Unable to load /config/known_devices.yaml: Config file not found: /config/known_devices.yaml

Configuration
1

I’ve been trying to set up an owntracks device tracker using an MQTT feed from Life360. I’m using the Life360 component from here:
https://github.com/arsaboo/homeassistant-config/blob/master/custom_components/sensor/life360.py

This is my config:

mqtt:
  embedded:
    listeners:
      default:
        max-connections: 5000
        bind: 192.168.1.36:1883
        type: tcp
      ws-1:
          bind: 192.168.1.36:8087
          type: ws
    auth:
      plugins: ['auth.anonymous']
      allow-anonymous: true
  broker: 192.168.1.36
  port: 1883
  
sensor:
  - platform: life360
    name: life360_ian
    username: "{mylife360username}"
    password: "{mylife360password}"
    client_id: 12345
    mqtt_topic: "life360/ian"
    scan_interval: 60

device_tracker:
  - platform: owntracks

These MQTT topics are being updated every minute or so (I’ve checked them using MQTT.fx):
life360/ian
owntracks/my name/my name
owntracks/my wifes name/my wifes name

I can see the life360_ian sensor icon at the top of my HA console (with a status of running), but the device tracker is not showing in the console, and known_devices.yaml is not being created - I get this error when HA starts:

Unable to load /config/known_devices.yaml: Config file not found: /config/known_devices.yaml

I’m running HA 0.65.0 in a Docker container on Lubuntu 16.10. I used this command to create my HA Docker container:

sudo docker run -d --name="home-assistant" -v ~/homeassistant:/config -v /etc/localtime:/etc/localtime:ro --net=host homeassistant/home-assistant

I modified the permissions on my config folder to 777, and changed ownership so that it is now:

# file: home/myuser/homeassistant (my homeassistant config folder)
# owner: homeassistant
# group: homeassistant
user::rwx
group::rwx
other::rwx

Can anyone advise on why known_devices.yaml isn’t being created, and why my device tracker can’t be seen in my HA console?

2

I just created another device_tracker as an experiment - using the ASUSWRT platform. After adding that device_tracker the known_devices.yaml file was created fine, and was populated with all of the devices connected to my Asus router. It’s just the owntracks device tracker (updated using the life360 component) that is not creating the known_devices.yaml file (and is not updating the file created by the ASUSWRT device tracker either.

3

Have also just noticed this in my log on the HA console - does this give any clues?

Log Details (ERROR)
Wed Mar 14 2018 14:52:35 GMT+0000 (GMT Standard Time)

Error doing job: Task exception was never retrieved
Traceback (most recent call last):
  File "/usr/local/lib/python3.6/asyncio/tasks.py", line 180, in _step
    result = coro.send(None)
  File "/usr/local/lib/python3.6/site-packages/hbmqtt/broker.py", line 342, in stream_connected
    yield from self.client_connected(listener_name, StreamReaderAdapter(reader), StreamWriterAdapter(writer))
  File "/usr/local/lib/python3.6/site-packages/hbmqtt/broker.py", line 476, in client_connected
    yield from self.publish_retained_messages_for_subscription(subscription, client_session)
  File "/usr/local/lib/python3.6/site-packages/hbmqtt/broker.py", line 723, in publish_retained_messages_for_subscription
    handler.mqtt_publish(
AttributeError: 'NoneType' object has no attribute 'mqtt_publish'