Internal Architecture

3. Internal architecture #

Components, services, and the Directed Acyclic Graph (DAG).

The DAG at the core of the system #

Alloy's internal architecture is based on a Directed Acyclic Graph (DAG). Each configuration block (e.g., discovery, scraping, forwarding) is a component (a node in the graph). Alloy automatically determines the execution order and dependencies between these components. If the configuration changes, only the affected components are reloaded, without restarting the whole process.

Best Practice: Favor splitting your configurations into multiple small River files rather than one huge file. Alloy can load an entire directory, which facilitates organization by team or domain.

Common Mistake: Manually restarting the service (systemctl restart alloy) for every configuration change. Use the hot-reload API instead to apply changes without service interruption.

# Loading an entire directory (more modular)
alloy run /etc/alloy/config.d/

# Hot-reloading the configuration
curl -X POST http://localhost:12345/-/reload