Akka.Discovery.Redis

Akka.Discovery.Redis

Redis-based service discovery for Akka.NET. Each node registers itself in Redis under a time-to-live (TTL) key and refreshes it on a heartbeat; peers discover one another by scanning those keys. It is a lightweight alternative to Akka.Discovery.Azure for cluster member discovery, well suited to .NET Aspire local development and any environment that already runs Redis.

Dead nodes are removed automatically by Redis key expiry — there is no separate pruning process — and stale (but not-yet-expired) nodes are filtered out of lookups via a configurable stale-ttl-threshold.

Installation

dotnet add package Akka.Discovery.Redis

Usage with Akka.Hosting

using Akka.Discovery.Redis;
using Akka.Hosting;

builder.Services.AddAkka("MySystem", akka =>
{
    akka
        .WithClustering()
        .WithClusterBootstrap(options =>
        {
            options.ContactPointDiscovery.ServiceName = "my-service";
            options.ContactPointDiscovery.RequiredContactPointsNr = 3;
        }, autoStart: true)
        .WithRedisDiscovery("localhost:6379");
});

WithRedisDiscovery only registers the discovery plugin; pair it with WithClusterBootstrap for automated cluster formation.

Options

akka.WithRedisDiscovery(options =>
{
    options.ConnectionString = "localhost:6379";
    options.ServiceName = "my-service";
    options.StaleTtlThreshold = TimeSpan.FromSeconds(90);
    options.OperationTimeout = TimeSpan.FromSeconds(10);
});

Configuration

The plugin reads from akka.discovery.redis. See reference.conf for the full set of keys and their defaults, including ttl, ttl-heartbeat-interval, stale-ttl-threshold, operation-timeout, retry-backoff, max-retry-backoff, and read-only.

Resilience

• The Redis connection is established lazily inside the discovery guardian actor, so an unreachable Redis at startup never blocks or fails ActorSystem startup — the plugin retries with exponential backoff and recovers once Redis is reachable.
• Every Redis operation is bounded by operation-timeout.
• The heartbeat refreshes each node's TTL key; if a node stops heartbeating, Redis expires the key and the node drops out of discovery.

License

Apache-2.0