What is difference between repo_upgrade and package_upgrade and apt_upgrade on cloud-init?

Question

In an example from AWS EC2 manual shows that we can perform apt update and upgrade by putting:

repo_update: true
repo_upgrade: true

But I can't find exactly same commands in cloud-init official documentation, so I keep looking for the similiar commands and found this, they give two commands package_upgrade and apt_upgrade but didn't tell the difference.

It makes me curious that what's the difference between repo_upgrade and package_upgrade and apt_upgrade

Answer 1

What I managed to find is

repo_upgrade description

(the source is Security updates section of Package repository topic - the official AWS Documentation)

package_update: (boolean) Set true to update packages. Happens before upgrade or install. Default: false. package_upgrade: (boolean) Set true to upgrade packages. Happens before install. Default: false. apt_update: (boolean) DEPRECATED: Dropped after April 2027. Use package_update. Default: false. apt_upgrade: (boolean) DEPRECATED: Dropped after April 2027. Use package_upgrade. Default: false. (see more details here)

Answer 2

Yes this is quite puzzling, until I stumbled upon this, from which it seems that repo_upgrade applies to Amazon Linux only.

Also I found this ancient fan-made example.

It seems that most of the explanations are correct.