hashicorp/nomad · error

Connect configuration empty for service %s

Error message

Connect configuration empty for service %s

What it means

newConnect builds a Consul AgentServiceConnect from a task's service definition. The 'default' branch of the switch is reached when the service has a non-nil but completely empty (zero-valued) connect block — no sidecar, no gateway, no native config — which is semantically meaningless, so Nomad rejects it.

Source

Thrown at command/agent/consul/connect.go:49

	case nc.IsNative():
		// the service is connect native
		return &api.AgentServiceConnect{Native: true}, nil

	case nc.HasSidecar():
		// must register the sidecar for this service
		if nc.SidecarService.Port == "" {
			nc.SidecarService.Port = fmt.Sprintf("%s-%s", structs.ConnectProxyPrefix, serviceName)
		}
		sidecarReg, err := connectSidecarRegistration(serviceID, info, nc.SidecarService, networks, ports)
		if err != nil {
			return nil, err
		}
		return &api.AgentServiceConnect{SidecarService: sidecarReg}, nil

	default:
		// a non-nil but empty connect block makes no sense
		return nil, fmt.Errorf("Connect configuration empty for service %s", serviceName)
	}
}

// newConnectGateway creates a new Consul AgentServiceConnectProxyConfig struct based on
// a Nomad Connect struct. If the Nomad Connect struct does not contain a gateway, nil
// will be returned as this service is not a gateway.
func newConnectGateway(connect *structs.ConsulConnect) *api.AgentServiceConnectProxyConfig {
	if !connect.IsGateway() {
		return nil
	}

	var envoyConfig map[string]any

	// Populate the envoy configuration from the gateway.proxy block, if
	// such configuration is provided.
	if proxy := connect.Gateway.Proxy; proxy != nil {
		envoyConfig = make(map[string]any)

View on GitHub (pinned to 482b49bf1a)

Solutions

1. Populate the connect block: add a sidecar_service block, a gateway (ingress/terminating/mesh), or set native = true.
2. Remove the connect block entirely if Connect is not intended for this service.
3. Validate the job with nomad job validate before submission to catch the empty block.

Example fix

// before
service {
  name = "web"
  connect {}
}
// after
service {
  name = "web"
  connect {
    sidecar_service {}
  }
}

func connectBlockEmpty(c *structs.ConsulConnect) bool {
  return c != nil && c.SidecarService == nil && c.Gateway == nil && !c.Native
}
if connectBlockEmpty(svc.Connect) {
  return fmt.Errorf("service %s: connect block is empty", svc.Name)
}

When it happens

Trigger: Declaring a connect stanza in a Nomad service that sets nothing (e.g. connect {} with no sidecar_service, gateway, or native), causing newConnect to fall through to the default case.

Common situations: Job authors write an empty connect block intending to enable sidecars but forget to configure the sidecar_service or gateway; jobs copied from examples where the meaningful fields were stripped.

Related errors

• consul address must be set on nomad client
• error creating bootstrap configuration for Connect proxy sid
• Service with provider nomad cannot include Connect blocks
• missing %q
• Connect only supported with exactly 1 network (found %d)

AI-assisted analysis of hashicorp/nomad@482b49bf1a (2026-09-04). Data as JSON: /api/errors/06b1a90857c7752a. Report an issue: GitHub.