My problems with using VMs and ZDM

Hi Zerynth Support Team!

I have four questions about using VMs and ZDM.

  • The first question:
    I tried to create a new FOTA enabled VM on my ESP32 custom board, but I couldn’t do it because I have already used 5 free premium licenses before.
    Regarding the profile, I have only 5 available Starter license and 0 available Premium license.
    Here is my Zerynth profile.

    So I removed all VMs and temp files in the zerynth2 directory and tried to create the FOTA enable VM on the board. However, unfortunately, I couldn’t also do it.

    I’d like to know how to reuse the free premium licenses. Otherwise, can they be used only once?
    Once I’ve built five fota enabled VMs on a board before, can’t I ever make fota enabled VM anymore even if I remove them on my pc? Or isn’t any way to use the fota enabled VM except for buying the premium license?

  • The second question:
    If I need to use Zerynth Device Manager, is it necessary to install Zerynth OS on the board while creating VM? I want to use ZDM only for fota feature.

  • The third question:
    In the documentation, I see ZDM can interface with the custom IoT project.

    I have a Django web server that manages my custom boards. It’s running on the Raspberry Pi4.
    I want to control the fota process on the web server. Is it really possible to access from the web server to ZDM API? If it’s possible, would you like to suggest me any similar examples or guides?

  • The fourth question:
    I’d like to run the ZDM site as a docker container like grafana or database or mqtt.
    Is there docker image for ZDM?

Sorry for too many questions, but I really hope you get back to me with good solutions and advices.
Best regards.


Hi @Anatoli_Juny

Each licenses can be used for a specific device.
Looking at the screenshot of your licenses, you have used 6 out of 6 free premium licenses; on ESP32 devkit c and on Huzzah32.
If you want more licenses Feel free to purchase the needed amount :
At the website you will find the pricing and also button to contact our sales team to purchase the licenses.

Yes, specifically you need to register the device then create and use a FOTA enabled VM for each device.

Currently, ZDM supports web hooks to forward you data to your preferred cloud service, but soon we will have APIs and more webhook features, However the features you mentioned can be custom developed for you for low cost fee if you are interested.

Zerynth provides this feature as a non recurrent fee, If you are interested in using this in your product, Please contact the sales team for more information.

Hi @karimhamdy1

Thanks for your reply.
As for the first answer, it means that it’s possible to use free fota enabled VM again if I use the previous boards(ESP32 DevkitC and Huzzah32) I have already installed the fota enabled VM?

As for the second answer, I know it’s necessary to register the device and create the fota enabled VM on it to use Fota feature.
I just wanted to know if it’s also necessary to install Zerynth OS for fota. I don’t think I have to click “Zerynth OS” button to use the fota function by zdm. Could you make it more clear?

Thanks in advance.

Yes, The VM is made for a specific device and can work indefinitely on it.

The install OS has a note that the quick procedure will install the basic version of the OS, to use the fota you need FOTA enabled VM, so instead please create an appropriate VM with FOTA features and virtualize this VM.