[Bug]: Incorrect calculation of cronjobs in scheduled backups

[DeskPlant]

Is there an existing issue already for this bug?

• [X] I have searched for an existing issue, and could not find anything. I believe this is a new bug.

I have read the troubleshooting guide

• [X] I have read the troubleshooting guide and I think this is a new bug.

I am running a supported version of CloudNativePG

• [X] I have read the troubleshooting guide and I think this is a new bug.

Contact Details

patrik.zotj@gmail.com

Version

1.22.2

What version of Kubernetes are you using?

1.29

What is your Kubernetes environment?

Cloud: Amazon EKS

How did you install the operator?

YAML manifest

What happened?

After creating a cluster, i tried attaching a scheduled backup resource to it using the yaml below.

apiVersion: postgresql.cnpg.io/v1
kind: ScheduledBackup
metadata:
  name: backup-test
spec:
  schedule: "0 1 * * *"
  backupOwnerReference: self
  immediate: true
  cluster:
    name: test-db

The backups created by it are fine, the issue is the frequency of the backups does not match the given cron in the yaml file. For examle if i give it a cronjob to backup every day at 1 am, even though it says the schedule is correct when i use kubectl describe, the backups are instead done every 1 hour.

I have tried this with other formats for example every 8 hours and that makes the backups occur every 8 minutes instead.

Cluster resource

No response

Relevant log output

No response

Code of Conduct

• [X] I agree to follow this project's Code of Conduct

[mv-yurchenko]

Got same problem with cron error

[shusaan]

I am facing same problem

[shusaan]

@gbartolini is that targeting in next release ?

[mv-yurchenko]

May be this will help: https://pkg.go.dev/github.com/robfig/cron I used this doc to configure

[shusaan]

May be this will help: https://pkg.go.dev/github.com/robfig/cron I used this doc to configure

thank you, will check and share update

[ccrvlh]

The issue seems to be that CNPG uses a 6 string cron as defined on the link on the docs (https://pkg.go.dev/github.com/robfig/cron). However, the docs mention:

This field is a cron schedule specification, which follows the same format used in Kubernetes CronJobs

And when looking at k8s CronJob docs here It says that is a 5 digit string cron.

The .spec.schedule field is required. The value of that field follows the Cron syntax:

So the issue doesn't seem to be that is calculating it wrong, but rather that the docs/links/logic are inconsistent.