Zero-downtime deployment ensures that your application remains available to users while upgrading from v0.0.1 to v0.0.2. Below are the most common strategies to achieve this:
- Two Environments: Maintain two identical environments: "Blue" (live, v0.0.1) and "Green" (new, v0.0.2).
- Deploy & Test: Deploy v0.0.2 to "Green" and run all necessary tests.
- Switch Traffic: Update the load balancer to route all traffic to "Green" once ready.
- Rollback: If issues arise, revert traffic to "Blue".
- Decommission: Shut down or repurpose "Blue" after successful migration.
Benefits:
- Simple rollback
- Minimal risk
- Easy to understand and implement
- Deploy Canary: Release v0.0.2 to a small subset of users while v0.0.1 remains live.
- Partial Traffic: Configure the load balancer to send 5-10% of traffic to v0.0.2.
- Monitor: Observe performance, error rates, and user feedback.
- Gradual Rollout: Increase traffic to v0.0.2 incrementally until it serves all users.
- Decommission: Remove v0.0.1 after full rollout.
Benefits:
- Limits risk to a small user group
- Real-world testing before full release
- Instance-by-Instance: Remove one server running v0.0.1 from rotation.
- Update: Upgrade it to v0.0.2 and re-add to the load balancer.
- Repeat: Continue until all servers run v0.0.2.
Benefits:
- No downtime
- Continuous availability
All these strategies allow for seamless upgrades with no downtime, ensuring user experience is uninterrupted. Choose the method that best fits your infrastructure and risk tolerance.