Dual Mode¶

The dual mode (DUAL_MODE) connects to multiple Aerospike clusters and routes reads/writes based on a configurable routing strategy.

Use Cases¶

• Live migration: Gradually shift traffic from one cluster to another
• Disaster recovery: Route reads to a replica cluster when primary is degraded
• Geographic routing: Route to the nearest cluster

How It Works¶

sequenceDiagram
    participant App as Application
    participant DualClient as DualModeAerospikeClient
    participant Resolver as DualModeASClientResolver
    participant ClusterA as Cluster A
    participant ClusterB as Cluster B

    App->>DualClient: get(key)
    DualClient->>Resolver: getReadClient()
    Resolver-->>DualClient: Cluster A client
    DualClient->>ClusterA: get(key)
    ClusterA-->>App: record

    App->>DualClient: put(key, bins)
    DualClient->>Resolver: getWriteClient()
    Resolver-->>DualClient: Cluster B client
    DualClient->>ClusterB: put(key, bins)
    ClusterB-->>App: success

Configuration¶

aerospike:
  modeOfOperationType: DUAL_MODE
  aerospikeConfiguration:
    - id: "cluster-a"
      hosts:
        - host: "cluster-a.example.com"
          port: 3000
      healthcheckEnabled: true
    - id: "cluster-b"
      hosts:
        - host: "cluster-b.example.com"
          port: 3000
      healthcheckEnabled: true
  asReadWriteConfig:
    readClusterId: "cluster-a"
    writeClusterId: "cluster-b"

Dynamic Routing¶

Override refreshDualModeASReadWriteConfig() to dynamically change which cluster handles reads vs writes at runtime:

@Override
protected Supplier<DualModeASReadWriteConfig> refreshDualModeASReadWriteConfig(
        MyAppConfiguration config) {
    return () -> {
        // Fetch from config service, feature flag, etc.
        return DualModeASReadWriteConfig.builder()
            .readClusterId("cluster-b")
            .writeClusterId("cluster-b")
            .build();
    };
}

Validation¶

• All cluster IDs must be unique
• readClusterId and writeClusterId must reference valid cluster IDs from the configuration
• Each cluster gets its own health check: aerospike-bundle-<id>

DualModeASClientResolver¶

This is a Dropwizard Managed object that periodically refreshes the read/write routing configuration. It maintains a map of cluster ID to IAerospikeClient and resolves the appropriate client for each operation type.