Renewal is automatic from when you issued the certificate with the --post-hook, you don’t need to do anything. Since you installed Certbot from repositories, a cronjob already exists on your system.
Because it is pointing to the same root folder.
It just isn't using varnish though now.
The proxy pass is to force it back to varnish which will then bring it back to port 8080.
And provide all the varnishy things it provides.
That would try to renew and when it does renew would execute whatever came after post-hook.
which is what we want in the cron job
Attempt to renew and when it does renew then restart apache.
first test these two and then we use whichever works from command line: /usr/bin/certbot renew -q --deploy-hook 'service apache restart' /usr/bin/certbot renew -q --post-hook 'service apache restart'
Assuming which certbot
shows it at /usr/bin/
Feel free to change the "service apache restart" to however you restart your apache...
The difference between deploy and post are: deploy only kicks off when the cert is actually "deployed" (meaning renewed) post will kick off immediately after every attempt (even if NOT renewed)