Let’s Encrypt, TLS certificates, and HAproxy
I’m evolving. As always, the change is being driven by the most pernicious of motivators: pain. I’ve sold, installed, and upgraded SSL/TLS certificates for years. It’s always been mildly painful: I maintain an offline CA where I generate all the keys and CSR (certificate requests). Then I submit the CSRs to whichever Certificate Authority / Reseller has the best current pricing, get back the new signed certificate from the CA, archive it, and finally install the key, crt, and CA chain file at the destination.
It can be painful and annoying enough that clients regularly hire me to install their certificates for them. To reduce the pain, I’ve encouraged long-duration (3+) year certs. I also have custom scripts tailored to my private CA to reduce the keystrokes. Even so, managing a few dozen certificates was onerous. It didn’t help that every application / daemon (apache, nginx, lighttpd, haproxy, dovecot, qmail, postfix, haraka, etc.) has their own special syntax and sometimes format for configuring the TLS certificates.
Two things happened in 2016 that made TLS management not suck:
- The Internet Security Research Group released Let’s Encrypt(https://letsencrypt.org). It’s a free and highly automated Certificate Authority that validates domain ownership (via DNS or HTTP) and issues certificates in seconds.
- I’ve moved all my web servers behind HAproxy. Now all TLS certs for web servers get deployed to haproxy and the job is done. No messing with lighttpd, apache, or nginx configs. Configure HAproxy get to an A+ at SSLLabs and it covers all the web servers.
Let’s Encrypt provides free signed certificates in just a few seconds, so long as one is willing to invest the time and energy into automating it. I’ve settled on [acme.sh](https://github.com/Neilpang/acme.sh) as my preferred client and once I’ve generated a certificate, it automatically renews and re-deploys it when needed. Just right.
HAproxy now does all the TLS termination, URL routing, scheme upgrades (http -> https), and rewrites. This greatly simplifies the backend web server configs. Need mod_perl, use Apache. Need CGI support, use lighttpd. For everything else I use nginx. Now all of them are simpler to deploy and upgrade.