Custom Monitor Docker component for Home Assistant

About

This repository contains the Monitor Docker component I developed for monitoring my Docker environment from Home-Assistant. It is inspired by the Sander Huisman Docker Monitor, where I switched mainly from threads to asyncio and put my own wishes/functionality in. Feel free to use the component and report bugs if you find them. If you want to contribute, please report a bug or pull request and I will reply as soon as possible.

Monitor Docker

The Monitor Docker allows you to monitor Docker and container statistics and turn on/off containers. It can connected to the Docker daemon locally or remotely. When Home Assistant is used within a Docker container, the Docker daemon should be mounted as follows -v /var/run/docker.sock:/var/run/docker.sock.

Docker run Example

docker run -d \
... \
-v /var/run/docker.sock:/var/run/docker.sock \
  homeassistant/home-assistant

docker-compose.yaml Example

services:
  hass:
    image: homeassistant/home-assistant
...
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock
...

NOTE: Making /var/run/docker.sock read-only has no effect, because it is a socket (and not file).

Raspberry Pi (Raspbian)

Using a Raspberry Pi with Raspbian it could happen no memory is reported. In such case the Docker API does not report it to Monitor Docker. Making the following changes, normally fixes the problem:

• Open the file /boot/cmdline.txt
• Add the following to the end of the existing line cgroup_enable=cpuset cgroup_memory=1 cgroup_enable=memory
• Reboot your Raspberry Pi

NOTE: Add the line to the existing line, do not replace it

Ubuntu / Debian

Also on Ubuntu/Debian it is possible no memory is shown, the following changes could solve your problem:

• Open the file /etc/default/grub
• Modify the GRUB_CMDLINE_LINUX_DEFAULT="" to GRUB_CMDLINE_LINUX_DEFAULT="quiet cgroup_enable=memory swapaccount=1"
• Run sudo update-grub
• Reboot your Ubuntu/Debian

NOTE: This is untested, use at your risk

Installation

HACS - Recommended

• Have HACS installed, this will allow you to easily manage and track updates.
• Search for 'Monitor Docker'.
• Click Install below the found integration.
• Configure using the configuration instructions below.
• If applicable, add the volume /var/run/docker.sock to your Home Assistant container.
• Restart Home-Assistant.

Manual

• Copy directory custom_components/monitor_docker to your <config dir>/custom_components directory.
• Configure with config below.
• If applicable, add the volume /var/run/docker.sock to your Home Assistant container.
• Restart Home-Assistant.

Configuration

To use the monitor_docker in your installation, add the following to your configuration.yaml file:

# Example configuration.yaml entry
monitor_docker:
  - name: Docker
    containers:
      - appdaemon
      - db-dsmr
      - db-hass
      - deconz
      - dsmr
      - hass
      - influxdb
      - mosquitto
      - nodered
      - unifi
    rename:
      appdaemon: AppDaemon
      db-dsmr: "Database DSMR-Reader"
      db-hass: Database Home Assistant
      deconz: DeCONZ
      dsmr: "DSMR-Reader"
      hass: Home Assistant
      influxdb: InfluxDB
      mosquitto: Mosquitto
      nodered: "Node-RED"
      unifi: UniFi
    monitored_conditions:
      - version
      - containers_running
      - containers_total
      - state
      - status
      - memory

Configuration variables

Debugging

It is possible to debug the Monitor Docker component, this can be done by adding the following lines to the configuration.yaml file:

logger:
  logs:
    custom_components.monitor_docker: debug

Q&A

Here are some possible questions/errors with their answers.

1. Question: Does this integration work with the HASS or supervisord installers?
   Answer: Yes, with an external docker container. Home Assistant supervised does not expose the Docker UNIX/TCP socket. However, you can use an external docker container named docker-socket-proxy. Start this docker with the following docker-compose code. It exposes the socket over TCP and monitor_docker can listen to it.

   # Proxy the Docker sock so that we can pick up stats for HomeAssistant
   dockerproxy:
     image: tecnativa/docker-socket-proxy
     container_name: dockerproxy
     privileged: true
     volumes:
       - /var/run/docker.sock:/var/run/docker.sock
     ports:
       - 2375:2375
     environment:
       - BUILD=1
       - COMMIT=1
       - CONFIGS=1
       - CONTAINERS=1
       - DISTRIBUTION=1
       - EXEC=1
       - IMAGES=1
       - INFO=1
       - NETWORKS=1
       - NODES=1
       - PLUGINS=1
       - SERVICES=1
       - SESSSION=1
       - SWARM=1
       - POST=1
   

   Add the following to your configuration.yaml:

    monitor_docker:
      - name: Docker
        url: tcp://<host_ip>:2375

2. Error: Missing valid docker_host.Either DOCKER_HOST or local sockets are not available.
   Answer: Most likely the socket is not mounted properly in your Home Assistant container. Please check if you added the volume /var/run/docker.sock
3. Error: aiodocker.exceptions.DockerError: DockerError(900, "Cannot connect to Docker Engine via tcp://10.0.0.1:2376...).
   Answer: You are trying to connect via TCP and most likely the remote address is unavailable. Test it with the command docker -H tcp://10.0.0.1:2376 ps if it works (replace 10.0.0.1 with your IP address)
4. Question: Is Docker TCP socket via TLS supported?
   Answer: Yes it is. You need to set the url to e.g. tcp://ip:2376 and the environment variables DOCKER_TLS_VERIFY=1 and DOCKER_CERT_PATH=<path to your certificates> need to be set
   The following is a docker-compose example how to set the environment variables and the volume with the certificates:

services:
  hass:
    image: homeassistant/home-assistant
...
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock
      # The files need to be named "cert.pem" and "key.pem"
      - ./certs:/certs
    environment:
      - DOCKER_TLS_VERIFY=1
      - DOCKER_CERT_PATH=/certs
...

5. Question: Can this integration monitor 2 or more Docker instances?
   Answer: Yes it can. Just duplicate the entries and give it an unique name and define the url as shown below:

# Example configuration.yaml entry
monitor_docker:
  - name: Docker
    containers:
    ...
  - name: RemoteDocker
    url: tcp://10.0.0.1:2376
    containers:
    ...

NOTE: The integration supports multiple Docker instances, but you can only define 1 TLS configuration which is applied to all (thus you cannot mix TCP with and without TLS).
6. Question: Can create, delete or re-create of a container be implemented in the integration?
Answer: The used Docker library has no easy (and safe) way to handle such functionality. Please use docker-compose to handle such operations. If anybody can make this fully work in a safe way, I'll be happy to merge the PR
7. Question: Can you add more security to a switch?
Answer: No, this isn't possible from the integration. You need to do this directly in Lovelace itself, within the card e.g. https://github.com/iantrich/restriction-card
8. Question: All the reported memory values are 0 (zero), can this be fixed in the integration?
Answer: No, the integration just uses the available information from the API and you should fix your Docker
9. Question: Is it possible to monitor HASS.IO?
Answer: Yes, please use the Docker Socker Proxy https://github.com/Tecnativa/docker-socket-proxy and configure tcp://ip:port to connect to the proxy. This has been tested and verified by other users, but I cannot give support on it.
10. Question: I get a permission denied error?
Answer: In general Docker and HASS.IO are running as root and always can connect to /var/run/docker.sock. If you run in a venv environment or directly with Python, you may need to add the "docker" group to the user used for Home Assistant. The following commands may help you, and it is recommended to reboot after "usermod":

$ sudo usermod -a -G docker <user>
$ sudo reboot

11. Question: Can you add the feature to check if there are updates to images in e.g. hub.docker.com?
    Answer: Such feature goes outside of the scope of monitor_docker and there are few other options available for this. You can use https://newreleases.io or https://github.com/crazy-max/diun/
12. Question: Is Docker via SSH supported?
    Answer: No, the Docker library used, does not support it. There is a small but, maybe you can get it to work via socat. The following URL may help you: https://serverfault.com/questions/127794/forward-local-port-or-socket-file-to-remote-socket-file/362833#362833

Credits

• Sanderhuisman

License

Apache License 2.0