Nagios, in combination with with check_mk 'raw edition' (https://mathias-kettner.com/editions.html https://mathias-kettner.com/editions.html). The Nagios config

Nagios, in combination with with check_mk 'raw edition' (https://mathias-kettner.com/editions.html https://mathias-kettner.com/editions.html). The Nagios configuration is automatically generated via Puppet resource collection. SSL certificate expiry is easily checked with a nagios check (use the -C flag on check_http). If you use Letsencrypt with a client like acmetool (https://github.com/hlandau/acme https://github.com/hlandau/acme) your certs will never expire. Of course the nagios check is still necessary to ensure acmetool keeps doing its job! Domain name expiry checking could also be a nagios job, or alternatively you could write a small script that checks whois output and execute it regularly with cron. Configuring your registrar for auto-renewal helps avoid a certain class of errors ("I forgot to renew!") but not others ("my credit card expired and the e-mail notifications from my registrar didn't reach me").