# Build with static configuration

[Fluent Bit](https://fluentbit.io) in normal operation mode is configurable through text files or using specific arguments in the command line. Although this is the ideal deployment case, there are scenarios where a more restricted configuration is required. Static configuration mode restricts configuration ability.

Static configuration mode includes a built-in configuration in the final binary of Fluent Bit, disabling the usage of external files or flags at runtime.

## Get started

### Requirements

The following steps assume you are familiar with configuring Fluent Bit using text files and you have experience building it from scratch as described in [Build and Install](https://docs.fluentbit.io/manual/installation/downloads/source/build-and-install).

#### Configuration directory

In your file system, prepare a specific directory that will be used as an entry point for the build system to lookup and parse the configuration files. This directory must contain a minimum of one configuration file, called `fluent-bit.conf`, that contains the required [`SERVICE`](https://docs.fluentbit.io/manual/administration/configuring-fluent-bit/yaml/service-section), [`INPUT`](https://docs.fluentbit.io/manual/data-pipeline/inputs), and [`OUTPUT`](https://docs.fluentbit.io/manual/data-pipeline/outputs) sections.

As an example, create a new `fluent-bit.yaml` file or `fluent-bit.conf` file:

{% tabs %}
{% tab title="fluent-bit.yaml" %}

```yaml
service:
  flush: 1
  daemon: off
  log_level: info

pipeline:
  inputs:
    - name: cpu

  outputs:
    - name: stdout
      match: '*'
```

{% endtab %}

{% tab title="fluent-bit.conf" %}

```
[SERVICE]
  Flush     1
  Daemon    off
  Log_Level info

[INPUT]
  Name      cpu

[OUTPUT]
  Name      stdout
  Match     *
```

{% endtab %}
{% endtabs %}

This configuration calculates CPU metrics from the running system and prints them to the standard output interface.

#### Build with custom configuration

1. Go to the Fluent Bit source code build directory:

   ```shell
   cd fluent-bit/build/
   ```
2. Run CMake, appending the `FLB_STATIC_CONF` option pointing to the configuration directory recently created:

   ```shell
   cmake -DFLB_STATIC_CONF=/path/to/my/confdir/
   ```
3. Build Fluent Bit:

   ```shell
   make
   ```

The generated `fluent-bit` binary is ready to run without additional configuration:

```shell
$ bin/fluent-bit

...
[0] cpu.local: [1539984752.000347547, {"cpu_p"=>0.750000, "user_p"=>0.500000, "system_p"=>0.250000, "cpu0.p_cpu"=>1.000000, "cpu0.p_user"=>1.000000, "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"=>1.000000, "cpu3.p_user"=>1.000000, "cpu3.p_system"=>0.000000}]
```