Active Active Region Set Up

how does AKS cluster in one region - replicate to other region, from other region to 1st region

AKS clusters themselves do not replicate directly across regions because Kubernetes clusters are designed to be self-contained within a region or cloud zone. Instead, cross-region replication and data synchronization rely on replicating stateful components and data stores.

Here’s how you achieve active-active regional replication between AKS clusters in North India and West India for a banking platform:

1. Cluster Independence

• You have two separate AKS clusters deployed—one in North India, the other in West India.

• Each cluster runs the full set of microservices, Kafka brokers, Istio, and observability stacks independently.

• Kubernetes resources, pods, and configurations are managed independently per cluster.

2. Data Replication Layer

Key data components to replicate:

• Kafka topics

• Databases (Azure SQL, Cosmos DB, etc.)

• Blob Storage (documents, backups)

• Cache layers (Redis, if used)

Kafka Replication

• Use Kafka MirrorMaker 2 or Confluent Replicator for cross-region Kafka topic replication.

• This keeps event streams synchronized across regions.

• Supports active-active messaging where producers and consumers operate in both clusters.

  
  

Database Replication

• Use Azure SQL Geo-Replication or Cosmos DB multi-region writes for transactional data.

• Ensures consistent data state in both regions.

• Databases provide conflict resolution and failover capabilities.

• 
  

Blob Storage & Backups

• Use Geo-Redundant Storage (GRS) in Azure for blobs.

• Automatically replicates objects across regions.

  
  

3. Traffic Routing & Failover

• Use Azure Front Door or Azure Traffic Manager to route users to the nearest healthy region.

• Provides health probes and automatic failover if one region is down.

  
  

4. Service Synchronization

• Configuration data, secrets, and API definitions can be synced using:

  • GitOps workflows (e.g., Flux, ArgoCD) targeting both clusters.

  • Azure Key Vault with multi-region support.

  • Azure App Configuration replicated across regions.

    
    

5. Disaster Recovery & Data Consistency

• Cross-region replication ensures minimal RPO (Recovery Point Objective).

• Active-active ensures near zero RTO (Recovery Time Objective).

• Regular DR drills validate failover and consistency.

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Summary Diagram (Conceptual):

pgsql

[User Requests]

↓

[Azure Front Door / Traffic Manager]

↓ ↓

[AKS Cluster South India] [AKS Cluster West India]

↓ ↓

[Kafka Broker Cluster (Local)] [Kafka Broker Cluster (Local)]

↓ ↓

<-- MirrorMaker2 Replication -->

↓ ↓

[Azure SQL Geo-Replicated DB] <-> [Azure SQL Geo-Replicated DB]

• No direct cluster replication between AKS clusters.

• Replicate data and event streams via Kafka MirrorMaker, DB geo-replication.

• Use global load balancers for routing and failover.

• Sync config and secrets via GitOps and Azure services ( Azure Key Vault with multi-region support. Azure App Configuration replicated across regions.)