feat(provision): add support for thin provision lvm volumes (#30)

Signed-off-by: prateekpandey14 <[email protected]>

Author: prateekpandey14

deploy/lvm-operator.yaml

@@ -109,6 +109,15 @@ spec:
                 - "yes"
                 - "no"
                 type: string
+              thinProvision:
+                description: ThinProvision specifies whether logical volumes can be
+                  thinly provisioned. If it is set to "yes", then the LVM LocalPV
+                  Driver will create thinProvision i.e. logical volumes that are larger
+                  than the available extents.
+                enum:
+                - "yes"
+                - "no"
+                type: string
               volGroup:
                 description: VolGroup specifies the name of the volume group where
                   the volume has been created.
@@ -226,6 +235,15 @@ spec:
                 - "yes"
                 - "no"
                 type: string
+              thinProvision:
+                description: ThinProvision specifies whether logical volumes can be
+                  thinly provisioned. If it is set to "yes", then the LVM LocalPV
+                  Driver will create thinProvision i.e. logical volumes that are larger
+                  than the available extents.
+                enum:
+                - "yes"
+                - "no"
+                type: string
               volGroup:
                 description: VolGroup specifies the name of the volume group where
                   the volume has been created.

deploy/yamls/lvmsnapshot-crd.yaml

@@ -65,6 +65,15 @@ spec:
                 - "yes"
                 - "no"
                 type: string
+              thinProvision:
+                description: ThinProvision specifies whether logical volumes can be
+                  thinly provisioned. If it is set to "yes", then the LVM LocalPV
+                  Driver will create thinProvision i.e. logical volumes that are larger
+                  than the available extents.
+                enum:
+                - "yes"
+                - "no"
+                type: string
               volGroup:
                 description: VolGroup specifies the name of the volume group where
                   the volume has been created.

deploy/yamls/lvmvolume-crd.yaml

@@ -88,6 +88,15 @@ spec:
                 - "yes"
                 - "no"
                 type: string
+              thinProvision:
+                description: ThinProvision specifies whether logical volumes can be
+                  thinly provisioned. If it is set to "yes", then the LVM LocalPV
+                  Driver will create thinProvision i.e. logical volumes that are larger
+                  than the available extents.
+                enum:
+                - "yes"
+                - "no"
+                type: string
               volGroup:
                 description: VolGroup specifies the name of the volume group where
                   the volume has been created.

pkg/apis/openebs.io/lvm/v1alpha1/lvmvolume.go

@@ -76,6 +76,13 @@ type VolumeInfo struct {
 	// +kubebuilder:validation:Required
 	// +kubebuilder:validation:Enum=yes;no
 	Shared string `json:"shared,omitempty"`
+
+	// ThinProvision specifies whether logical volumes can be thinly provisioned.
+	// If it is set to "yes", then the LVM LocalPV Driver will create
+	// thinProvision i.e. logical volumes that are larger than the available extents.
+	// +kubebuilder:validation:Required
+	// +kubebuilder:validation:Enum=yes;no
+	ThinProvision string `json:"thinProvision,omitempty"`
 }
 
 // VolStatus string that specifies the current state of the volume provisioning request.

pkg/builder/volbuilder/volume.go

@@ -133,6 +133,12 @@ func (b *Builder) WithShared(shared string) *Builder {
 	return b
 }
 
+// WithThinProvision sets where thinProvision is enable or not
+func (b *Builder) WithThinProvision(thinProvision string) *Builder {
+	b.volume.Object.Spec.ThinProvision = thinProvision
+	return b
+}
+
 // WithVolGroup sets volume group name for creating volume
 func (b *Builder) WithVolGroup(vg string) *Builder {
 	if vg == "" {

pkg/driver/controller.go

@@ -271,7 +271,8 @@ func CreateLVMVolume(ctx context.Context, req *csi.CreateVolumeRequest,
 		WithVolGroup(params.VolumeGroup).
 		WithOwnerNode(owner).
 		WithVolumeStatus(lvm.LVMStatusPending).
-		WithShared(params.Shared).Build()
+		WithShared(params.Shared).
+		WithThinProvision(params.ThinProvision).Build()
 
 	if err != nil {
 		return nil, status.Error(codes.Internal, err.Error())

pkg/driver/params.go

@@ -27,9 +27,9 @@ type VolumeParams struct {
 	// provisioning logical volumes.
 	VolumeGroup string
 
-	Scheduler string
-	Shared    string
-
+	Scheduler     string
+	Shared        string
+	ThinProvision string
 	// extra optional metadata passed by external provisioner
 	// if enabled. See --extra-create-metadata flag for more details.
 	// https://github.com/kubernetes-csi/external-provisioner#recommended-optional-arguments
@@ -41,8 +41,9 @@ type VolumeParams struct {
 // NewVolumeParams parses the input params and instantiates new VolumeParams.
 func NewVolumeParams(m map[string]string) (*VolumeParams, error) {
 	params := &VolumeParams{ // set up defaults, if any.
-		Scheduler: CapacityWeighted,
-		Shared:    "no",
+		Scheduler:     CapacityWeighted,
+		Shared:        "no",
+		ThinProvision: "no",
 	}
 	// parameter keys may be mistyped from the CRD specification when declaring
 	// the storageclass, which kubectl validation will not catch. Because
@@ -53,8 +54,9 @@ func NewVolumeParams(m map[string]string) (*VolumeParams, error) {
 
 	// parse string params
 	stringParams := map[string]*string{
-		"scheduler": &params.Scheduler,
-		"shared":    &params.Shared,
+		"scheduler":     &params.Scheduler,
+		"shared":        &params.Shared,
+		"thinprovision": &params.ThinProvision,
 	}
 	for key, param := range stringParams {
 		value, ok := m[key]

pkg/lvm/lvm_util.go

@@ -76,17 +76,29 @@ func buildLVMCreateArgs(vol *apis.LVMVolume) []string {
 
 	volume := vol.Name
 	size := vol.Spec.Capacity + "b"
+	// thinpool name required for thinProvision volumes
+	pool := vol.Spec.VolGroup + "_thinpool"
 
 	if len(vol.Spec.Capacity) != 0 {
-		LVMVolArg = append(LVMVolArg, "-L", size)
+		// check if thin pool exists for given volumegroup requested thin volume
+		if strings.TrimSpace(vol.Spec.ThinProvision) != "yes" || !lvThinExists(vol.Spec.VolGroup, pool) {
+			LVMVolArg = append(LVMVolArg, "-L", size)
+		}
+	}
+
+	// command to create thinpool and thin volume if thinProvision is enabled
+	// `lvcreate -L 1G -T lvmvg/mythinpool -V 1G -n thinvol`
+	if strings.TrimSpace(vol.Spec.ThinProvision) == "yes" {
+		LVMVolArg = append(LVMVolArg, "-T", vol.Spec.VolGroup+"/"+pool, "-V", size)
 	}
 
 	if len(vol.Spec.VolGroup) != 0 {
 		LVMVolArg = append(LVMVolArg, "-n", volume)
 	}
 
-	LVMVolArg = append(LVMVolArg, vol.Spec.VolGroup)
-
+	if strings.TrimSpace(vol.Spec.ThinProvision) != "yes" {
+		LVMVolArg = append(LVMVolArg, vol.Spec.VolGroup)
+	}
 	return LVMVolArg
 }
 
@@ -392,3 +404,14 @@ func ListLVMVolumeGroup() ([]apis.VolumeGroup, error) {
 	}
 	return decodeVgsJSON(output)
 }
+
+// lvThinExists verifies if thin pool/volume already exists for given volumegroup
+func lvThinExists(vg string, name string) bool {
+	cmd := exec.Command("lvs", vg+"/"+name, "--noheadings", "-o", "lv_name")
+	out, err := cmd.CombinedOutput()
+	if err != nil {
+		klog.Infof("unable to list existing volumes:%v", err)
+		return false
+	}
+	return name == strings.TrimSpace(string(out))
+}