Scaling Workers

Airtruct's worker pool architecture makes horizontal scaling straightforward. This guide covers how to add workers and distribute workload.

Adding Workers

Each worker is an independent process that registers with the coordinator. To add a worker:

./airtruct -role worker -grpc-port 50002 -discovery-uri localhost:50000

• Use a unique -grpc-port for each worker on the same host.
• Set -discovery-uri to the coordinator's gRPC address (default localhost:50000).

Workers automatically register on startup and begin accepting stream assignments.

Multi-Host Deployment

Run workers on separate machines by pointing them to the coordinator's address:

# On machine B
./airtruct -role worker -grpc-port 50001 -discovery-uri coordinator-host:50000

The coordinator tracks all workers and distributes streams across them.

Worker Health

Workers send periodic heartbeats to the coordinator. If a worker stops sending heartbeats, the coordinator marks it as unhealthy and can reassign its streams.

Scaling Strategies

Vertical Scaling

Increase the resources (CPU, memory) of individual worker machines. Airtruct is Go-native and efficient with resources.

Horizontal Scaling

Add more worker processes. This is the recommended approach for handling increased workload:

• Each worker can run multiple streams.
• The coordinator balances stream assignments across available workers.
• Workers can be added or removed without downtime.

Kubernetes

Deploy workers as a StatefulSet rather than a Deployment. StatefulSets give each pod a stable, predictable hostname (e.g., airtruct-worker-0, airtruct-worker-1). With a Deployment, pods get random names on every restart, which causes stale worker registrations to pile up in the coordinator.

kubectl scale statefulset airtruct-worker --replicas=5

Each pod registers as an independent worker with the coordinator using its stable hostname.