Health Checks

A health check tells Zenavo when a new instance is ready to receive traffic, which is what makes rollouts zero-downtime.

• Default: a service with a TCP or HTTP port is checked by opening a TCP connection to its first port every 10 seconds, with a 5-second timeout and 3 failures allowed.
• Custom: a command run inside the container, such as pg_isready -U postgres. Databases added from the console and many templates include one.
• No ports: workers without ports have no check; they count as ready once started.

Crash limit

If a service keeps crashing, Zenavo can suspend it after a number of restarts (its crash limit) instead of restarting it forever. The service then shows a notice; check its logs, then resume it or deploy a fix.