certbot — certificate issuance and renewal

💬 "certbot command"

certbot issues and renews free certificates. In practice, checking the state of renewal automation is essential.

Use renew --dry-run to verify in advance whether renewal will actually succeed.

• Concept: Issues and renews certificates using the ACME protocol.
• renew: Renews certificates nearing expiration.
• timer: Automatic renewal runs through a systemd timer.
• dry-run: Tests whether renewal can succeed without actually performing it.

Commonly used options

3 essential command combinations

• certbot certificates — Check the certificate list and expiration dates
• certbot renew --dry-run — Verify that automatic renewal succeeds
• systemctl list-timers | grep certbot — Check the automatic renewal timer

💬 "Show me an example of connecting this to alert automation"

Here are the situations commonly encountered on live production servers, organized in order.

Step 1 · Certificate status

Check expiration dates and target domains.

certbot certificates

Step 2 · Renewal test

Verify that renewal can succeed before actually renewing.

certbot renew --dry-run

Step 3 · Timer check

Check whether automatic renewal is scheduled.

systemctl list-timers certbot.timer --no-pager

How this is used in practice

1. Guarding against automatic renewal failure

Situation — Renewals can fail silently and put you at risk of expiration.

certbot renew --dry-run

Result — If verification fails, the cause (webroot path, firewall, DNS) is printed.

Key point — Add a dry-run check to your monthly routine.

2. Checking the certificate list

Situation — You need to see expiration dates for multiple domain certificates at once.

certbot certificates | grep -E 'Certificate Name|Expiry'

Result — Names and expiration dates are printed together, so you can spot at-risk certificates.

Key point — For certificates expiring within 30 days, also check the renewal logs.

Things to watch out for

• Even dry-run requests hit Let's Encrypt servers, so excessive repetition can be rate-limited.
• Webroot validation succeeds only if the domain is actually reachable.
• Forcefully reissuing certificates may hit the weekly issuance limit.

Actual execution screen

This is the result of checking certificate expiration dates and the likelihood of automatic renewal success.

!certbot command execution result: certificate list and renewal test

A production server in active use

Source (HTML): https://games.aidebatehub.com/programs/linux/webserver/certbot.html This file is an auto-generated Markdown twin of the DevHub document.