Ensure GCE disk name does not start with a number

As this could not have worked before, we don't have to worry about
compatability with existing users.

pkg/model/master_volumes.go

@@ -194,7 +194,11 @@ func (b *MasterVolumeBuilder) addGCEVolume(c *fi.ModelBuilderContext, name strin
 	tags[gce.GceLabelNameRolePrefix+"master"] = "master" // Can't start with a number
 	tags[gce.GceLabelNameEtcdClusterPrefix+etcd.Name] = gce.EncodeGCELabel(clusterSpec)
 
+	// GCE disk names must match the following regular expression: '[a-z](?:[-a-z0-9]{0,61}[a-z0-9])?'
 	name = strings.Replace(name, ".", "-", -1)
+	if strings.IndexByte("0123456789-", name[0]) != -1 {
+		name = "d" + name
+	}
 
 	t := &gcetasks.Disk{
 		Name:      s(name),

tests/integration/update_cluster/ha_gce/in-v1alpha2.yaml

@@ -14,19 +14,19 @@ spec:
   etcdClusters:
   - etcdMembers:
     - instanceGroup: master-us-test1-a
-      name: a
+      name: "1"
     - instanceGroup: master-us-test1-b
-      name: b
+      name: "2"
     - instanceGroup: master-us-test1-c
-      name: c
+      name: "3"
     name: main
   - etcdMembers:
     - instanceGroup: master-us-test1-a
-      name: a
+      name: "1"
     - instanceGroup: master-us-test1-b
-      name: b
+      name: "2"
     - instanceGroup: master-us-test1-c
-      name: c
+      name: "3"
     name: events
   iam:
     legacy: false

tests/integration/update_cluster/ha_gce/kubernetes.tf

@@ -15,43 +15,43 @@ provider "google" {
   region  = "us-test1"
 }
 
-resource "google_compute_disk" "a-etcd-events-ha-gce-example-com" {
-  name = "a-etcd-events-ha-gce-example-com"
+resource "google_compute_disk" "d1-etcd-events-ha-gce-example-com" {
+  name = "d1-etcd-events-ha-gce-example-com"
   type = "pd-ssd"
   size = 20
   zone = "us-test1-a"
 }
 
-resource "google_compute_disk" "a-etcd-main-ha-gce-example-com" {
-  name = "a-etcd-main-ha-gce-example-com"
+resource "google_compute_disk" "d1-etcd-main-ha-gce-example-com" {
+  name = "d1-etcd-main-ha-gce-example-com"
   type = "pd-ssd"
   size = 20
   zone = "us-test1-a"
 }
 
-resource "google_compute_disk" "b-etcd-events-ha-gce-example-com" {
-  name = "b-etcd-events-ha-gce-example-com"
+resource "google_compute_disk" "d2-etcd-events-ha-gce-example-com" {
+  name = "d2-etcd-events-ha-gce-example-com"
   type = "pd-ssd"
   size = 20
   zone = "us-test1-b"
 }
 
-resource "google_compute_disk" "b-etcd-main-ha-gce-example-com" {
-  name = "b-etcd-main-ha-gce-example-com"
+resource "google_compute_disk" "d2-etcd-main-ha-gce-example-com" {
+  name = "d2-etcd-main-ha-gce-example-com"
   type = "pd-ssd"
   size = 20
   zone = "us-test1-b"
 }
 
-resource "google_compute_disk" "c-etcd-events-ha-gce-example-com" {
-  name = "c-etcd-events-ha-gce-example-com"
+resource "google_compute_disk" "d3-etcd-events-ha-gce-example-com" {
+  name = "d3-etcd-events-ha-gce-example-com"
   type = "pd-ssd"
   size = 20
   zone = "us-test1-c"
 }
 
-resource "google_compute_disk" "c-etcd-main-ha-gce-example-com" {
-  name = "c-etcd-main-ha-gce-example-com"
+resource "google_compute_disk" "d3-etcd-main-ha-gce-example-com" {
+  name = "d3-etcd-main-ha-gce-example-com"
   type = "pd-ssd"
   size = 20
   zone = "us-test1-c"