My hand built MQTT devices are unavailable after restart but zigbee2mqtt ones are


I have tried looking for answers to my questions but have failed. Apologies if this has been covered elsewhere…

A few years ago I hand crafted a Raspebrry PI based multi-zone irrigation system for my garden which I controlled from an inbuilt web interface on the device.

I have plans to expand my home automation so decided it would be far better if I used a home automation server and rewrote my irrigation device to work with that. I chose as I wanted maximum flexibility and I liked the idea of a non-cloud based solution.

I rewrote my PI based irrigation device (in python) to be an MQTT client publishing and subscribing to a set of topics that describe and control the state of each watering zone. I publish availiabilty and state topics and subscribe to a command topic for each zone.

All this I have working with HA 0.110.4 on very latest production hassos 4.8. running on (another) PI 3b. I am using the mosquito broker v 5.1 and all is working ‘tickty boo’ except for a couple of things.

  1. I have manually created entries in my configuration.yaml for my irrigation switches as well as some sensors (inc temperature) that I have installed. ( I may go for auto discovery once I have the basic set-up working but not yet). All of my hand-crafted ‘devices’ appear as entities within HA but not devices - why?

Incidentally I have also installed the zigbee2mqtt add on and have auto discovered a zigbee (OSRAM smart+ plug) device. This correctly appears as a device within HA so I must be missing something!

  1. in my irrigation device I publish and subscribe to the appropriate topics in the client.on_connect() callback which is called once the client-broker connection is established. I have coded my device client according to the paho-mqtt guidelines, using loop_start() and loop_stop() methods on the MQTT client class which runs a background threat so as to re-estabilsh the MQTT broker - client connection if it is lost.

During development I am forever restarting after editing configuration.yaml. The presence of the zigbee2mqtt Smart+ plug doesnt seem to be affected by these restarts of HA (and therefore the broker) but all the ‘entities’ I have created for my irrigation server appear unavilable in HA. What am I doing wrong?

I am pretty sure I could overcome this issue by publishing availability of my devices evey 5 minutes from my irrigation server but this feels wrong. I am suprised that either the client.on_connect() callback isnt called again on reestablishing the connection or the loss of connection (which must be detected in the irrigation client) isnt rippled up to my ‘application’ code so I could take steps to re-publish and subcribe to my topics.

Happy to share configurtion.yaml and or client MQTT code if required and thanks in advance for any help /guidance you can offer.


If you want to define devices, you will have to use MQTT Discovery. Whatever MQTT sensors, switches, lights, etc that you manually define in configuration.yaml (and related files) do not accept device-related data. It states that in the device option:

Information about the device this binary sensor is a part of to tie it into the device registry. Only works through MQTT discovery and when unique_id is set.

If you wish, you can use scripts to create entities and devices via MQTT Discovery. I provided examples in these posts:

It sounds like your irrigation server is not publishing its messages using the retained flag.

When a message is published to a topic with the retained flag, it instructs the MQTT Broker to store (retain) the message. Any MQTT client that subscribes to that topic will receive the retained message (even if the subscriber connects to the broker after the message was published).

If the message is not published with a retain flag, MQTT clients that subscribe to the topic after the message was published will receive nothing. Home Assistant is an MQTT client and, after a restart, it connects to the MQTT Broker and subscribes to all topics of interest. It receives all retained messages and for those topics whose messages were not retained, it receives nothing (i.e. unavailable).

Given that you are the author of the irrigation server’s software, you can easily change the code so the messages are published using the retained flag.

Zigbee2mqtt publishes retained messages (that’s why they are available upon restart). You can confirm that by connecting to the MQTT Broker using a client like MQTT Explorer which indicates which topics do/don’t have retained messages.


@123 Kudos for the detailed and helpful reply, it’s nice when people take the time for these


Many many thanks for your help! Using the details of your scripts I was easily able to get my config topics published from my python base Irrigation Server. MQTT discovery now works a treat! All my irrigation entities are now being associated with a newly created irrigation server device - thank you!

One point, I publish the (same) config topics every time my server boots - is that good practice?

However, I am still having difficulty with state persistence my entities in HA over restarts of HA even though I an now setting retain-True whenever I publish avaialbility and state.

Using the most excellent MQTT Explorer app you pointed me to (thank you), I can see that the last values I published to my topics are being preserved in the Mosquitto broker even across restarts of HA (the mosquitto broker is an add-on to HA) but still the entities appear as unavailable in the HA Lovelace UI after a restart?

PS: The MQTT Explorer showed me the broker was persisting a whole range of topics and values from various itterations of my Irrigation Server and was also very useful in purging unused items .

TIA again for further assistance!


I don’t see anything wrong with that. However, they should be published as retained messages. Otherwise, when Home Assistant restarts, it is presented with the conundrum that an entity is registered in the entity registry but now it has no configuration information available via MQTT Discovery.

Does rebooting the Irrigation Server fix it?

What are you publishing for availability?

Wow - thanks for the quick response!

I do publish the config with retain=True.

Rebooting the irrigation server does fix the persistence issue but the MQTT Explorer shows the retained messages even if I dont?

Payloads for available/not available are “online” and “offline” respectively.


If you are publishing retained messages to all topics:

  • the entity’s discovery topic (i.e. its configuration)
  • the entity’s state_topic (i.e. its state value)

then when Home Assistant restarts and re-subscribes to those topics, it gets the entity’s configuration and its state. The only window of opportunity for the entity’s state to be unavailable is the moment before Home Assistant connects to the broker and re-subscribes to the entity’s state_topic (which is a very short period of time).

If you say it reports unavailable until you restart the Irrigation Server, that’s much longer than a mere moment in time and something else is causing it, possibly the availability_topic. Are offline and online published as retained messages?

Thank you so much - that sorted it - I thought I published everyting with retain=True but I was mistaken. I do now and it is all working as I would want it to!

You have helped me enormously - I am really grateful.


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Just as an aside if you publish ‘command’ payloads these should not be sent ‘retained’.

The reason is that if you re-subscribe to a broker then you would receive the commands again if they were retained - and they would be actioned again even if they were originally sent a long time ago.

Thx xAPPO - I understand!

Can you, or maybe Taras, tell me how you specified everything with retain=True please? I have this code based on the script that Taras created. I thought I was specifying that the messages are retained but after I restart HA, the switch is unavailable, until I press it in my dashboard. Do I need to add retain=True in to the Payload as well?

service: mqtt.publish
  topic: homeassistant/switch/entertainment/config
  retain: true
  payload: |
      "name": "Entertainment",
      "unique_id": "entertainment",
      "state_topic": "stat/entertainment/POWER",
      "command_topic": "cmnd/entertainment/POWER",
      "payload_on": "ON",
      "payload_off": "OFF",
      "state_on": "ON",
      "state_off": "OFF"

I believe that means when the physical switch publishes its state to stat/entertainment/POWER it isn’t publishing it as a retained message.

Ah! So it’s the device itself that needs to be investigated. I thought the broker would remember the state from HA. I’ll look in to that, thanks.

Home Assistant doesn’t publish to the state_topic (in this case it’s stat/entertainment/POWER), that’s the device’s task (to report its current state).

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The broker only retains the state if the message had the retain flag set by the device that published the message.