---
title: "Configure static mode | Grafana Agent documentation"
description: "Learn how to configure Grafana Agent in static mode"
---

# Configure static mode

The configuration of static mode is split across two places:

- A YAML file
- [Command-line flags](/docs/agent/v0.43/static/configuration/flags/)

The YAML file is used to configure settings which are dynamic and can be changed at runtime. The command-line flags then configure things which cannot change at runtime, such as the listen port for the HTTP server.

This file describes the YAML configuration, which is usually in a file named `config.yaml`.

- [server\_config](/docs/agent/v0.43/static/configuration/server-config/)
- [metrics\_config](/docs/agent/v0.43/static/configuration/metrics-config/)
- [logs\_config](/docs/agent/v0.43/static/configuration/logs-config/)
- [traces\_config](/docs/agent/v0.43/static/configuration/traces-config/)
- [integrations\_config](/docs/agent/v0.43/static/configuration/integrations/)

The configuration of Grafana Agent is “stable,” but subject to breaking changes as individual features change. Breaking changes to configuration will be well-documented.

## Updating configuration

The configuration file can be reloaded at runtime using the `/-/reload` API endpoint or sending a SIGHUP signal to the process.

## Variable substitution

You can use environment variables in the configuration file to set values that need to be configurable during deployment. To enable this functionality, you must pass `-config.expand-env` as a command-line flag to the Agent.

To refer to an environment variable in the config file, use:

![Copy code to clipboard](/media/images/icons/icon-copy-small-2.svg) Copy

```none
${VAR}
```

Where VAR is the name of the environment variable.

Each variable reference is replaced at startup by the value of the environment variable. The replacement is case-sensitive and occurs before the YAML file is parsed. References to undefined variables are replaced by empty strings unless you specify a default value or custom error text.

To specify a default value, use:

![Copy code to clipboard](/media/images/icons/icon-copy-small-2.svg) Copy

```none
${VAR:-default_value}
```

Where default\_value is the value to use if the environment variable is undefined. The full list of supported syntax can be found at Drone’s [envsubst repository](https://github.com/drone/envsubst).

### Regex capture group references

When using `-config.expand-env`, `VAR` must be an alphanumeric string with at least one non-digit character. If `VAR` is a number, the expander will assume you’re trying to use a regex capture group reference, and will coerce the result to be one.

This means references in your config file like `${1}` will remain untouched, but edge cases like `${1:-default}` will also be coerced to `${1}`, which may be slightly unexpected.

## Reloading (beta)

The configuration file can be reloaded at runtime. Read the [API documentation](/docs/agent/v0.43/static/api/#reload-configuration-file-beta) for more information.

This functionality is in beta, and may have issues. Please open GitHub issues for any problems you encounter.

## File format

To specify which configuration file to load, pass the `-config.file` flag at the command line. The file is written in the [YAML format](https://en.wikipedia.org/wiki/YAML), defined by the scheme below. Brackets indicate that a parameter is optional. For non-list parameters the value is set to the specified default.

Generic placeholders are defined as follows:

- `<boolean>`: a boolean that can take the values `true` or `false`
- `<int>`: any integer matching the regular expression `[1-9]+[0-9]*`
- `<duration>`: a duration matching the regular expression `[0-9]+(ns|us|µs|ms|[smh])`
- `<labelname>`: a string matching the regular expression `[a-zA-Z_][a-zA-Z0-9_]*`
- `<labelvalue>`: a string of unicode characters
- `<filename>`: a valid path relative to current working directory or an absolute path.
- `<host>`: a valid string consisting of a hostname or IP followed by an optional port number
- `<string>`: a regular string
- `<secret>`: a regular string that is a secret, such as a password

Support contents and default values of `config.yaml`:

YAML ![Copy code to clipboard](/media/images/icons/icon-copy-small-2.svg) Copy

```yaml
# Configures the server of the Agent used to enable self-scraping.
[server: <server_config>]

# Configures metric collection.
# In previous versions of the agent, this field was called "prometheus".
[metrics: <metrics_config>]

# Configures log collection.
# In previous versions of the agent, this field was called "loki".
[logs: <logs_config>]

# Configures Traces trace collection.
# In previous versions of the agent, this field was called "tempo".
[traces: <traces_config>]

# Configures integrations for the Agent.
[integrations: <integrations_config>]
```

## Remote Configuration (Experimental)

An experimental feature for fetching remote configuration files over HTTP/S can be enabled by passing the `-enable-features=remote-configs` flag at the command line. With this feature enabled, you may pass an HTTP/S URL to the `-config.file` flag.

The following flags will configure basic auth for requests made to HTTP/S remote config URLs:

- `-config.url.basic-auth-user <user>`: the basic auth username
- `-config.url.basic-auth-password-file <file>`: path to a file containing the basic auth password

> Note
> 
> This beta feature is subject to change in future releases.