How to fail early?

[gcb]

cloud-init does some really insane things by default, like "cannot find package, just ignoring *shrug". How can i just have it crash then and there instead?

[holmanb]

How to fail early?

Lets start with: Why to fail early?

cloud-init does some really insane things by default, like "cannot find package, just ignoring *shrug".

No, it doesn't ignore. You seem to have overlooked the error states that cloud-init presents when package install fails.

How can i just have it crash then and there instead?

Why do you want that? And more importantly, why do you think that "crash immediately on first failure" is the best behavior for all cloud-init users?