---
title: "Comment by Hayrullah Kar on \"I Didn't Need a DAG. I Needed Cron.\" | Hashnode"
description: "Discovering the inventory from the Proxmox API instead of hard-coding it is the best decision in here, and it quietly creates the one failure this design cannot"
url: "https://hashnode.com/posts/i-didn-t-need-a-dag-i-needed-cron/6ab7d66877c34ddd5492fbe1/comment/6ab92e4d316804f393c1e733"
---

[Discussion](https://hashnode.com/posts/i-didn-t-need-a-dag-i-needed-cron/6ab7d66877c34ddd5492fbe1)

Comment [I Didn't Need a DAG. I Needed Cron.](https://hashnode.com/posts/i-didn-t-need-a-dag-i-needed-cron/6ab7d66877c34ddd5492fbe1)

[Hayrullah Kar](https://hashnode.com/@magesheet)

[Sep 27](https://hashnode.com/posts/i-didn-t-need-a-dag-i-needed-cron/6ab7d66877c34ddd5492fbe1/comment/6ab92e4d316804f393c1e733)

Discovering the inventory from the Proxmox API instead of hard-coding it is the best decision in here, and it quietly creates the one failure this design cannot see.

A job never names a host, it selects. So the scope of every job is a function of tags that live in a different repository and change for reasons unrelated to the job. Rename a tag in Terraform, drop one while refactoring a stack, or fat-finger it in a new guest's definition, and the job stops covering that guest. Nothing fails. nr exec fans out to eleven guests instead of twelve, every one of them succeeds, the job exits 0 and the Slack channel stays quiet. Silence is what you built the whole system to mean "everything is fine".

[Wilhelm Murdoch](https://hashnode.com/@wilhelm-codes)

[Sep 27](https://hashnode.com/posts/i-didn-t-need-a-dag-i-needed-cron/6ab7d66877c34ddd5492fbe1/comment/6ab92e4d316804f393c1e733#reply-6ab92fdd8440cc254038cd1c)

Ha, excellent catch! You're exactly right. Silence is the signal and a guest quietly falling out of a tag selector produces exactly that. It's softer than it sounds for the jobs I run today, since they select everything and opt guests out with `exclude`, so a new or renamed guest fails loudly. But the moment I write a tag-scoped job, your scenario is live. I'm adding an `expect` floor per job and a daily coverage job that lists any guest no job touches. I'll update the article on my blog accordingly and credit you for pointing this out. Thanks for this!

[Hayrullah Kar](https://hashnode.com/@magesheet)

[Oct 19](https://hashnode.com/posts/i-didn-t-need-a-dag-i-needed-cron/6ab7d66877c34ddd5492fbe1/comment/6ab92e4d316804f393c1e733#reply-6ad60cae216b44355a598d98)

Select-all with exclude is a good default exactly because a new guest fails loudly, and I had missed that you were already doing it. The expect floor and the coverage job cover the two directions well: a job seeing fewer hosts, and a host no job sees. One small thing: if the coverage job stops running, it goes quiet the same way, so it is worth having it post a short all-clear line each day so its absence is noticed.