virter: add pool option to Disk

We may want to attach "dynamic" disks to a VM that are stored in a
different storage pool than the default one.

So allow users to specify a "pool=..." option on the command line, which
changes the storage location of the disk to the specified pool.

cmd/disk.go

@@ -12,6 +12,7 @@ type DiskArg struct {
 	Size   Size   `arg:"size"`
 	Format string `arg:"format,qcow2"`
 	Bus    string `arg:"bus,virtio"`
+	Pool   string `arg:"pool,"`
 }
 
 type Size struct {
@@ -36,6 +37,7 @@ func (d *DiskArg) GetName() string    { return d.Name }
 func (d *DiskArg) GetSizeKiB() uint64 { return d.Size.KiB }
 func (d *DiskArg) GetFormat() string  { return d.Format }
 func (d *DiskArg) GetBus() string     { return d.Bus }
+func (d *DiskArg) GetPool() string    { return d.Pool }
 
 // Set implements flag.Value.Set.
 func (d *DiskArg) Set(str string) error {

cmd/disk_test.go

@@ -20,12 +20,13 @@ func TestFromFlag(t *testing.T) {
 			expectError: true,
 		}, {
 			name:  "full spec parses",
-			input: "name=test,size=5GiB,format=qcow2,bus=virtio",
+			input: "name=test,size=5GiB,format=qcow2,bus=virtio,pool=mypool",
 			expect: cmd.DiskArg{
 				Name:   "test",
 				Size:   cmd.Size{KiB: uint64(5 * unit.G / unit.K)},
 				Format: "qcow2",
 				Bus:    "virtio",
+				Pool:   "mypool",
 			},
 		}, {
 			name:  "only required args parses",

cmd/vm_run.go

@@ -300,7 +300,7 @@ func vmRunCommand() *cobra.Command {
 	// and then manually marshal them to Disks.
 	// If this ever gets implemented in pflag , we will be able to solve this
 	// in a much smoother way.
-	runCmd.Flags().StringArrayVarP(&diskStrings, "disk", "d", []string{}, `Add a disk to the VM. Format: "name=disk1,size=100MiB,format=qcow2,bus=virtio". Can be specified multiple times`)
+	runCmd.Flags().StringArrayVarP(&diskStrings, "disk", "d", []string{}, `Add a disk to the VM. Format: "name=disk1,size=100MiB,format=qcow2,bus=virtio,pool=mypool". Can be specified multiple times`)
 	runCmd.Flags().StringArrayVarP(&nicStrings, "nic", "i", []string{}, `Add a NIC to the VM. Format: "type=network,source=some-net-name". Type can also be "bridge", in which case the source is the bridge device name. Additional config options are "model" (default: virtio) and "mac" (default chosen by libvirt). Can be specified multiple times`)
 	runCmd.Flags().StringArrayVarP(&mountStrings, "mount", "v", []string{}, `Mount a host path in the VM, like a bind mount. Format: "host=/path/on/host,vm=/path/in/vm"`)
 

internal/virter/libvirtxml.go

@@ -101,9 +101,13 @@ func (v *Virter) vmXML(vm VMConfig, mac string, meta *VMMeta) (string, error) {
 		VMDisk{device: VMDiskDeviceCDROM, poolName: v.provisionStoragePool.Name, volumeName: DynamicLayerName(ciDataVolumeName(vm.Name)), bus: "scsi", format: "raw"},
 	}
 	for _, d := range vm.Disks {
+		pool := d.GetPool()
+		if pool == "" {
+			pool = v.provisionStoragePool.Name
+		}
 		vmDisks = append(vmDisks, VMDisk{
 			device:     VMDiskDeviceDisk,
-			poolName:   v.provisionStoragePool.Name,
+			poolName:   pool,
 			volumeName: DynamicLayerName(diskVolumeName(vm.Name, d.GetName())),
 			bus:        d.GetBus(),
 			format:     d.GetFormat(),

internal/virter/virter.go

@@ -113,6 +113,7 @@ type Disk interface {
 	GetSizeKiB() uint64
 	GetFormat() string
 	GetBus() string
+	GetPool() string
 }
 
 type NICType string

internal/virter/vm.go

@@ -51,7 +51,11 @@ func (v *Virter) anyImageExists(vmConfig VMConfig) (bool, error) {
 	}
 
 	for _, d := range vmConfig.Disks {
-		imgs = append(imgs, imageAndPool{diskVolumeName(vmName, d.GetName()), v.provisionStoragePool})
+		pool, err := v.lookupPool(d.GetPool())
+		if err != nil {
+			return false, fmt.Errorf("failed to lookup libvirt pool: %w", err)
+		}
+		imgs = append(imgs, imageAndPool{diskVolumeName(vmName, d.GetName()), pool})
 	}
 
 	for _, img := range imgs {
@@ -164,7 +168,11 @@ func (v *Virter) VMRun(vmConfig VMConfig) error {
 
 	for _, d := range vmConfig.Disks {
 		log.Printf("Create volume '%s'", d.GetName())
-		_, err = v.NewDynamicLayer(diskVolumeName(vmConfig.Name, d.GetName()), v.provisionStoragePool, WithCapacity(d.GetSizeKiB()), WithFormat(d.GetFormat()))
+		pool, err := v.lookupPool(d.GetPool())
+		if err != nil {
+			return fmt.Errorf("failed to lookup libvirt pool %s: %w", d.GetPool(), err)
+		}
+		_, err = v.NewDynamicLayer(diskVolumeName(vmConfig.Name, d.GetName()), pool, WithCapacity(d.GetSizeKiB()), WithFormat(d.GetFormat()))
 		if err != nil {
 			return err
 		}