for pipelines

A major issue with data pipelines is finding a way to store data that is ingested. We need in-memory storage to hold the data you are processing (fast), but we also don't want to lose data when this first storage is full. To achieve that we need a secondary storage to hold all data that does not fit into memory.

All of this is known as data buffering, having the ability to store Events somewhere, while processing and delivering them, to still be able to store more.

Introduction - Fluent Bit's buffering strategy

Networks fail all the time, or have latency issues causing delays in data delivery. There are many scenarios where we can not deliver data fast enough as we are receiving it in our pipeline. When this happens it's a phenomenon known as backpressure, and Fluent Bit is designed with buffering strategies to solve these issues.

Fluent Bit offers a primary buffering mechanism in memory and an optional secondary buffering mechanism using the file system. This hybrid solution provides for high performance while processing incoming data and ensures no data loss due to the issues described above. Data ready for processing will always be in-memory, while other data might be in the filesystem until ready to be processes.

Introduction - Telemetry pipeline input phase

A telemetry pipeline is where data goes through various phases from collection to final destination. We can define or configure each phase to manipulate the data or the path it's taking through our telemetry pipeline. The first phase is INPUT, which is where Fluent Bit uses Input Plugins to gather information from specific sources. When an input plugin is loaded it creates an instance which we can configure using the plugins properties.

Introduction - Data pipeline parser phase

The second phase is PARSER, which is where unstructured input data is turned into structured data. Fluent Bit does this using Parsers that we can configure to manipulate the unstructured data producing structured data for the next phases of our pipeline.

Introduction - Example data pipeline parsing

Here's an example of unstructured log data entering the Parser phase:
						 - - [28/Jul/2006:10:27:10 -0300] "GET /cgi-bin/try/ HTTP/1.0" 200 3395
And the parsing results with structured data as the output:
								  "host":    "",
								  "user":    "-",
								  "method":  "GET",
								  "path":    "/cgi-bin/try/",
								  "code":    "200",
								  "size":    "3395"

Introduction - Data pipeline filter phase

Filtering phase is when we modify, enrich, or delete any of the collected Events. Fluent Bit provides many out of the box plugins as Filters that can match, exclude, or enrich your structured data before it moves onwards in the pipeline. Filters can be configured using the provided properties.

Introduction - Data pipeline buffer phase

Buffering was discussed previously, but here in the pipeline is where the data is stored, using in-memory or the file system based options. Note that when data reaches the buffer phase it's in an immutable state (no more filtering) and that buffered data is not raw text, but in an internal binary representation for storage.

Introduction - Data pipeline routing phase

The next phase is ROUTING, which is where Fluent Bit uses the previously discussed Tag and Match concepts to determine which output destinations to send data. During the INPUT phase data is assigned a Tag, during the ROUTING phase data is compared to Match rules from output configurations, if it matches then the data is sent to that output destination.

Introduction - Example routing to database and memory

In this example we'll collect and Tag two metrics, cpu and memory, which we then want to go to separate output destinations. This is configured as follows, noting all matching happens on Tag values:
									Name cpu
									Tag  my_cpu

									Name mem
									Tag  my_mem

									Name   database
									Match  my_cpu

									Name   stdout
									Match  my_mem

Introduction - Example routing using wildcards

In this example we'll collect and Tag the same two metrics, cpu and memory, which we then send to the console output using a catch-all wildcard:
									Name cpu
									Tag  my_cpu

									Name mem
									Tag  my_mem

									Name   stdout
									Match  my_*

Introduction - Example routing with regular expressions

In this example we'll collect and Tag two sensor metrics which we then send to the console output using a the Match_regex pattern that matches all tags ending with "_sensor_A" or "_sensor_B":
									Name temperature_sensor
									Tag  temp_sensor_A

									Name humidity_sensor
									Tag  humid_sensor_B

									Name         stdout
									Match_regex  .*_sensor_[AB]

Introduction - Data pipeline output phase

The final phase is OUTPUT, which is where Fluent Bit uses Output Plugins to connect with specific destinations. These destinations can be databases, remote services, cloud services, and more. When an input plugin is loaded it creates an instance which we can configure using the plugins properties.

Lab completed - Results

We gained a basic understanding of Fluent Bit.
Next up, installing Fluent Bit on your machine.

Contact - are there any questions?

Eric D. Schabell
Director Evangelism
Contact: @ericschabell { or

Up next in workshop...

Lab 2 - Installing Fluent Bit