Azure IoT edge "Invalid image placeholder" after months of no changes - azure

Question

When trying to deploy my IoT edge modules, I get an error code 400 (Invalid config). Looking at the issue, it says Invalid image placeholder. Inside deployment.template.json, my module looks like this:
"modules": {
"sampleMod": {
"version": "1.0",
"type": "docker",
"status": "running",
"restartPolicy": "always",
"settings": {
"image": "${MODULES.sampleMod}", // This line has 'Invalid image placeholder' as an error
"createOptions": {}
}
}
}
This used to work. A couple of months ago, this file would work just fine, but now it doesn't. I can put an image URL there, and it works just fine, but since they change with every version it would be tedious to switch out the URL after every push.

Answer 1

I'm not sure when this behavior changed (July 12 is a good candidate, as that's the release date of IoT edge v1.3) but adding the architecture solved it for me. It's worth noting that my module dockerfile is named Dockerfile.arm64v8, as it was before this change.
"modules": {
"sampleMod": {
"version": "1.0",
"type": "docker",
"status": "running",
"restartPolicy": "always",
"settings": {
"image": "${MODULES.sampleMod.arm64v8}", // Add architecture here.
"createOptions": {}
}
}
}