I'm trying to add an Active Directory service to macOS image. I know how to bind AD on a Mac but I was looking for an automated way to do it for a large deployment 50–100 Macs, i.e add it in an image profile. What's the best practice for this?
Depends on how you created the image.
If you're using the installer as your source then there's a pane for adding directory servers.
If you're using an installed system as the source then you may have to use something like the dsconfigad command in a script to bind.