see https://docs.docker.com/engine/install/debian/. This is done by adding the docker repository.

# Add Docker's official GPG key:
sudo apt-get update
sudo apt-get install ca-certificates curl
sudo install -m 0755 -d /etc/apt/keyrings
sudo curl -fsSL https://download.docker.com/linux/debian/gpg -o /etc/apt/keyrings/docker.asc
sudo chmod a+r /etc/apt/keyrings/docker.asc

# Add the repository to Apt sources:
echo \
  "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.asc] https://download.docker.com/linux/debian \
  $(. /etc/os-release && echo "$VERSION_CODENAME") stable" | \
  sudo tee /etc/apt/sources.list.d/docker.list > /dev/null
sudo apt-get update

then install docker sudo apt-get install docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin

Then run the hello world container sudo docker run hello-world the command looks for the hello world container on the raspberry and if not found it down loads it from the docker hub.

To have docker running as none root,

newgrp docker inform the system that the docker group has changed

Add the user to the docker group so it can connect to docker sudo usermod -aG docker $USER

Logout and login again and run docker run hello-world

To run it decide the values for:

TZ=<time zone>

Path where the home assistant docker configuration goes.

Then create this directory sudo mkdir -p /opt/docker/homeassistant

Give permission for the local user

sudo chown -R $(id -u):$(id -g) /opt/docker/homeassistant

docker run -d --name homeassistant --privileged --restart=unless-stopped -e TZ=Europe/Zurich -v /opt/docker/homeassistant:/config -v /run/dbus:/run/dbus:ro --network=host ghcr.io/home-assistant/home-assistant:stable

If successful docker starts and since home-assistant docker container is not on the local machine it gets downloaded from docker hub and this takes a while.

--network=host makes that the local machines IP address can be used and not the docker one showed by sudo ifconfig

The above docker command installs and runs homeassistant but to have this done automatically next startup a systemd file needs to be created: sudo touch /etc/systemd/system/homeassistant.service

[Unit]
Description=Home Assistant Container
Requires=docker.service
After=docker.service

[Service]
Type=oneshot
RemainAfterExit=yes
WorkingDirectory=/opt/docker/homeassistant
ExecStart=/usr/bin/docker run -d --name homeassistant --privileged --restart=unless-stopped -e TZ=Europe/Zurich -v /opt/docker/homeassistant:/config -v /run/dbus:/run/dbus:ro --network=host ghcr.io/home-assistant/home-assistant:stable
ExecStop=/usr/bin/docker stop -t 60 homeassistant
ExecStopPost=/usr/bin/docker rm -f homeassistant

[Install]
WantedBy=multi-user.target

docker ps -a check if docker still runs homeassistant

docker stop homeassistant stop it

docker rm homeassistant remove temporary files

sudo systemctl daemon-reload make the system aware of the new service

sudo systemctl enable homeassistant.service tell it to start it automatically next boot

sudo systemctl start homeassistant.service start it manually

sudo systemctl status homeassistant.service check its status

sudo journalctl -u homeassistant.service -f check its log

to update homeassistant

Stop the service sudo systemctl stop homeassistant.service

get the update docker pull ghcr.io/home-assistant/home-assistant:stable it will also tell if there is an update

docker rm homeassistant remove temporary files

sudo systemctl start homeassistant.service start it again

Automations is the logic added to Home Assistant that takes inputs or events and controls outputs or actions. It is what Home Assistant does automatically. Automations have triggers.

Automations can be created and edited via the gui or yaml.

The following example turns on an output of a tasmota device at 8 o'clock:

alias: Tasmota Switch On at 20:00
description: Turn on switch.tasmota2 at 20:00
trigger:
  - platform: time
    at: "20:00:00"
action:
  - service: switch.turn_on
    target:
      entity_id: switch.tasmota2
    data: {}

Or turn it on at sunset:

alias: Tasmota Switch On at sunset
description: Turn on switch.tasmota2 at sunset 
trigger:
  - platform: sun
    event: sunset
    offset: "0"
condition: []
action:
  - service: switch.turn_on
    target:
      entity_id: switch.tasmota2
    data: {}
mode: single

And a humidity alarm:

alias: Humidity Alarm Bathroom On
description: Humidity is above level
trigger:
  - platform: numeric_state
    entity_id: sensor.shellyplusuni_a0a3b36865f4_humidity
    above: 45
condition: []
action:
  - type: turn_on
    device_id: f9ecf0bcd602949c51a780527ac19b57
    entity_id: switch.shellyplusuni_a0a3b36865f4_switch_0
    domain: switch
mode: single

It is assumed that a MQTT broker as mosquitto is running and configured in Home Assistant running.

#! /bin/bash
mosquitto_pub -t "raspi/soc/temperature" -m "$(/usr/bin/vcgencmd measure_temp | sed -E "s/temp=([0-9]+\.[0-9]+).*/\1/")" -u <username> -P <password>

mqtt:
  sensor:
    - name: "raspi_soc_temperature"
      state_topic: "raspi/soc/temperature"

sensor:
  - name: "raspi_soc_temperature"
    state_topic: "raspi/soc/temperature"
  - name: "raspi_manager_battery_soc"
    state_topic: "raspi/manager"
    value_template: "{{ value_json['battery' ].soc }}"
  - name: "raspi_manager_power"
    state_topic: "raspi/manager"
    value_template: "{{ value_json.power }}"

switch:
  - name: "mini1pmg3"
    command_topic: "shelly1pmminig3-5432044f7414/rpc"
    payload_on:  '{"id": 1, "src": "hass", "method":"Switch.Set", "params":{"id":0,"on":true}}'
    payload_off: '{"id": 1, "src": "hass", "method":"Switch.Set", "params":{"id":0,"on":false}}'
    retain: false

switch:
  - name: "mini1pmg3"
    command_topic: "shelly1pmminig3-5432044f7414/rpc"
    payload_on:  '{"id": 1, "src": "hass", "method":"Switch.Set", "params":{"id":0,"on":true}}'
    payload_off: '{"id": 1, "src": "hass", "method":"Switch.Set", "params":{"id":0,"on":false}}'
    retain: true
    state_topic: "shelly1pmminig3-5432044f7414/status/switch:0"
    value_template: "{{ value_json.output }}"
    state_on: true
    state_off: false

unique_id: "raspi4_soc_temp-e45f016dc555"

unit_of_measurement: "W"