sysinfo_MQTTtoHA

Introduction

The shell script sysmonitor_MQTTtoHA.sh collects some system information on the Linux machine it is executed on and publishes MQTT messages using JSON format with some system information:

• Hostname
• IP address (with connection type Ethernet or Wireless and SSID)
• Uptime
• CPU load
• Temperature
• Disk size and usage (%)
• Memory ans Swap usages
• Type of proecessors
• Number of processors
• Model (for Raspberry Pi, Odroid...)
• Operating system

Below is an example of JSON message:

{
  "hostname": "Corei5-lab",
  "os": "Ubuntu 20.04.3 LTS",
  "proc": "Intel(R) Core(TM) i5-10500 CPU @ 3.10GHz",
  "nproc": "12",
  "cpu_load": "1.1",
  "disk_size": "457G",
  "disk_usage": "11",
  "memory": "13.2",
  "swap": "0.0",
  "uptime": "28410.91",
  "temperature": "27.8",
  "connection": {
    "type": "wireless",
    "ssid": "ggxlan5"
  },
  "ip": "192.168.0.3"
}

The message can be used to display wihtin Home Assistant the status of the machine. The screenshot below depicts the sensors displayed in Home Assistant for four different machines and OS:

• A PC with Ubuntu
• A Raspberry Pi with Raspbian (Jessie)
• A Raspberry Pi with piCorePlayer
• An Odroid-XU4 with dietPi (Buster) To ease the integration with Home Assistant, MQTT discovery messages can be sent by the script sysinfo_MQTTtoHA.sh. All sensors for a machine can be attached to a device whose name is the hostname of the machine. It further eases the integration in Home Assistant: by selecting the device in Home Assistant configuration menu, a Lovelace card with all entities is ready to be inserted in one of the tabs.

Installation

It is assumed that an MQTT broker (e.g. mosquitto) is already installed on one of your computers ans is accessible through the local network.

mosquitto_pub and bc shall be available. For Debian based machine, they can be installed by the command sudo apt-get install bc mosquitto-clients.

Installation steps

1. Clone the repository or download the script on the machine.
2. Edit the script with a text editor and adjust the parameters to your configuration

• MQTT: the IP address of the broker, port, user and password (if needed)
• The topic prefix: the MQTT messages with system information are published in topic: mqtt_topic_prefix/hostname
• The Home Assistant discovery prefix (homeassistant by default as mentionned here)
• The prefix of the name of the sensors (if not set, hostname is used)
• The default parameters of the scripts: whether discovery messages shall be published or not, whether the MQTT messages with system information shall be sent once or repeatidly, the delay between each publishing. These three parameters can be overwritten by arguments on the command line

3. Run the script sh sysinfo_MQTTtoHA.sh(it is recommended to set the update rate to a low value e.g. 5s for intial test) and check if it is working properly:

• By checking the discovery messages are published by the command mosquitto_sub -h MQTTBrokerIP -t homeassistant/#/config
• By checking the MQTT messages with system information are periodically published by the command mosquitto_sub -h MQTTBrokerIP -t computers/+
• By checking a new device is available in Home Assistant (assuming the variable use_device is set to 1)
• By checking new entities are available in Home Assistant

4. If it works as expected, the script can be automatically launched as a service for machines supporting systemd. Run the script install_service.sh with the root priviledges: sudo sh install_service.sh. By default, a message is sent every minutes. To change the value, run the script with the argument -t nn where nn is a delay in seconds between the publishing of system information messages. (e.g. for one message every 5 minutes: sudo sh install_service.sh -t 300.

The status of the service (active/stopped) is reflected in Home Assistant: the entities are declared "unavailable" when the service is stopped (or the script no longer executed in loop mode)

active	stopped

Command line

To ease debug/investigations, the script sysinfo_MQTTtoHA.sh can be launched with some arguments:

• Argument -d:

  -d yes: MQTT discovery messages are published at the begining of the execution of the script

  -d no: MQTT discovery messages are not published

• Argument -r:

  -r no: the MQTT messages with the system information are not published

  -r once: the MQTT message with the system information is published once

  -r loop: the MQTT messages with the system information are published periodically

• Argument -t:

  -t nn: where nn is a number defining the delay (in seconds) between the publishing of messages with system information (only applicable with argument -r loop)