Add rootDiskAvailabilityZone to MachineClass

hack/api-reference/api.md

@@ -237,6 +237,18 @@ string
 </tr>
 <tr>
 <td>
+<code>rootDiskAvailabilityZone</code></br>
+<em>
+string
+</em>
+</td>
+<td>
+<em>(Optional)</em>
+<p>RootDiskAvailabilityZone is the availability zone of the root disk volume. It is only used if RootDiskType is set.<br />If unset, the availability zone of the machine is used. If set to the empty string, no availability zone is<br />passed to Cinder, which then uses its default availability zone. This allows for differing compute and volume<br />availability zones.</p>
+</td>
+</tr>
+<tr>
+<td>
 <code>useConfigDrive</code></br>
 <em>
 boolean

pkg/apis/openstack/types.go

@@ -51,6 +51,10 @@ type MachineProviderConfigSpec struct {
 	RootDiskSize int
 	// The type of the root disk type used for the instance
 	RootDiskType *string
+	// RootDiskAvailabilityZone is the availability zone of the root disk volume. It is only used if RootDiskType is set.
+	// If unset, the availability zone of the machine is used. If set to the empty string, no availability zone is
+	// passed to Cinder, which then uses its default availability zone.
+	RootDiskAvailabilityZone *string
 	// UseConfigDrive enables the use of configuration drives for the instance.
 	UseConfigDrive *bool
 	// ServerGroupID is the ID of the server group this instance should belong to.

pkg/apis/openstack/v1alpha1/types.go

@@ -58,6 +58,12 @@ type MachineProviderConfigSpec struct {
 	// The type of the root disk used for the instance.
 	// +optional
 	RootDiskType *string `json:"rootDiskType,omitempty"`
+	// RootDiskAvailabilityZone is the availability zone of the root disk volume. It is only used if RootDiskType is set.
+	// If unset, the availability zone of the machine is used. If set to the empty string, no availability zone is
+	// passed to Cinder, which then uses its default availability zone. This allows for differing compute and volume
+	// availability zones.
+	// +optional
+	RootDiskAvailabilityZone *string `json:"rootDiskAvailabilityZone,omitempty"`
 	// UseConfigDrive enables the use of configuration drives for the instance.
 	UseConfigDrive *bool `json:"useConfigDrive,omitempty"`
 	// ServerGroupID is the ID of the server group this instance should belong to.

pkg/apis/validation/validation.go

@@ -63,6 +63,9 @@ func validateMachineProviderConfig(providerConfig *openstack.MachineProviderConf
 	if providerConfig.Spec.RootDiskSize < 0 {
 		allErrs = append(allErrs, field.Required(fldPath.Child("rootDiskSize"), "RootDiskSize can not be negative"))
 	}
+	if providerConfig.Spec.RootDiskAvailabilityZone != nil && providerConfig.Spec.RootDiskType == nil {
+		allErrs = append(allErrs, field.Forbidden(fldPath.Child("rootDiskAvailabilityZone"), "\"rootDiskAvailabilityZone\" can only be set together with \"rootDiskType\""))
+	}
 
 	allErrs = append(allErrs, validateNetworks(providerConfig.Spec.Networks, providerConfig.Spec.PodNetworkCidr, providerConfig.Spec.PodNetworkCIDRs, field.NewPath("spec.networks"))...)
 	allErrs = append(allErrs, validateClassSpecTags(providerConfig.Spec.Tags, field.NewPath("spec.tags"))...)

pkg/apis/validation/validation_test.go

@@ -11,6 +11,7 @@ import (
 	. "github.com/onsi/gomega"
 	. "github.com/onsi/gomega/gstruct"
 	corev1 "k8s.io/api/core/v1"
+	"k8s.io/utils/ptr"
 
 	. "github.com/gardener/machine-controller-manager-provider-openstack/pkg/apis/cloudprovider"
 	api "github.com/gardener/machine-controller-manager-provider-openstack/pkg/apis/openstack"
@@ -47,6 +48,21 @@ var _ = Describe("Validation", func() {
 			}
 		})
 
+		Context("rootDiskAvailabilityZone", func() {
+			It("should fail if set without rootDiskType", func() {
+				machineProviderConfig.Spec.RootDiskAvailabilityZone = ptr.To("nova")
+				err := validateMachineProviderConfig(machineProviderConfig).ToAggregate()
+				Expect(err).To(HaveOccurred())
+			})
+
+			It("should succeed if set together with rootDiskType", func() {
+				machineProviderConfig.Spec.RootDiskAvailabilityZone = ptr.To("nova")
+				machineProviderConfig.Spec.RootDiskType = ptr.To("fast")
+				err := validateMachineProviderConfig(machineProviderConfig).ToAggregate()
+				Expect(err).ToNot(HaveOccurred())
+			})
+		})
+
 		Context("required fields", func() {
 			It("should return no error", func() {
 				err := validateMachineProviderConfig(machineProviderConfig).ToAggregate()

pkg/driver/executor/executor.go

@@ -358,6 +358,16 @@ func (ex *Executor) addBlockDeviceOpts(ctx context.Context, machineName,
 	return createOpts, nil
 }
 
+// rootDiskAvailabilityZone returns the availability zone to create the root disk volume in.
+// It defaults to the availability zone of the machine, but can be overridden (or emptied, to let Cinder choose its
+// default) to support clouds where compute and volume availability zones differ.
+func (ex *Executor) rootDiskAvailabilityZone() string {
+	if az := ex.Config.Spec.RootDiskAvailabilityZone; az != nil {
+		return *az
+	}
+	return ex.Config.Spec.AvailabilityZone
+}
+
 func (ex *Executor) ensureVolume(ctx context.Context, name, imageID string,
 	hintOpts volumes.SchedulerHintOptsBuilder) (string, error) {
 	var (
@@ -376,7 +386,7 @@ func (ex *Executor) ensureVolume(ctx context.Context, name, imageID string,
 			VolumeType:       *ex.Config.Spec.RootDiskType,
 			Size:             ex.Config.Spec.RootDiskSize,
 			ImageID:          imageID,
-			AvailabilityZone: ex.Config.Spec.AvailabilityZone,
+			AvailabilityZone: ex.rootDiskAvailabilityZone(),
 			Metadata:         ex.Config.Spec.Tags,
 		}, hintOpts)
 		if err != nil {

pkg/driver/executor/executor_test.go

@@ -550,4 +550,18 @@ var _ = Describe("Executor", func() {
 			Expect(err).ToNot(HaveOccurred())
 		})
 	})
+
+	Context("rootDiskAvailabilityZone", func() {
+		DescribeTable("should select the availability zone for the root disk volume",
+			func(rootDiskAZ *string, expected string) {
+				cfg.Spec.AvailabilityZone = "AZ1"
+				cfg.Spec.RootDiskAvailabilityZone = rootDiskAZ
+				ex := &Executor{Config: cfg}
+				Expect(ex.rootDiskAvailabilityZone()).To(Equal(expected))
+			},
+			Entry("defaults to the machine availability zone", nil, "AZ1"),
+			Entry("uses the configured volume availability zone", ptr.To("nova"), "nova"),
+			Entry("omits the availability zone if empty", ptr.To(""), ""),
+		)
+	})
 })