Control and Automate Docker Containers using Home Assistant

With this method, you can seamlessly interact with Docker containers running on a different machine (e.g., a virtual machine or physical server) using Home Assistant. Whether you need to start, stop, restart, or kill containers, this setup provides a simple way to control your containers using Home Assistant’s powerful automation system.

• start container
• stop container
• kill container
• restart container

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Step 1: Generate SSH Keys in Home Assistant

1. Install the SSH Add-on:

   • In Home Assistant, go to Settings → Add-ons → Add-on Store.
   • Search for Terminal & SSH, install it, and start it. Enable Start on boot and Watchdog.

2. Generate SSH Keys:

   • Open the Terminal & SSH add-on terminal.
   • Run these commands:

     mkdir -p /config/.ssh
     ssh-keygen -t ed25519 -f /config/.ssh/id_rsa -N ""

     • This creates a key pair without a passphrase (to avoid prompts).
     • Important: Use /config/.ssh, not /data/.ssh. This ensures the keys persist after updates.

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Step 2: Copy the Public Key to Your VM

1. Find Your Public Key:

   • In the SSH terminal, run:

     cat /config/.ssh/id_rsa.pub

   • Copy the output (it starts with ssh-ed25519 ...).

2. Add the Key to the VM (the VM where docker is installed):

   • SSH into your VM (from your local PC or HA terminal):

   • Note: You can use PuTTY to ssh to Home Assistant and the VM where Docker is installed.

     ssh user@vm-ip

   • On the VM, run:

     mkdir -p ~/.ssh
     echo "PASTE_YOUR_PUBLIC_KEY_HERE" >> ~/.ssh/authorized_keys
     chmod 700 ~/.ssh
     chmod 600 ~/.ssh/authorized_keys

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Step 3: Fix SSH Permissions

On Home Assistant:

• Ensure the private key has strict permissions:

  chmod 600 /config/.ssh/id_rsa

On the VM:

• Edit the SSH config file (/etc/ssh/sshd_config):

  sudo nano /etc/ssh/sshd_config

• Add/update these lines:

  PermitRootLogin no          # Disable root login (Optional)
  PasswordAuthentication no   # Disable password login
  PubkeyAuthentication yes    # Enable SSH keys

• Restart SSH:

  sudo systemctl restart sshd

  or

  sudo systemctl restart ssh

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Step 4: Test SSH Connection

• From Home Assistant’s SSH terminal, test:

  ssh -i /config/.ssh/id_rsa user@vm-ip

  • Replace user and vm-ip with your VM’s username and IP.
  • If it works, you’ll log in without a password. Type exit to quit.

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Step 5: Fix "Host Key Verification Failed"

This error occurs because Home Assistant doesn’t "trust" the VM’s SSH fingerprint. To fix it:

1. Manually Accept the Fingerprint:
   • Run this command once in the HA SSH terminal:

     ssh -o StrictHostKeyChecking=no -i /config/.ssh/id_rsa user@vm-ip "exit"

   • This adds the VM’s fingerprint to /root/.ssh/known_hosts in HA.

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Step 6: Update Home Assistant Configuration

1. Add shell_command:

   • In configuration.yaml, add:

     shell_command:
       docker_start_container_name: 'ssh -o StrictHostKeyChecking=no -i /config/.ssh/id_rsa user@vm-ip "docker start container_name"'
       docker_stop_container_name: 'ssh -o StrictHostKeyChecking=no -i /config/.ssh/id_rsa user@vm-ip "docker stop container_name"'
       docker_kill_container_name: 'ssh -o StrictHostKeyChecking=no -i /config/.ssh/id_rsa user@vm-ip "docker kill container_name"'
       docker_restart_container_name: 'ssh -o StrictHostKeyChecking=no -i /config/.ssh/id_rsa user@vm-ip "docker restart container_name"'
     

   • Replace user, vm-ip, and container_name.
   • This command disables host key checks and uses the correct key path. Once confirmed working, you COULD remove -o StrictHostKeyChecking=no.

2. Restart Home Assistant:

   • Go to Settings → System → Restart.

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Step 7: Create Automations

1. Create a Test Automation:
   • Go to Settings → Automations → Create Automation.
   • Use a simple trigger (e.g., time), and set the action to Perform Action → shell_command.docker_start_container_name.
   • Replace container_name.
   • Test it to see if the container starts.

example:

description: ""
mode: single
triggers:
  - trigger: state
    entity_id:
      - input_boolean.adguard_toggle
    from: "off"
    to: "on"
conditions: []
actions:
  - action: shell_command.docker_adguard_start
    data: {}

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Enjoy..

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