> ## Documentation Index
> Fetch the complete documentation index at: https://dragonwingdocs-staging.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-staging/blZpKs_b9On5nj-y/archives/2.1/SDKs/QIR-SDK-Ubuntu/images/image6.png?fit=max&auto=format&n=blZpKs_b9On5nj-y&q=85&s=2b01233923984b0430e6d6b23dc2faa4" 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="archives/2.1/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.