5 exercises on zero-downtime deployment vocabulary.
0 / 5 completed
1 / 5
What makes a deployment truly zero-downtime?
Zero-downtime: achieved when new instances start and pass health checks before old ones are terminated. Orchestrators handle the gradual traffic shift so no requests are dropped during the transition.
2 / 5
What is a graceful shutdown and why does it matter for zero-downtime?
Graceful shutdown: when a container or process receives SIGTERM, it stops accepting new requests, waits for active ones to complete, then exits. Without it, in-flight requests are abruptly terminated during deployments.
3 / 5
Why are database migrations often the hardest part of zero-downtime deployments?
Backward-compatible migrations: during a rolling deploy, old and new app versions run together. Adding a non-nullable column with no default, or renaming a column, breaks the old version. Migrations should be expand-then-contract: add new, keep old, remove old later.
4 / 5
What is a readiness probe's role in zero-downtime Kubernetes deployments?
Readiness probe: Kubernetes routes traffic only to pods whose readiness probe passes. During rolling updates, new pods receive traffic only once ready, ensuring users are never sent to a pod still warming up.
5 / 5
What is a connection draining (deregistration delay)?
Connection draining: when an instance is deregistered (during a deploy or scale-in), the load balancer stops routing new requests to it but waits a configurable period for existing connections to finish before fully removing it.