Comment by Zealotux
4 years ago
Amusing, I embarrassed myself today as I forgot to renew a client's certificate. This kind of service is unfortunately too expensive for my needs (2 small websites to monitor), wouldn't that be possible to have a small software run on my laptop that checks a list of websites every day for upcoming expiration?
You can do this with the following crappy cronjob (monitoring the machine where your cronjobs run is left as an exercise to the reader / is why you'd want to pay someone to deal with it):
Assuming your system has local mail (via the sendmail command) working, this will send you an email if your certificate expires in the next 864000 seconds = 10 days. If you have an MTA installed but don't use local mail on the machine, you can use the MAILTO feature to send it to your normal email address.
That's pretty useful, thanks.
I can setup a monitor (FOSS) for the computer that is doing the site monitoring, since I only use open source software that I can inspect.
Great one liner to monitor expiring certs, thanks.
Could pipe it to pushback.io too, super easy way to setup push notifications to your phone
Pushback looks fantastic, thank you for sharing.
In addition to monitoring the cert, consider using Let's Encrypt/ACME to auto-rotate certificates.
Unfortunately this also fails in interesting ways...
Just recently, I let one of my certificates expire. The cronjob correctly renewed it, but nginx was not reloaded and kept using the previous certificate. This had never happened before, because I would usually make changes regularly and trigger a reload, which would load the new certificate. Therefore this website had run without issues for 2 years with an incomplete renewal configuration until it finally broke...
Yes, we had lots of issues with nginx serving stale configuration, sometimes even after a reload. I learned to distrust nginx's reload and use two or three nginx servers so I could restart one after updating configs.
dnmin is a small shop that offers it free (I think). I donated the guy $10 for the service a couple of years ago. I got an alert recently, so it works.
Google cloud does checks (of endpoints or tcp connections). I've never been charged as far as I can tell. It sends me a text when my site is down, but it has tons of other notification options