Cron Timer, Renewal, adjust trigger?

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I just upgraded from Let’sEncrypt to Certbot, following the instructions at

It worked, thank you very much!

Now I have two questions about the Cron / Timer job which was installed to auto update certs.

1: Why does this run twice a day, if auto renews are attempted if cert is expiring within 30 days?
In my “lean” mindset, that seems like a waste of resources.

2: Can the cron job trigger be changed to weekly, and how?

using $ ps -p1 #comment: ( number 1 not letter l)
I see I am using systemd timers, not cron jobs.

I found 3 certbot.timer files:
(both files are identical)
(this file is blank)

? 2a: Which of those files do I edit to change the Calendar trigger to weekly?

Note to others reading this: after editing timer, reload daemon


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There are a few reasons it runs frequently:

  • So that all of your certificates don’t bunch up and renew at the same time. That would make load spikier for you and for Let’s Encrypt, and would have implications with the rate limits.

  • The more attempts it makes to renew a certificate, the less likely it is for a temporary outage to allow a certificate to expire.

  • Partly for the sake of features that may exist in the future, like OCSP stapling management (which is under development), or automatically renewing revoked certificates.

It’s not that expensive for Certbot to run, examine all your certificates, see that none of them need to be renewed, and exit.

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