How to renew an SSL certificate for VDS?

Question

Digital certificates

There is a VDS server from which there is SSH access.
This VDS has a website. The site had a free SSL certificate that needs to be renewed every 3 months.
How to extend it? In which direction to dig?
There is no ISPmanager on VDS - and no other control panels. Therefore, you can only extend via SSH.

Answer 1

In the absence of panels and the presence of bare SSH, they usually use Cerbot, put it on your server, configure it, and it will automatically update certificates for you.

Answer 2

To begin with, decide what kind of web server you have:
it will show what ports you have listening. You need to find what port 443 is listening on. It will be clear what will need to be restarted and what instructions to follow if necessary.
Next, you need to see if the /etc/letsencrypt folder exists, and if so, check if certbot is installed, and in which version:

which certbot
which certbot-auto

And if not, install according to the instructions for your web server / distribution: https://certbot.eff.org/
If one of them is installed, run:
And see if the certificate is updated, or there will be some kind of error.
If updated, check /etc/cron.d and root's crontab for a task to renew certificates, if not add.
If something goes wrong, accordingly, ask additional already specific questions.