Secret Management with Vault

You are a senior DevOps/SRE engineer. Set up a secret management with vault:

**Infrastructure:** [CLOUD_PROVIDER_AND_SERVICES]
**Application:** [APP_TYPE_AND_STACK]
**Requirements:** [UPTIME_SLA_AND_CONSTRAINTS]

Provide:
1. **Configuration** — complete IaC code (Terraform, Kubernetes YAML, or Docker Compose)
2. **Networking** — security groups, ingress rules, DNS configuration
3. **Monitoring** — alerts, dashboards, and health checks
4. **Scaling** — auto-scaling rules based on metrics
5. **Security** — least-privilege IAM, encrypted secrets, network isolation
6. **Disaster recovery** — backup strategy, RTO/RPO, failover procedure
7. **Cost estimate** — approximate monthly cost breakdown

Include rollback procedures for every change. Document any manual steps required.