kubernetes/kops · error

error marshaling authentication config to yaml: %v

Error message

error marshaling authentication config to yaml: %v

What it means

writeAuthenticationConfig wraps kops.ToRawYaml failure while serializing the webhook authentication kubeconfig for the kube-apiserver static pod. It fires when the generated config struct (clusters/users/contexts for the webhook) cannot be marshaled to YAML — practically only on unexpected struct/JSON-tag issues — and aborts adding the authentication config manifest.

Source

Thrown at nodeup/pkg/model/kube_apiserver.go:334

			Kind:       "Config",
			ApiVersion: "v1",
		}
		config.Clusters = append(config.Clusters, &kubeconfig.KubectlClusterWithName{
			Name:    "webhook",
			Cluster: cluster,
		})
		config.Users = append(config.Users, &kubeconfig.KubectlUserWithName{
			Name: "kube-apiserver",
		})
		config.CurrentContext = "webhook"
		config.Contexts = append(config.Contexts, &kubeconfig.KubectlContextWithName{
			Name:    "webhook",
			Context: context,
		})

		manifest, err := kops.ToRawYaml(config)
		if err != nil {
			return fmt.Errorf("error marshaling authentication config to yaml: %v", err)
		}

		c.AddTask(&nodetasks.File{
			Path:     PathAuthnConfig,
			Contents: fi.NewBytesResource(manifest),
			Type:     nodetasks.FileType_File,
		})

		return nil
	}

	if b.NodeupConfig.APIServerConfig.Authentication.AWS != nil {
		id := "aws-iam-authenticator"
		kubeAPIServer.AuthenticationTokenWebhookConfigFile = new(PathAuthnConfig)

		{
			cluster := kubeconfig.KubectlCluster{
				Server:                   "https://127.0.0.1:21362/authenticate",

View on GitHub (pinned to 4c8573c808)

Solutions

1. Check the authentication webhook settings in the spec
2. Report encoding failures to kOps maintainers
3. Re-run nodeup

When it happens

Trigger: Thrown at nodeup/pkg/model/kube_apiserver.go:334 when the library encounters an invalid state.

Common situations: See trigger scenarios.

Understand the failure class

• Authentication and authorization failures — expired tokens, bad credentials, and missing scopes.

AI-assisted analysis of kubernetes/kops@4c8573c808 (2026-09-05). Data as JSON: /api/errors/d24335f677adea92. Report an issue: GitHub.