How to create a container based on image downloaded into a specific repo?


There is a project that was inserted into a repository from its university and I need to test this project. Basically, this project involves some technologies, and LXC/LXD is one of them. There is an image called “MQTT_Publisher.img” which is an application responsible for generate random values of temperature and send them to a MQTT Gateway. This MQTT_Publisher.img is the image used in a LXC/LXD container. Now, for testing this project, I downloaded this image and I need to create a container based on it.

How can I create a container based on an image that I’ve downloaded? I’ve searched about it, but I had obtained results about images like Ubuntu, Debian, and other ones that are available in default LXC/LXD repositories. But my image is an ready application that I need to use to create the container. I’ve tryed to add a remote server with the repository address of the university which contains the image, but it didn’t work. So, do I need to put this MQTT_Publisher.img in some specific repository in order to use it to create a container? Or there is another way to access this image donwloaded in my computer to create the container? Can I use an image in my computer by using a command with its directory folder instead putting it in a remote repository? What are the commands needed for doing it?

Thank you.

LXD images are usually tarballs, not .img, so we’d first need to know exactly what that MQTT_Publisher.img thing is.

Can you run file MQTT_Publisher.img?