A production order-processing service has 99.9% uptime SLA, runs as a single Docker container with `restart: always`, and the team is confident because 'it auto-restarts on crash'

Identify the gaps in this design relative to a true HA architecture and propose a concrete remediation plan. Expected reasoning: identify that a single container is a host-level single point of failure regardless of its restart policy (a host failure, kernel panic, or maintenance reboot causes real downtime with no failover target); recommend running at least 2-3 replicas across separate hosts/AZs behind a load balancer with active health checks; check whether the service is stateless (if it holds local session state, that must be externalized first, e.g., to Redis, before horizontal scaling i