What causes "unknown caller kind %v" in rancher/rancher?

Verify all Rancher components run the same version (rollout restart the deployment)

unknown caller kind %v

Error message

unknown caller kind %v

What it means

The switch in pkg/capr/configserver/custom.go maps a CallerKind (KindImported, KindCAPINative, KindV2Prov) to an ObjectReference for the requesting machine. Any other value falls through to 'unknown caller kind'. CallerKind originates from the LifecycleContext built in identity.go, so this is an internal invariant break — not user-supplied input.

Source

Thrown at pkg/capr/configserver/custom.go:88

	switch lc.Kind {
	case KindImported:
		return &corev1.ObjectReference{
			APIVersion: v3.SchemeGroupVersion.String(),
			Kind:       "Node",
			Namespace:  machineNamespace,
			Name:       machineName,
		}, nil
	case KindCAPINative, KindV2Prov:
		return &corev1.ObjectReference{
			APIVersion: capi.GroupVersion.String(),
			Kind:       "Machine",
			Namespace:  machineNamespace,
			Name:       machineName,
		}, nil
	}

	return nil, fmt.Errorf("unknown caller kind %v", lc.Kind)
}

func (r *RKE2ConfigServer) findMachineByID(machineID, ns string) (*capi.Machine, error) {
	machines, err := r.machineCache.List(ns, labels.SelectorFromSet(map[string]string{
		capr.MachineIDLabel: machineID,
	}))
	if err != nil {
		return nil, err
	}

	if len(machines) != 1 {
		return nil, fmt.Errorf("unable to find machine %s, found %d machine(s)", machineID, len(machines))
	}

	return machines[0], nil
}

func (r *RKE2ConfigServer) createSecret(namespace, name string, data map[string]interface{}) (*corev1.Secret, error) {

View on GitHub (pinned to 932558d4e6)

Solutions

Verify all Rancher components run the same version (rollout restart the deployment)
If developing: extend the switch at pkg/capr/configserver/custom.go:88 with the new CallerKind case
Report upstream with the lifecycle context details if it reproduces on a stock build

Example fix

// before
switch lc.Kind {
case KindImported:
    ...
case KindCAPINative, KindV2Prov:
    ...
}
return nil, fmt.Errorf("unknown caller kind %v", lc.Kind)

// after (handle new kind explicitly)
switch lc.Kind {
case KindImported:
    ...
case KindCAPINative, KindV2Prov:
    ...
case KindNewProvisioner:
    return &corev1.ObjectReference{ /* ... */ }, nil
}

Defensive patterns

Strategy: type-guard

Type guard

func knownCallerKind(k CallerKind) bool {
    switch k {
    case KindImported, KindCAPINative, KindV2Prov:
        return true
    }
    return false
}

Try / catch

if !knownCallerKind(lc.Kind) {
    return fmt.Errorf("lifecycle context has unsupported kind %q; component version skew?", lc.Kind)
}
// proceed to machineRef()/configserver call

Prevention

Pin all Rancher components to one version and roll them together
When adding a CallerKind, update every switch over it (custom.go, machineRequestSecretName) in the same change
Guard the configserver entry point with a knownCallerKind check so skew fails with a clear message

When it happens

Trigger: A LifecycleContext constructed with an empty or unrecognized Kind: a new CallerKind constant added without extending this switch (version skew between components), or a zero-value context reaching the configserver.

Common situations: Partial Rancher upgrade leaving mixed component versions; local development with an unhandled kind; forks adding a kind but not this case.

Related errors

AI-assisted analysis of rancher/rancher@932558d4e6 (2026-08-16). Data as JSON: /api/errors/349b875903b268dd. Report an issue: GitHub.