Best Physical Architecture - Optimizely CMS 12

Exam Area: Area 2 – Installation, Operation & Configuration (20%) Reference: https://docs.developers.optimizely.com/content-management-system/docs/deploying-to-production

---

1. Guiding Principle

Optimizely CMS is a distributed, stateless application. Multiple web servers can serve the same site, provided they share:

1. SQL Server database (content + configuration)
2. Blob storage (media files)
3. Distributed cache (Redis — cache coherency)
4. Event messaging (Azure Service Bus — cache invalidation)

---

2. Minimum Production Setup

Internet
    │
    ▼
[ Load Balancer / Azure Front Door ]
    │
    ├──▶ [ Web Server 1 ] (ASP.NET Core, Kestrel/IIS)
    └──▶ [ Web Server 2 ] (ASP.NET Core, Kestrel/IIS)
              │
              ├──▶ [ Azure SQL / SQL Server ] (shared)
              ├──▶ [ Azure Blob Storage ]     (shared media)
              ├──▶ [ Azure Redis Cache ]      (shared L2 cache)
              └──▶ [ Azure Service Bus ]      (cache invalidation events)

---

3. Required Shared Components

---

4. Development / Local Setup

Developer Machine:
  ├── IIS / IIS Express / Kestrel
  ├── SQL Server LocalDB or SQL Express
  ├── Local file system (no blob storage needed)
  ├── In-memory cache (no Redis needed)
  └── No Service Bus (single process, no cache sync needed)

---

5. DXP (Azure Paas) Architecture

The Optimizely Digital Experience Platform (DXP) provides a fully managed Azure infrastructure:

DXP Environments:
┌─────────────────────────────────────────────────────────┐
│ Integration (DEV)                                        │
│   App Service: 1 instance (B2/B3)                       │
├─────────────────────────────────────────────────────────┤
│ Preproduction (STAGING)                                  │
│   App Service: 1-2 instances                            │
├─────────────────────────────────────────────────────────┤
│ Production                                               │
│   App Service Plan: 2+ instances (auto-scale)           │
│   + Azure SQL Managed Instance                          │
│   + Azure Blob Storage (private endpoint)               │
│   + Azure Redis Cache (private endpoint)                │
│   + Azure CDN (Akamai/Azure Front Door)                 │
│   + Azure Service Bus                                    │
│   + Azure Application Insights                          │
└─────────────────────────────────────────────────────────┘

---

6. Configuration for Distributed Cache (Redis)

// Program.cs — configure Redis as distributed cache
builder.Services.AddStackExchangeRedisCache(options =>
{
    options.Configuration = configuration["Redis:ConnectionString"];
    options.InstanceName  = "MyProject:";
});

// CMS will automatically use the registered IDistributedCache

---

7. Configuration for Azure Service Bus (Events)

// Program.cs — use Azure Service Bus for CMS events
builder.Services.Configure<ServiceBusOptions>(options =>
{
    options.ConnectionString = configuration["AzureServiceBus:ConnectionString"];
    options.TopicName        = "episerver-events";
});

builder.Services.AddCmsAzureServiceBusEventProvider();

---

8. Blob Storage Configuration

// Program.cs — Azure Blob provider
builder.Services.AddAzureBlobProvider(options =>
{
    options.ConnectionString = configuration["AzureBlobStorage:ConnectionString"];
    options.ContainerName    = "mysitemedia";
});

---

9. Why Shared State Matters

---

10. Scheduled Jobs in Multi-Server

• CMS uses the SQL database to coordinate scheduled job execution
• Only one server runs each job at a time (leader election via DB)
• Other servers skip execution if the job is already running

---

Review Questions

1. What 4 components must be shared between CMS web servers? (SQL Server, Blob Storage, Redis Cache, Service Bus)
2. Why is Azure Service Bus needed in a multi-server setup? (Cache invalidation — when one server publishes content, all others are notified to flush their cache)
3. Is Redis required for a single-server setup? (No — in-memory cache is sufficient)
4. What DXP environment should be used for final testing before production? (Preproduction)
5. How does CMS prevent duplicate scheduled job execution on multiple servers? (SQL-based leader election — only one server runs the job)