C# Round Robin Resources

Overview

Round robin assigns each new request to the next resource in a cycle—simple and stateless when backends are homogeneous.

Use it for connection pools, API endpoints, worker queues, or printer pools.

Implementation

Keep an array of resources and an index. On each Next(), atomically increment the index modulo length using Interlocked.Increment. For uneven capacity, use weighted round robin instead.

Wrap failures with try/next so unhealthy nodes are skipped.

When implementing guidance from C# Round Robin Resources, start in a controlled environment that mirrors production versions of operating systems, runtimes, and network policies. Capture a baseline before changes: export configs, snapshot VMs, or tag releases in source control so rollback stays straightforward if behavior regresses.

Document prerequisites, expected outcomes, and verification steps in a short runbook. Automated checks—smoke tests, health endpoints, or query validations—catch regressions early when platforms receive patches. Security belongs in every workflow: apply least privilege, rotate secrets, and review audit logs after deployment.

If results differ across machines, compare environment variables, permission models, time zones, and regional settings. Intermittent issues often trace to caching layers, stale DNS, or duplicated services bound to the same port.

Example

public sealed class RoundRobin {
  private readonly T[] _items;
  private int _index = -1;
  public RoundRobin(IEnumerable items) => _items = items.ToArray();
  public T Next() {
    var i = Interlocked.Increment(ref _index);
    return _items[(i & int.MaxValue) % _items.Length];
  }
}

Tips

• Not optimal when backends differ in power—consider least-connections.
• Combine with health checks.
• Document thread safety for callers.
• Unit test wraparound at int.MaxValue.

• Re-verify after reboots, certificate renewals, or failover exercises.
• Align monitoring and alerts with the failure modes described in this guide.
• Keep vendor documentation links handy for breaking changes between versions.
• Pair automation with a manual spot check during initial production rollout.