Refactor nodegroup validation, check IAM attrs

pkg/apis/eksctl.io/v1alpha3/validation.go

@@ -0,0 +1,33 @@
+package v1alpha3
+
+import (
+	"fmt"
+)
+
+func ValidateNodeGroup(i int, ng *NodeGroup) error {
+	path := fmt.Errorf("nodegroups[%d]", i)
+	if ng.Name == "" {
+		return fmt.Errorf("%s.name must be set", path)
+	}
+
+	if ng.IAM.InstanceRoleARN != "" {
+		p := fmt.Sprintf("%s.iam.instanceRoleARN and %s.iam", path, path)
+		if ng.IAM.InstanceRoleName != "" {
+			return fmt.Errorf("%s.instanceRoleName cannot be set at the same time", p)
+		}
+		if len(ng.IAM.AttachPolicyARNs) != 0 {
+			return fmt.Errorf("%s.attachPolicyARNs cannot be set at the same time", p)
+		}
+		if ng.IAM.WithAddonPolicies.AutoScaler {
+			return fmt.Errorf("%s.withAddonPolicies.autoScaler cannot be set at the same time", p)
+		}
+		if ng.IAM.WithAddonPolicies.ExternalDNS {
+			return fmt.Errorf("%s.withAddonPolicies.externalDNS cannot be set at the same time", p)
+		}
+		if ng.IAM.WithAddonPolicies.ImageBuilder {
+			return fmt.Errorf("%s.imageBuilder cannot be set at the same time", p)
+		}
+	}
+
+	return nil
+}

pkg/ctl/create/cluster.go

@@ -194,9 +194,11 @@ func doCreateCluster(p *api.ProviderConfig, cfg *api.ClusterConfig, nameArg stri
 		}
 
 		err := checkEachNodeGroup(cfg, func(i int, ng *api.NodeGroup) error {
-			if ng.Name == "" {
-				return fmt.Errorf("nodegroups[%d].name must be set", i)
+			if err := api.ValidateNodeGroup(i, ng); err != nil {
+				return err
 			}
+
+			// apply defaults
 			if ng.InstanceType == "" {
 				ng.InstanceType = api.DefaultNodeType
 			}
@@ -218,6 +220,7 @@ func doCreateCluster(p *api.ProviderConfig, cfg *api.ClusterConfig, nameArg stri
 					ng.VolumeType = api.DefaultNodeVolumeType
 				}
 			}
+
 			return nil
 		})
 		if err != nil {