How to use Mender-Convert to convert container image?

General Discussions
1

Hello everyone, I have been slowly but surely figuring out how this whole Mender thing works. I am currently in the process of converting a .img file after it has been created using dd. I am currently using a VMWare Ubuntu 22 virtual machine for this, but my end goal is to have this running on many desktop computers around the world, which will essentially work as servers.

I am confused on this specific step.
https://docs.mender.io/operating-system-updates-debian-family/convert-a-mender-debian-image#use-the-mender-convert-container-image

move overlay to the input folder

mkdir -p input/overlay
mv <PATH_TO_MY_OVERLAY>/* input/overlay/*

convert the image

MENDER_ARTIFACT_NAME=release-1 ./docker-mender-convert
–disk-image input/golden-image-1.img
–config configs/raspberrypi3_config
–overlay input/rootfs_overlay_demo/

First off, what is the overlay? I can’t find this mentioned anywhere else and am unsure what it is referring to.

–disk-image - This seems to just be the name of the disk image, simple enough.
–config - What would this be for a Debian based OS? I am not using Raspberry PIs in my setup at all.
–overlay input/rootfs_overlay_demo/ - I am confused on to what this is referring to.

My main question is figuring out what the overlay is. Could anyone guide me in the right direction? Thank you.

2

Hi @numanames,

nice to hear you’re making progress! Hope this helps you to proceed:

  • for a generic x86 linux distribution, you would start with this
  • the disk image is the binary image (as created via dd) of your golden device.
  • the overlay is essentially a file hierarchy that gets added to the resulting image. The README gives some examples of preparing overlays for using Hosted Mender, a demo server or a tenant token. Those should pretty much directly apply to x86 too.

Greetz,
Josef

EDIT: fixed link @numanames

3

Hello, thank you for your reply. I believe the first link you sent is broken as it doesn’t open anything for me. I am looking into the readme link you provided now.