Config seed provider

ConfigSeedProvider returns a static list of seed addresses — from a constructor argument or environment variables. No discovery logic; what you configure is what you get.

import { Cluster, ClusterOptions, ConfigSeedProvider, ConfigSeedProviderOptions } from 'actor-ts';

const configSeedProviderOptions = ConfigSeedProviderOptions.create()
  .withSeeds(['10.0.0.5:2552', '10.0.0.6:2552', '10.0.0.7:2552'])
  .withSystemName('my-app');
const provider = new ConfigSeedProvider(
  configSeedProviderOptions,
);

const seeds = await provider.lookup();
const clusterOptions = ClusterOptions.create()
  .withHost(host)
  .withPort(port)
  .withSeeds(seeds);
await Cluster.join(system, clusterOptions);

The simplest provider for the simplest case.

Configuration

type ConfigSeedProviderOptionsType = {
  seeds:      string[];           // "system@host:port" or "host:port"
  systemName: string;             // default system name for seeds omitting it
};

Two ways to specify:

// Explicit:
const configSeedProviderOptions = ConfigSeedProviderOptions.create()
  .withSeeds(['10.0.0.5:2552', '10.0.0.6:2552'])
  .withSystemName('my-app');
new ConfigSeedProvider(
  configSeedProviderOptions,
);

// From env (CSV):
seedsFromEnv('ACTOR_TS_SEEDS', 'my-app');
// where ACTOR_TS_SEEDS='10.0.0.5:2552,10.0.0.6:2552'

Pick whichever fits your deployment pattern. Env vars are typical for containerized deployments where the list comes from a config map / orchestrator.

When to use it

Three good fits:

1. Docker Compose — known service names + ports; actor-ts-1:2552,actor-ts-2:2552,actor-ts-3:2552 in env.
2. VMs with fixed IPs — three production VMs, each with a stable address.
3. Tests — known peer addresses inline in test setup.

When NOT

Dynamic environments

// K8s pods have ephemeral IPs:
const seedProviderOptions = ConfigSeedProviderOptions.create()
  .withSeeds(['10.244.1.5:2552'])
  .withSystemName('my-app');
new ConfigSeedProvider(seedProviderOptions);   // ✗ breaks on pod recreation

Pod IPs change on every recreation. Use KubernetesApiSeedProvider instead.

Auto-scaling

Fixed seed lists don’t grow when nodes scale up. Once the cluster exists, gossip handles new joiners — but for first contact, only the configured seeds are tried. Aggregate with a DNS or K8s provider for dynamism.

Hostnames vs IPs

const seedProviderOptions = ConfigSeedProviderOptions.create()
  .withSeeds(['my-pod.svc.cluster.local:2552'])
  .withSystemName('my-app');
new ConfigSeedProvider(seedProviderOptions);

Hostnames are resolved at lookup time. If your DNS lags pod startup, lookup fails and Cluster.join retries. Usually works — but IPs are more deterministic when available.

Where to next

• Discovery overview — the bigger picture.
• DNS seed provider — for DNS-based discovery.
• Kubernetes API seed provider — for K8s deployments.
• Aggregate seed provider — combine multiple providers.
• Joining and seeds — how seeds are consumed by the cluster bootstrap.