Hi @yeah-nothing,
If you didn't create an entry in your cron... no, certbot-auto doesn't renew the certificate automatically.
Yes, it expires in 17 days.
CRT ID DOMAIN (CN) VALID FROM VALID TO EXPIRES IN SANs
100473088 yeah-nothing.com 2017-Mar-08 20:55 CET 2017-Jun-06 21:55 CEST 17 days www.yeah-nothing.com
yeah-nothing.com
Add a job to root's crontab, something like this:
# crontab -e
And now add a line like:
17 */12 * * * /path/to/certbot-auto renew --quiet
This cron job will run twice a day, it will check if your will expire in less than 30 days, it it doesn' it will do nothing, if it will expire in less than 30 days it will try to issue a new cert using the same paramaters as the first time you issued your cert.
Keep in mind that by default it won't reload your web server to use the new certificate but you can add an option to certbot-auto renew to do it for you every time the cert is renewed.
Take a look to this post Newbie needs help with DuckDNS + LE + Ubuntu - #6 by sahsanu (in the post I use examples with letsencrypt-auto, in your case you should use certbot-auto and the right path to it, the same for the service you need to reload, use the right command to rload/restart the services using the certificate).
Good luck,
sahsanu