Tools: Automating TLS Certificate Lifecycle With Let's Encrypt And Acme
Posted on Feb 13
• Originally published at timderzhavets.com
Your production site just went down at 3 AM because someone forgot to renew a certificate. Again. The manual renewal process that worked fine for two servers has become a liability now that you're managing fifty. Every quarter, the same ritual: calendar reminders, SSH sessions, certbot commands, nginx reloads, and the lingering anxiety that you missed one. Until you did.
Certificate expiration is the silent killer of uptime. It doesn't trigger your APM alerts. Load balancers report the backend as healthy right up until browsers start throwing ERR_CERT_DATE_INVALID. By the time your on-call engineer figures out what's happening, customers have already screenshot the security warning and posted it to Twitter.
The fundamental issue isn't negligence—it's that manual processes decay. The engineer who set up the original certificates left the company. The renewal documentation lives in a Confluence page that hasn't been updated since 2019. The cron job that was supposed to handle this silently failed six months ago because someone rotated the service account credentials.
Let's Encrypt changed the economics of TLS certificates, but their 90-day validity window was a deliberate design choice, not a limitation. Short-lived certificates force automation. They're worthless to attackers who compromise your private key three months later. But that 90-day window also means you're running a renewal process four times more often than traditional certificates—and four times more opportunities for failure.
The ACME protocol that powers Let's Encrypt wasn't just built for free certificates. It was built for machines to manage certificates without human intervention. The question isn't whether to automate certificate management—it's how to build automation that survives infrastructure changes, team turnover, and the inevitable edge cases that break naive implementations.
TLS certificate management seems straightforward until it isn't. A single certificate renewal takes minutes. Managing hundreds of certificates across distributed services while maintaining zero downtime requires a fundamentally different approach.
Let's Encrypt certificates expire every 90 days by design. This short validity period limits the damage from compromised certificates and encourages automation. However, it creates a relentless operational cadence that exposes weaknesses in manual processes.
Consider a tea
Source: Dev.to
