Add validation on clustername

to allow for cluster name to be used as prefix for naming other azure resources
- max length of 44 characters
- no special characters allowed

Author: nader-ziada

api/v1alpha3/azurecluster_default_test.go

@@ -90,6 +90,9 @@ func TestVnetDefaults(t *testing.T) {
 			name:    "resource group vnet specified",
 			cluster: createValidCluster(),
 			output: &AzureCluster{
+				ObjectMeta: metav1.ObjectMeta{
+					Name: "test-cluster",
+				},
 				Spec: AzureClusterSpec{
 					NetworkSpec: NetworkSpec{
 						Vnet: VnetSpec{

api/v1alpha3/azurecluster_validation.go

@@ -26,6 +26,12 @@ import (
 )
 
 const (
+	// can't use: \/"'[]:|<>+=;,.?*@&, Can't start with underscore. Can't end with period or hyphen.
+	// not using . in the name to avoid issues when the name is part of DNS name
+	clusterNameRegex = `^[a-z][a-z0-9-]{0,44}[a-z0-9]$`
+	// max length of 44 to allow for cluster name to be used as a prefix for VMs and other resources that
+	// have limitations as outlined here https://docs.microsoft.com/en-us/azure/azure-resource-manager/management/resource-name-rules
+	clusterNameMaxLength = 44
 	// obtained from https://docs.microsoft.com/en-us/rest/api/resources/resourcegroups/createorupdate#uri-parameters
 	resourceGroupRegex = `^[-\w\._\(\)]+$`
 	// described in https://docs.microsoft.com/en-us/azure/azure-resource-manager/management/resource-name-rules
@@ -36,6 +42,7 @@ const (
 // validateCluster validates a cluster
 func (c *AzureCluster) validateCluster() error {
 	var allErrs field.ErrorList
+	allErrs = append(allErrs, c.validateClusterName()...)
 	allErrs = append(allErrs, c.validateClusterSpec()...)
 	if len(allErrs) == 0 {
 		return nil
@@ -53,6 +60,24 @@ func (c *AzureCluster) validateClusterSpec() field.ErrorList {
 		field.NewPath("spec").Child("networkSpec"))
 }
 
+// validateClusterName validates ClusterName
+func (c *AzureCluster) validateClusterName() field.ErrorList {
+	var allErrs field.ErrorList
+	if len(c.Name) > clusterNameMaxLength {
+		allErrs = append(allErrs, field.Invalid(field.NewPath("metadata").Child("Name"), c.Name,
+			fmt.Sprintf("Cluster Name longer than allowed length of %d characters", clusterNameMaxLength)))
+	}
+	if success, _ := regexp.MatchString(clusterNameRegex, c.Name); !success {
+		allErrs = append(allErrs, field.Invalid(field.NewPath("metadata").Child("Name"), c.Name,
+			fmt.Sprintf("Cluster Name doesn't match regex %s, can contain only lowercase alphanumeric characters and '-', must start/end with an alphanumeric character",
+				clusterNameRegex)))
+	}
+	if len(allErrs) == 0 {
+		return nil
+	}
+	return allErrs
+}
+
 // validateNetworkSpec validates a NetworkSpec
 func validateNetworkSpec(networkSpec NetworkSpec, fldPath *field.Path) field.ErrorList {
 	var allErrs field.ErrorList

api/v1alpha3/azurecluster_validation_test.go

@@ -20,9 +20,82 @@ import (
 	"testing"
 
 	. "github.com/onsi/gomega"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/util/validation/field"
 )
 
+func TestClusterNameValidation(t *testing.T) {
+	g := NewWithT(t)
+	tests := []struct {
+		name        string
+		clusterName string
+		wantErr     bool
+	}{
+		{
+			name:        "cluster name more than 44 characters",
+			clusterName: "vegkebfadbczdtevzjiyookobkdgfofjxmlquonomzoes",
+			wantErr:     true,
+		},
+		{
+			name:        "cluster name with letters",
+			clusterName: "cluster",
+			wantErr:     false,
+		},
+		{
+			name:        "cluster name with upper case letters",
+			clusterName: "clusterName",
+			wantErr:     true,
+		},
+		{
+			name:        "cluster name with hyphen",
+			clusterName: "test-cluster",
+			wantErr:     false,
+		},
+		{
+			name:        "cluster name with letters and numbers",
+			clusterName: "clustername1",
+			wantErr:     false,
+		},
+		{
+			name:        "cluster name with special characters",
+			clusterName: "cluster$?name",
+			wantErr:     true,
+		},
+		{
+			name:        "cluster name starting with underscore",
+			clusterName: "_clustername",
+			wantErr:     true,
+		},
+		{
+			name:        "cluster name with underscore",
+			clusterName: "cluster_name",
+			wantErr:     true,
+		},
+		{
+			name:        "cluster name with period",
+			clusterName: "cluster.name",
+			wantErr:     true,
+		},
+	}
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+
+			azureCluster := AzureCluster{
+				ObjectMeta: metav1.ObjectMeta{
+					Name: tc.clusterName,
+				},
+			}
+
+			allErrs := azureCluster.validateClusterName()
+			if tc.wantErr {
+				g.Expect(allErrs).ToNot(BeNil())
+			} else {
+				g.Expect(allErrs).To(BeNil())
+			}
+		})
+	}
+}
+
 func TestClusterWithPreexistingVnetValid(t *testing.T) {
 	g := NewWithT(t)
 
@@ -539,6 +612,9 @@ func TestIngressRules(t *testing.T) {
 
 func createValidCluster() *AzureCluster {
 	return &AzureCluster{
+		ObjectMeta: metav1.ObjectMeta{
+			Name: "test-cluster",
+		},
 		Spec: AzureClusterSpec{
 			NetworkSpec: createValidNetworkSpec(),
 		},

docs/development.md

@@ -219,6 +219,8 @@ The steps below are provided in a convenient script in [hack/create-dev-cluster.
 CLUSTER_NAME=<my-capz-cluster-name> ./hack/create-dev-cluster.sh
 ```
 
+   NOTE: `CLUSTER_NAME` can only include letters, numbers, and hyphens and can't be longer than 44 characters.
+
 ##### Building and pushing dev images
 
 1. To build images with custom tags,