Prompt

Design zero-downtime deployment strategy.

<current_deployment>
{existing deployment process}
</current_deployment>

<application_architecture>
{stateful/stateless components}
</application_architecture>

<traffic_patterns>
{peak times and geographic distribution}
</traffic_patterns>

Design:
1. Blue-green vs canary approach
2. Database migration strategy
3. Session handling
4. Traffic switching
5. Rollback procedures
6. Health checking