[DOCS] Create Low-Level Design (LLD) document based on current repo and documentation

[kristopherjturner]

Summary

Create a comprehensive Low-Level Design (LLD) document for the Azure Local Cloud reference solution. The LLD provides the detailed technical specification of the solution — specific configurations, IP schemes, naming conventions, component settings, and validation procedures — complementing the High-Level Design (HLD).

The LLD should be based on the current state of the codebase, variable templates, and documentation and placed in the docs/design/ section of the docs site.

Dependency: This issue depends on the HLD being complete or in progress (see HLD issue). The LLD references and extends the architectural decisions made in the HLD.

Audience

• Implementation engineers performing the deployment
• Senior engineers and architects reviewing technical specifications
• Operations teams who need detailed reference during day-2 activities

Document Structure

1. Document Scope and Purpose

• Relationship to the HLD
• How to use this document alongside the Implementation Guide

2. Environment Specifications

Based on the IIC (Contoso) reference environment from the variable templates:

Azure Environment

Attribute	Value
Subscription	(from variables.example.yml)
Management Group	Reference a master-registry.yaml entry
Primary Region	eastus (reference default)
Resource Group Pattern	rg-iic-<purpose>-<##>

On-Premises Hardware Specifications

• Node count, CPU/memory/storage baseline for the reference design
• Dell PowerEdge configuration reference (from appendix-i-dell-config.mdx)
• BOSS card / NVMe / HDD tiering specification

Network Design

Network	CIDR	Purpose
Management	10.0.0.0/24	Node management NICs
Compute	10.0.2.0/24	Workload (VM) traffic
Storage	(from RDMA network design)	RDMA storage traffic
BMC/OOB	(iDRAC)	Out-of-band management

Full network design: VLANs, IP assignments for each node, switch port mapping.

3. Identity and Access Design

• AD domain structure (OU hierarchy from scripts/deploy/02-azure-foundation/)
• Service accounts (naming pattern: svc.iic.<purpose>)
• Arc service principal setup
• Key Vault secrets layout
• RBAC role assignments per phase

4. Storage Design

• S2D pool configuration (cache tier, capacity tier)
• Volume layout: CSV volumes, FSLogix shares
• Storage fault domain design
• Resync, quorum, and HA configuration

5. Networking Detail

• Network ATC intent configuration
• RDMA adapter settings (SR-IOV, MTU, QoS)
• Logical network definitions for Arc VMs
• SDN configuration (if applicable)
• DNS zones, records, and forwarder configuration
• DHCP scope design

6. Azure Services Configuration

Service	Key Settings
Log Analytics Workspace	Retention, solutions enabled
Azure Monitor	Alert rules, action groups
Azure Backup	Vault, policy — VMs and SOFS
Azure Site Recovery	Replica region, RPO/RTO targets
Defender for Cloud	Security standard, MCSB baseline
Update Manager	Maintenance window, ring strategy
Key Vault	Access policies/RBAC, secret naming

7. Variable Mapping

• Summary of the key variables from variables.example.yml and master-registry.yaml
• Which variables must be customized per deployment
• Variables with organization-wide defaults

8. Script-to-Task Mapping

Reference table mapping each implementation guide task to its script file:

Phase	Task	Script
Phase 0	CI/CD Bootstrap	scripts/deploy/01-cicd-infra/...
Phase 1	Management Groups	scripts/deploy/02-azure-foundation/...
...	...	...

9. Validation and Acceptance Criteria

• Per-phase validation checklist (reference the implementation guide appendix)
• Pass/fail criteria for each phase
• Sign-off requirements

10. Configuration Templates Reference

• Reference appendix-e-config-templates.mdx for config file templates
• Variable file template location: config/variables/variables.example.yml
• Script index: appendix-d-script-index.mdx

Placement

Create the document at: docs/design/low-level-design.mdx

The docs/design/ section already exists in the site.

Acceptance Criteria

• LLD document created at docs/design/low-level-design.mdx
• Network design table completed (based on variables.example.yml default values)
• Storage design section completed (based on S2D deployment scripts)
• Azure services configuration table completed (based on phase scripts and variable registry)
• Script-to-task mapping table references accurate script paths
• Variable mapping table covers the most critical variables from master-registry.yaml
• Document is self-consistent with the HLD and implementation guide
• npm run build passes with no broken links

References

• config/variables/variables.example.yml — baseline variable values to document
• config/variables/master-registry.yaml — full variable registry
• docs/design/ — section where this document belongs
• docs/implementation/04-variable-management-standard.mdx — variable management context
• docs/implementation/appendices/appendix-d-script-index.mdx — script index
• docs/implementation/appendices/appendix-e-config-templates.mdx — config templates
• docs/implementation/appendices/appendix-f-network-validation.mdx — network validation
• HLD issue (create this after or in parallel with HLD)

[kristopherjturner]

Tracked in Azure DevOps as User Story #42 — https://dev.azure.com/hybridcloudsolutions/AzureLocal%20Community%20Site/_workitems/edit/42