> ## Documentation Index
> Fetch the complete documentation index at: https://dragonwingdocs.qualcomm.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Publish system status with qrb_ros_system_monitor

> The qrb_ros_system_monitor sample application has various ROS nodes that publish system status information, such as CPU loading, memory usage, and disk space.

## Pipeline flow for `qrb_ros_system_monitor`

The following figure shows the pipeline flow, which collects system information with the sysfs node and some system standard command tools and then publishes these data with ROS messages.

<Frame caption="The qrb_ros_system_monitor pipeline.">
  <img src="https://mintcdn.com/qualcomm-prod/eHVY1H1lLEVhgq58/SDKs/QIR-SDK-Ubuntu/images/image6.png?fit=max&auto=format&n=eHVY1H1lLEVhgq58&q=85&s=22e13ecee3243615af3052e9757de494" alt="QRB ROS System Monitor modules reading proc, sysfs, and df sources and publishing the cpu, memory, disk, temperature, battery, and swap topics." width="2645" height="924" data-path="SDKs/QIR-SDK-Ubuntu/images/image6.png" />
</Frame>

## ROS nodes used in the `qrb_ros_system_monitor` pipeline

The following table lists the ROS nodes used in the `qrb_ros_system_monitor` pipeline and describes what each node publishes.

| ROS node             | Description                                              |
| -------------------- | -------------------------------------------------------- |
| `CpuMonitor`         | Publishes CPU loading information.                       |
| `MemoryMonitor`      | Publishes memory usage information.                      |
| `DiskMonitor`        | Publishes disk usage information.                        |
| `SwapMonitor`        | Publishes swap space information                         |
| `TemperatureMonitor` | Publishes CPU temperature.                               |
| `BatteryMonitor`     | Publishes battery information.                           |
| `SystemInfoServer`   | Serves for static system information, such as CPU count. |

## ROS topics used in the `qrb_ros_system_monitor` pipeline

The following table lists the ROS topics used in the `qrb_ros_system_monitor` pipeline, with the message type and a description of each topic.

| ROS topic             | Type                                         | Description                                   |
| --------------------- | -------------------------------------------- | --------------------------------------------- |
| `/cpu`                | `qrb_ros_system_monitor::CpuMonitor`         | CPU loading information.                      |
| `/memory`             | `qrb_ros_system_monitor::MemoryMonitor`      | Memory usage information.                     |
| `/disk`               | `qrb_ros_system_monitor::DiskMonitor`        | Disk usage information.                       |
| `/swap`               | `qrb_ros_system_monitor::SwapMonitor`        | Swap space information                        |
| `/temperature`        | `qrb_ros_system_monitor::TemperatureMonitor` | CPU temperature.                              |
| `/battery`            | `qrb_ros_system_monitor::BatteryMonitor`     | Battery information.                          |
| `/system_info_server` | `qrb_ros_system_monitor::SystemInfoServer`   | Static system information, such as CPU count. |

## ROS services used in the ROS topics used in `qrb_ros_system_monitor` pipeline

The following table lists the ROS services used in the `qrb_ros_system_monitor` pipeline, with the service type and a description.

| ROS service           | Type                                       | Description                                   |
| --------------------- | ------------------------------------------ | --------------------------------------------- |
| `/system_info_server` | `qrb_ros_system_monitor::SystemInfoServer` | Static system information, such as CPU count. |

## Prerequisites

You have set up the device, installed ROS2 Jazzy and the Qualcomm Intelligent Robotics (QIR) SDK on the device according to [Install the QIR SDK](./install-the-qir-sdk).

## Run out-of-the-box `qrb_ros_system_monitor`

<Steps>
  <Step title="In terminal 1, run qrb_ros_system_monitor">
    ```bash Run the system monitor theme={null}
    source /opt/ros/jazzy/setup.bash
    ros2 run qrb_ros_system_monitor qrb_ros_system_monitor
    ```
  </Step>

  <Step title="In terminal 2, get the topics of this node and check system status as needed">
    ```bash List the topics and echo the system status theme={null}
    source /opt/ros/jazzy/setup.bash
    ros2 topic list
    # You can now echo system monitor, for example, /cpu
    ros2 topic echo /cpu
    ```
  </Step>
</Steps>

## Limitation

The system information values are collected by the sysfs node and Linux standard command-line tools. Therefore, if the sysfs path changes or the command-line tools output format changes, those ROS nodes may not work properly.