# System launch files

## Overview

The Autoware system stack starts with `autoware.launch.xml`, as the [Launch Autoware](<../index.md>) page explains. If `launch_system` is `true`, `autoware.launch.xml` includes `tier4_system_component.launch.xml` of the `autoware_launch` package. This file includes `system.launch.xml` of the [`tier4_system_launch`](<https://github.com/autowarefoundation/autoware_launch/tree/0.53.0/tier4_universe_launch/tier4_system_launch>) package. The following diagram shows the system launch flow in the `autoware_launch` repository.

tier4\_system\_component.launch.xml includes system.launch.xml, which launches the system packages that its launch arguments enable.

> [!NOTE]
>
> The Autoware project is a large project. Therefore, as we manage the Autoware project, we utilize specific arguments in the launch files. ROS 2 offers an argument-overriding feature for these launch files. Please refer to [the official ROS 2 launch documentation](<https://docs.ros.org/en/humble/Tutorials/Intermediate/Launch/Using-ROS2-Launch-For-Large-Projects.html#parameter-overrides>) for further information. For instance, if we define an argument at the top-level launch, it will override the value on lower-level launches.

As the flow diagram shows, `system.launch.xml` of `tier4_system_launch` always launches these packages:

- [duplicated\_node\_checker](<https://autowarefoundation.github.io/autoware_universe/main/system/autoware_duplicated_node_checker/>)
- [processing\_time\_checker](<https://autowarefoundation.github.io/autoware_universe/main/system/autoware_processing_time_checker/>)
- [pipeline\_latency\_monitor](<https://autowarefoundation.github.io/autoware_universe/main/system/autoware_pipeline_latency_monitor/>)
- [component\_state\_monitor](<https://autowarefoundation.github.io/autoware_universe/main/system/autoware_component_state_monitor/>)
- [mrm\_emergency\_stop\_operator](<https://autowarefoundation.github.io/autoware_universe/main/system/autoware_mrm_emergency_stop_operator/>)
- [diagnostic\_graph\_aggregator](<https://autowarefoundation.github.io/autoware_universe/main/system/autoware_diagnostic_graph_aggregator/>)
- [hazard\_status\_converter](<https://github.com/autowarefoundation/autoware_universe/tree/0.53.1/system/autoware_hazard_status_converter>)

It launches these packages when their launch arguments allow it:

- [system\_monitor](<https://autowarefoundation.github.io/autoware_universe/main/system/autoware_system_monitor/>), if `launch_system_monitor` is `true` (the default).
- [mrm\_comfortable\_stop\_operator](<https://autowarefoundation.github.io/autoware_universe/main/system/autoware_mrm_comfortable_stop_operator/>) and [mrm\_handler](<https://autowarefoundation.github.io/autoware_universe/main/system/autoware_mrm_handler/>), if `use_control_command_gate` is `false` (the default).
- [command\_mode\_switcher](<https://autowarefoundation.github.io/autoware_universe/main/system/autoware_command_mode_switcher/>) and [command\_mode\_decider](<https://autowarefoundation.github.io/autoware_universe/main/system/autoware_command_mode_decider/>), if `use_control_command_gate` is `true`.
- [dummy\_diag\_publisher](<https://autowarefoundation.github.io/autoware_universe/main/simulator/autoware_dummy_diag_publisher/>), if `launch_dummy_diag_publisher` is `true`. The default is `false`.

`tier4_system_component.launch.xml` also includes `logging.launch.xml` of [diagnostic\_graph\_utils](<https://autowarefoundation.github.io/autoware_universe/main/system/autoware_diagnostic_graph_utils/>). It logs the errors of the diagnostic graph in the terminal.

`autoware.launch.xml` has these system arguments:

| Argument | Default value | Description |
| --- | --- | --- |
| `system_run_mode` | `online` | The run mode of the system. The options are `online`, `logging_simulation`, `planning_simulation`. |
| `launch_system_monitor` | `true` | Launch the system monitor. |
| `launch_dummy_diag_publisher` | `false` | Launch the dummy diagnostic publisher. |
| `diagnostic_graph_aggregator_graph_path` | `$(find-pkg-share autoware_launch)/config/system/diagnostics/autoware-main.yaml` | The graph file of the diagnostic graph aggregator. |

For example, to use your own diagnostic graph, launch Autoware with this command-line argument:

```bash
ros2 launch autoware_launch autoware.launch.xml ... diagnostic_graph_aggregator_graph_path:=<YOUR-DIAGNOSTIC-GRAPH-PATH> ...
```

The parameter files of the system packages are in the `config/system/` directory of the `autoware_launch` package. `tier4_system_component.launch.xml` gives their paths to `system.launch.xml` as fixed values, so a command-line argument cannot change them. To use another parameter file, change the path in your `tier4_system_component.launch.xml`. For example, for the parameter file of `mrm_handler`:

```diff
- <arg name="mrm_handler_param_path" value="$(find-pkg-share autoware_launch)/config/system/mrm_handler/mrm_handler.param.yaml"/>
+ <arg name="mrm_handler_param_path" value="<YOUR-MRM-HANDLER-PARAM-PATH>"/>
```