Support clusters with no node groups

pkg/lib/configreader/reader.go

@@ -94,7 +94,7 @@ type StructListValidation struct {
 	StructValidation      *StructValidation
 	Required              bool
 	AllowExplicitNull     bool
-	TreatNullAsEmpty      bool // If explicit null or if it's top level and the file is empty, treat as empty map
+	TreatNullAsEmpty      bool // If explicit null or if it's top level and the file is empty, treat as empty list
 	MinLength             int
 	MaxLength             int
 	InvalidLengths        []int

pkg/operator/resources/errors.go

@@ -44,6 +44,7 @@ const (
 	ErrRealtimeAPIUsedByTrafficSplitter = "resources.realtime_api_used_by_traffic_splitter"
 	ErrAPIsNotDeployed                  = "resources.apis_not_deployed"
 	ErrInvalidNodeGroupSelector         = "resources.invalid_node_group_selector"
+	ErrNoNodeGroups                     = "resources.no_node_groups"
 )
 
 func ErrorOperationIsOnlySupportedForKind(resource operator.DeployedResource, supportedKind userconfig.Kind, supportedKinds ...userconfig.Kind) error {
@@ -118,6 +119,13 @@ func ErrorInvalidNodeGroupSelector(selected string, availableNodeGroups []string
 	})
 }
 
+func ErrorNoNodeGroups() error {
+	return errors.WithStack(&errors.Error{
+		Kind:    ErrNoNodeGroups,
+		Message: fmt.Sprintf("your api cannot be deployed because your cluster doesn't have any node groups; create a node group with `cortex cluster configure CLUSTER_CONFIG_FILE`"),
+	})
+}
+
 func podResourceRequestsTable(api *userconfig.API, compute userconfig.Compute) string {
 	sidecarCPUNote := ""
 	sidecarMemNote := ""

pkg/operator/resources/validations.go

@@ -36,6 +36,10 @@ func ValidateClusterAPIs(apis []userconfig.API) error {
 		return spec.ErrorNoAPIs()
 	}
 
+	if len(config.ClusterConfig.NodeGroups) == 0 {
+		return ErrorNoNodeGroups()
+	}
+
 	virtualServices, err := config.K8s.ListVirtualServices(nil)
 	if err != nil {
 		return err

pkg/types/clusterconfig/availability_zones.go

@@ -47,9 +47,13 @@ func (cc *Config) setDefaultAvailabilityZones(awsClient *aws.Client) error {
 	}
 	instanceTypesSlice := instanceTypes.Slice()
 
-	zones, err := awsClient.ListSupportedAvailabilityZones(instanceTypesSlice[0], instanceTypesSlice[1:]...)
-	if err != nil {
-		// Try again without checking instance types
+	var zones strset.Set
+	var err error
+	if len(instanceTypesSlice) > 0 {
+		zones, err = awsClient.ListSupportedAvailabilityZones(instanceTypesSlice[0], instanceTypesSlice[1:]...)
+	}
+	if len(zones) == 0 || err != nil {
+		// Try without checking instance types
 		zones, err = awsClient.ListAvailabilityZonesInRegion()
 		if err != nil {
 			return nil // Let eksctl choose the availability zones
@@ -75,12 +79,6 @@ func (cc *Config) setDefaultAvailabilityZones(awsClient *aws.Client) error {
 }
 
 func (cc *Config) validateUserAvailabilityZones(awsClient *aws.Client) error {
-	instanceTypes := strset.New()
-	for _, ng := range cc.NodeGroups {
-		instanceTypes.Add(ng.InstanceType)
-	}
-	instanceTypesSlice := instanceTypes.Slice()
-
 	allZones, err := awsClient.ListAvailabilityZonesInRegion()
 	if err != nil {
 		return nil // Skip validation
@@ -92,15 +90,23 @@ func (cc *Config) validateUserAvailabilityZones(awsClient *aws.Client) error {
 		}
 	}
 
-	supportedZones, err := awsClient.ListSupportedAvailabilityZones(instanceTypesSlice[0], instanceTypesSlice[1:]...)
-	if err != nil {
-		// Skip validation instance-based validation
-		supportedZones = strset.Difference(allZones, _azBlacklist)
-	}
+	if len(cc.NodeGroups) > 0 {
+		instanceTypes := strset.New()
+		for _, ng := range cc.NodeGroups {
+			instanceTypes.Add(ng.InstanceType)
+		}
+		instanceTypesSlice := instanceTypes.Slice()
 
-	for _, userZone := range cc.AvailabilityZones {
-		if !supportedZones.Has(userZone) {
-			return ErrorUnsupportedAvailabilityZone(userZone, instanceTypesSlice[0], instanceTypesSlice[1:]...)
+		supportedZones, err := awsClient.ListSupportedAvailabilityZones(instanceTypesSlice[0], instanceTypesSlice[1:]...)
+		if err != nil {
+			// Skip validation instance-based validation
+			supportedZones = strset.Difference(allZones, _azBlacklist)
+		}
+
+		for _, userZone := range cc.AvailabilityZones {
+			if !supportedZones.Has(userZone) {
+				return ErrorUnsupportedAvailabilityZone(userZone, instanceTypesSlice[0], instanceTypesSlice[1:]...)
+			}
 		}
 	}
 

pkg/types/clusterconfig/cluster_config.go

@@ -517,8 +517,9 @@ var ManagedConfigStructFieldValidations = []*cr.StructFieldValidation{
 	{
 		StructField: "NodeGroups",
 		StructListValidation: &cr.StructListValidation{
-			Required:         true,
-			StructValidation: nodeGroupsFieldValidation,
+			AllowExplicitNull: true,
+			TreatNullAsEmpty:  true,
+			StructValidation:  nodeGroupsFieldValidation,
 		},
 	},
 	{
@@ -890,9 +891,6 @@ func (cc *CoreConfig) SQSNamePrefix() string {
 
 func (cc *Config) validate(awsClient *aws.Client) error {
 	numNodeGroups := len(cc.NodeGroups)
-	if numNodeGroups == 0 {
-		return ErrorNoNodeGroupSpecified()
-	}
 	if numNodeGroups > MaxNodePoolsOrGroups {
 		return ErrorMaxNumOfNodeGroupsReached(MaxNodePoolsOrGroups)
 	}

pkg/types/clusterconfig/errors.go

@@ -32,7 +32,6 @@ const (
 	ErrInvalidLegacyProvider                  = "clusterconfig.invalid_legacy_provider"
 	ErrDisallowedField                        = "clusterconfig.disallowed_field"
 	ErrInvalidRegion                          = "clusterconfig.invalid_region"
-	ErrNoNodeGroupSpecified                   = "clusterconfig.no_nodegroup_specified"
 	ErrNodeGroupMaxInstancesIsZero            = "clusterconfig.node_group_max_instances_is_zero"
 	ErrMaxNumOfNodeGroupsReached              = "clusterconfig.max_num_of_nodegroups_reached"
 	ErrDuplicateNodeGroupName                 = "clusterconfig.duplicate_nodegroup_name"
@@ -105,13 +104,6 @@ func ErrorInvalidRegion(region string) error {
 	})
 }
 
-func ErrorNoNodeGroupSpecified() error {
-	return errors.WithStack(&errors.Error{
-		Kind:    ErrNoNodeGroupSpecified,
-		Message: "no nodegroup was specified; please specify at least 1 nodegroup",
-	})
-}
-
 func ErrorNodeGroupMaxInstancesIsZero() error {
 	return errors.WithStack(&errors.Error{
 		Kind:    ErrNodeGroupMaxInstancesIsZero,