kubernetes/kops · critical

no instance group defined in nodeup config

Error message

no instance group defined in nodeup config

What it means

NodeUpCommand.Run needs to load the NodeupConfig either from a config-server response (nodeConfig) or by joining an instance group name onto ConfigBase. This error means neither branch matched: bootConfig had no ConfigServer servers, no InstanceGroupName, so nodeup cannot know which instance group's nodeupconfig.yaml to fetch. Run aborts immediately at the switch's default case.

Source

Thrown at upup/pkg/fi/nodeup/command.go:158

		nodeupConfigHash = sha256.Sum256([]byte(nodeConfig.NodeupConfig))
		if nodeupConfig.CAs == nil {
			nodeupConfig.CAs = make(map[string]string)
		}
		nodeupConfig.CAs[fi.CertificateIDCA] = bootConfig.ConfigServer.CACertificates
	case bootConfig.InstanceGroupName != "":
		nodeupConfigLocation := configBase.Join("igconfig", bootConfig.InstanceGroupRole.ToLowerString(), bootConfig.InstanceGroupName, "nodeupconfig.yaml")

		b, err := nodeupConfigLocation.ReadFile(ctx)
		if err != nil {
			return fmt.Errorf("error loading NodeupConfig %q: %v", nodeupConfigLocation, err)
		}

		if err = utils.YamlUnmarshal(b, &nodeupConfig); err != nil {
			return fmt.Errorf("error parsing NodeupConfig %q: %v", nodeupConfigLocation, err)
		}
		nodeupConfigHash = sha256.Sum256(b)
	default:
		return fmt.Errorf("no instance group defined in nodeup config")
	}

	if bootConfig.NodeupConfigHash != "" {
		if want, got := bootConfig.NodeupConfigHash, base64.StdEncoding.EncodeToString(nodeupConfigHash[:]); got != want {
			return fmt.Errorf("nodeup config hash mismatch (was %q, expected %q)", got, want)
		}
	}

	err = evaluateSpec(&nodeupConfig, bootConfig.CloudProvider, region)
	if err != nil {
		return err
	}

	architecture, err := architectures.FindArchitecture()
	if err != nil {
		return fmt.Errorf("error determining OS architecture: %v", err)
	}

View on GitHub (pinned to 4c8573c808)

Solutions

1. Set InstanceGroupName in the BootConfig handed to NodeUpCommand (or in the boot config YAML at ConfigLocation) to the node's instance group, e.g. "nodes" or "master-us-east-1a".
2. Alternatively configure ConfigServer (bootConfig.ConfigServer.Servers) so nodeup fetches its config from the kOps config server instead of VFS.
3. Inspect the node's boot configuration source (userdata / nodeup.conf) to find why the field is missing — often a broken templating step — and re-render and re-provision the node.
4. Ensure 'kops update cluster' ran so the state store and node userdata were generated by the same kOps version.

Example fix

// before (boot config yaml)
configBase: s3://bucket/cluster.k8s.local
// after
configBase: s3://bucket/cluster.k8s.local
instanceGroupName: nodes

// Ensure the boot config carries either a config server or an instance group
if bootConfig.ConfigServer == nil || len(bootConfig.ConfigServer.Servers) == 0 {
    if bootConfig.InstanceGroupName == "" {
        return fmt.Errorf("boot config must set ConfigServer or InstanceGroupName")
    }
}

err := cmd.Run(out)
if err != nil && strings.Contains(err.Error(), "no instance group defined") {
    // re-render userdata/boot config with InstanceGroupName set
}

When it happens

Trigger: Calling NodeUpCommand.Run() with a BootConfig where ConfigServer is nil/empty AND InstanceGroupName == "" — e.g. the nodeup boot config file passed via ConfigLocation (or nodeup.conf kernel args) omits both configServer and InstanceGroupName.

Common situations: Corrupted or truncated /etc/kubernetes/nodeup.conf or userdata-generated boot config on the node; templating in cloud-init/userdata failed to render InstanceGroupName; hand-built nodeup invocations in tests or custom installers that forgot to set the field.

Understand the failure class

Background: "is required", "must be set", "missing required field": configuration validation errors across open-source libraries — this error's family across 36 libraries.

Related errors

• SecretStore not set
• building nodeConfig for instanceGroup: %w
• unsupported cloud provider for authenticator %q
• no keypairID for %q
• KubeProxy not configured

AI-assisted analysis of kubernetes/kops@4c8573c808 (2026-09-05). Data as JSON: /api/errors/4c6927c2dcea0e22. Report an issue: GitHub.