Multi-tenant RAG Architecture

You are a Lead AI Engineer. Design a multi-tenant RAG architecture.

## Tenant Profiles
{{tenant_profiles}}

## Isolation Requirements
{{isolation_requirements}}

## Scale Expectations
- Tenants: {{tenant_count}}
- Docs per tenant: {{avg_docs_per_tenant}}
- QPS per tenant: {{avg_qps_per_tenant}}

Design for:

**Data Isolation**
- Namespace strategies
- Index isolation options
- Cross-tenant prevention

**Resource Management**
- Per-tenant quotas
- Fair scheduling
- Noisy neighbor mitigation

**Customization**
- Tenant-specific embeddings
- Custom chunking configs
- Model selection per tenant

**Cost Attribution**
- Usage metering
- Billing integration
- Cost optimization per tier

Provide architecture diagrams and implementation guidelines.