Merge pull request lxc#2282 from bensmrs/eject-disk

Implement disk ejection

Author: stgraber

doc/api-extensions.md

@@ -2838,3 +2838,7 @@ on schedule.
 This adds tracking of CPU address sizes in the resources API.
 The main use of this is within clusters to calculate a cluster-wide
 maximum memory amount for hotplugging into virtual machines.
+
+## `disk_attached`
+
+This introduces a new `attached` property to disk devices describing whether disks are attached or ejected.

doc/config_options.txt

@@ -42,6 +42,14 @@ User keys can be used in search.
 
 <!-- config group cluster_group-common end -->
 <!-- config group devices-disk start -->
+```{config:option} attached devices-disk
+:default: "`true`"
+:required: "no"
+:shortdesc: "Only for VMs: Whether the disk is attached or ejected"
+:type: "bool"
+
+```
+
 ```{config:option} boot.priority devices-disk
 :required: "no"
 :shortdesc: "Boot priority for VMs (higher value boots first)"

internal/server/device/config/device_runconfig.go

@@ -31,6 +31,7 @@ type MountEntryItem struct {
 	OwnerShift string      // Ownership shifting mode, use constants MountOwnerShiftNone, MountOwnerShiftStatic or MountOwnerShiftDynamic.
 	Limits     *DiskLimits // Disk limits.
 	Size       int64       // Expected disk size in bytes.
+	Attached   bool        // Whether the disk is attached
 }
 
 // RootFSEntryItem represents the root filesystem options for an Instance.

internal/server/device/disk.go

@@ -363,6 +363,15 @@ func (d *disk) validateConfig(instConf instance.ConfigReader) error {
 		//  required: no
 		//  shortdesc: Only for VMs: Override the bus for the device
 		"io.bus": validate.Optional(validate.IsOneOf("nvme", "virtio-blk", "virtio-scsi", "auto", "9p", "virtiofs", "usb")),
+
+		// gendoc:generate(entity=devices, group=disk, key=attached)
+		//
+		// ---
+		//  type: bool
+		//  default: `true`
+		//  required: no
+		//  shortdesc: Only for VMs: Whether the disk is attached or ejected
+		"attached": validate.Optional(validate.IsBool),
 	}
 
 	err := d.config.Validate(rules)
@@ -570,6 +579,16 @@ func (d *disk) validateConfig(instConf instance.ConfigReader) error {
 					return err
 				}
 
+				if d.config["attached"] != "" {
+					if instConf.Type() == instancetype.Container {
+						return errors.New("Attached configuration cannot be applied to containers")
+					} else if instConf.Type() == instancetype.Any {
+						return errors.New("Attached configuration cannot be applied to profiles")
+					} else if contentType != db.StoragePoolVolumeContentTypeISO {
+						return errors.New("Attached configuration can only be applied to ISO volumes")
+					}
+				}
+
 				if contentType == db.StoragePoolVolumeContentTypeBlock {
 					if instConf.Type() == instancetype.Container {
 						return errors.New("Custom block volumes cannot be used on containers")
@@ -1038,6 +1057,9 @@ func (d *disk) startVM() (*deviceConfig.RunConfig, error) {
 		opts = append(opts, fmt.Sprintf("cache=%s", d.config["io.cache"]))
 	}
 
+	// Setup the attached status.
+	attached := util.IsTrueOrEmpty(d.config["attached"])
+
 	// Add I/O limits if set.
 	var diskLimits *deviceConfig.DiskLimits
 	if d.config["limits.read"] != "" || d.config["limits.write"] != "" || d.config["limits.max"] != "" {
@@ -1094,10 +1116,11 @@ func (d *disk) startVM() (*deviceConfig.RunConfig, error) {
 		// Encode the file descriptor and original isoPath into the DevPath field.
 		runConf.Mounts = []deviceConfig.MountEntryItem{
 			{
-				DevPath: fmt.Sprintf("%s:%d:%s", DiskFileDescriptorMountPrefix, f.Fd(), isoPath),
-				DevName: d.name,
-				FSType:  "iso9660",
-				Opts:    opts,
+				DevPath:  fmt.Sprintf("%s:%d:%s", DiskFileDescriptorMountPrefix, f.Fd(), isoPath),
+				DevName:  d.name,
+				FSType:   "iso9660",
+				Opts:     opts,
+				Attached: attached,
 			},
 		}
 
@@ -1124,10 +1147,11 @@ func (d *disk) startVM() (*deviceConfig.RunConfig, error) {
 		// Encode the file descriptor and original isoPath into the DevPath field.
 		runConf.Mounts = []deviceConfig.MountEntryItem{
 			{
-				DevPath: fmt.Sprintf("%s:%d:%s", DiskFileDescriptorMountPrefix, f.Fd(), isoPath),
-				DevName: d.name,
-				FSType:  "iso9660",
-				Opts:    opts,
+				DevPath:  fmt.Sprintf("%s:%d:%s", DiskFileDescriptorMountPrefix, f.Fd(), isoPath),
+				DevName:  d.name,
+				FSType:   "iso9660",
+				Opts:     opts,
+				Attached: attached,
 			},
 		}
 
@@ -1142,19 +1166,21 @@ func (d *disk) startVM() (*deviceConfig.RunConfig, error) {
 			clusterName, userName := d.cephCreds()
 			runConf.Mounts = []deviceConfig.MountEntryItem{
 				{
-					DevPath: DiskGetRBDFormat(clusterName, userName, fields[0], fields[1]),
-					DevName: d.name,
-					Opts:    opts,
-					Limits:  diskLimits,
+					DevPath:  DiskGetRBDFormat(clusterName, userName, fields[0], fields[1]),
+					DevName:  d.name,
+					Opts:     opts,
+					Limits:   diskLimits,
+					Attached: attached,
 				},
 			}
 		} else {
 			// Default to block device or image file passthrough first.
 			mount := deviceConfig.MountEntryItem{
-				DevPath: d.config["source"],
-				DevName: d.name,
-				Opts:    opts,
-				Limits:  diskLimits,
+				DevPath:  d.config["source"],
+				DevName:  d.name,
+				Opts:     opts,
+				Limits:   diskLimits,
+				Attached: attached,
 			}
 
 			// Mount the pool volume and update srcPath to mount path so it can be recognised as dir
@@ -1208,10 +1234,11 @@ func (d *disk) startVM() (*deviceConfig.RunConfig, error) {
 					}
 
 					mount := deviceConfig.MountEntryItem{
-						DevPath: DiskGetRBDFormat(clusterName, userName, poolName, d.config["source"]),
-						DevName: d.name,
-						Opts:    opts,
-						Limits:  diskLimits,
+						DevPath:  DiskGetRBDFormat(clusterName, userName, poolName, d.config["source"]),
+						DevName:  d.name,
+						Opts:     opts,
+						Limits:   diskLimits,
+						Attached: attached,
 					}
 
 					if contentType == db.StoragePoolVolumeContentTypeISO {
@@ -1410,9 +1437,10 @@ func (d *disk) postStart() error {
 
 // Update applies configuration changes to a started device.
 func (d *disk) Update(oldDevices deviceConfig.Devices, isRunning bool) error {
+	expandedDevices := d.inst.ExpandedDevices()
+
 	if internalInstance.IsRootDiskDevice(d.config) {
 		// Make sure we have a valid root disk device (and only one).
-		expandedDevices := d.inst.ExpandedDevices()
 		newRootDiskDeviceKey, _, err := internalInstance.GetRootDiskDevice(expandedDevices.CloneNative())
 		if err != nil {
 			return fmt.Errorf("Detect root disk device: %w", err)
@@ -1486,7 +1514,7 @@ func (d *disk) Update(oldDevices deviceConfig.Devices, isRunning bool) error {
 		}
 	}
 
-	// Only apply IO limits if instance is running.
+	// Only apply IO limits and attach/detach logic if instance is running.
 	if isRunning {
 		runConf := deviceConfig.RunConfig{}
 
@@ -1518,6 +1546,20 @@ func (d *disk) Update(oldDevices deviceConfig.Devices, isRunning bool) error {
 					Limits:  diskLimits,
 				},
 			}
+
+			oldAttached := util.IsTrueOrEmpty(oldDevices[d.name]["attached"])
+			newAttached := util.IsTrueOrEmpty(expandedDevices[d.name]["attached"])
+			if !oldAttached && newAttached {
+				runConf.Mounts = append(runConf.Mounts, deviceConfig.MountEntryItem{
+					DevName:  d.name,
+					Attached: true,
+				})
+			} else if oldAttached && !newAttached {
+				runConf.Mounts = append(runConf.Mounts, deviceConfig.MountEntryItem{
+					DevName:  d.name,
+					Attached: false,
+				})
+			}
 		}
 
 		err := d.inst.DeviceEventHandler(&runConf)