derailed/k9s · error

invalid benchmark host %q

Error message

invalid benchmark host %q

What it means

Service.runBenchmark (internal/view/svc.go:154) requires a non-empty cfg.HTTP.Host from the BenchConfig (k9s config `k9s.bench` section) before building the benchmark URL. An empty host means the benchmark feature was invoked without any bench configuration, so there is no target to load-test.

Source

Thrown at internal/view/svc.go:154

	}
	port, err := s.getExternalPort(svc)
	if err != nil {
		s.App().Flash().Err(err)
		return nil
	}
	if err := s.runBenchmark(port, &cfg); err != nil {
		s.App().Flash().Errf("Benchmark failed %v", err)
		s.App().ClearStatus(false)
		s.bench = nil
	}

	return nil
}

// BOZO!! Refactor used by forwards.
func (s *Service) runBenchmark(port string, cfg *config.BenchConfig) error {
	if cfg.HTTP.Host == "" {
		return fmt.Errorf("invalid benchmark host %q", cfg.HTTP.Host)
	}

	var err error
	base := cfg.HTTP.Host
	if !strings.Contains(base, ":") {
		base += ":" + port + cfg.HTTP.Path
	} else {
		base += cfg.HTTP.Path
	}
	if strings.Index(base, "http") != 0 {
		base = "http://" + base
	}

	if s.bench, err = perf.NewBenchmark(base, s.App().version, cfg); err != nil {
		return err
	}

	s.App().Status(model.FlashWarn, "Benchmark in progress...")

View on GitHub (pinned to 2d3ccc6ba2)

Solutions

1. Add a bench config with an explicit host to ~/.config/k9s/config.yml (see exampleFix), then restart k9s
2. Verify the active k9s context actually matches the bench section you edited
3. Validate config syntax after editing (yaml indentation) — a malformed config silently drops the bench stanza
4. Alternatively run a load tool directly (hey/wrk) against the service DNS

Example fix

# before: no bench section -> invalid benchmark host ""
k9s:
  readOnly: false

# after
k9s:
  bench:
    default:
      bench:
        - name: bench
          host: http://my-svc.my-ns.svc.cluster.local:8080
          suffix: /api/health

// validate bench config before invoking the benchmark
if cfg == nil || strings.TrimSpace(cfg.HTTP.Host) == "" {
    return fmt.Errorf("no bench host configured; add k9s.bench.<context>.bench[].host to config.yml")
}

When it happens

Trigger: Triggering the service benchmark (shift+b on a service/port-forward) when the config's bench entry for that context has no http.host set — e.g. the default bench entry is missing entirely or exists only with cooldown/threads.

Common situations: Fresh k9s installs without a bench stanza in ~/.config/k9s/config.yml; context-specific bench overrides that omit host; users assuming k9s derives the host from the service automatically.

Related errors

• you must select a reachable service
• k9s config file %q load failed: %w
• main config.yaml load failed: %w
• duplicate input name %q
• default value %q for bool input %q must be "true" or "false"

AI-assisted analysis of derailed/k9s@2d3ccc6ba2 (2026-08-15). Data as JSON: /api/errors/3b28ed02a537e0c7. Report an issue: GitHub.