mantle/kola/qemuexec: Add a disk when booting from ISO

Most of the time people probably want to test an install workflow
and they can't really do that if only the ISO is attached to the
VM via a CDROM drive (read only media). Let's add a disk by default
for convenience.

Author: dustymabe

mantle/cmd/kola/qemuexec.go

@@ -125,6 +125,41 @@ func parseBindOpt(s string) (string, string, error) {
 	return parts[0], parts[1], nil
 }
 
+// buildDiskFromOptions generates a disk image template using the process-global
+// defaults that were parsed from command line arguments.
+func buildDiskFromOptions() *platform.Disk {
+	channel := "virtio"
+	if kola.QEMUOptions.Nvme {
+		channel = "nvme"
+	}
+	sectorSize := 0
+	if kola.QEMUOptions.Native4k {
+		sectorSize = 4096
+	}
+	options := []string{}
+	if kola.QEMUOptions.DriveOpts != "" {
+		options = append(options, strings.Split(kola.QEMUOptions.DriveOpts, ",")...)
+	}
+	// If there was no disk image specified and no size then just
+	// default to an arbitrary value of 12G for the blank disk image.
+	size := kola.QEMUOptions.DiskSize
+	if kola.QEMUOptions.DiskImage == "" && kola.QEMUOptions.DiskSize == "" {
+		size = "12G"
+	}
+	// Build the disk definition. Note that if kola.QEMUOptions.DiskImage is
+	// "" we'll just end up with a blank disk image, which is what we want.
+	disk := &platform.Disk{
+		BackingFile:   kola.QEMUOptions.DiskImage,
+		Channel:       channel,
+		Size:          size,
+		SectorSize:    sectorSize,
+		DriveOpts:     options,
+		MultiPathDisk: kola.QEMUOptions.MultiPathDisk,
+		NbdDisk:       kola.QEMUOptions.NbdDisk,
+	}
+	return disk
+}
+
 func runQemuExec(cmd *cobra.Command, args []string) error {
 	var err error
 
@@ -283,36 +318,22 @@ func runQemuExec(cmd *cobra.Command, args []string) error {
 		builder.Firmware = kola.QEMUOptions.Firmware
 	}
 	if kola.QEMUOptions.DiskImage != "" {
-		channel := "virtio"
-		if kola.QEMUOptions.Nvme {
-			channel = "nvme"
-		}
-		sectorSize := 0
-		if kola.QEMUOptions.Native4k {
-			sectorSize = 4096
-		}
-		options := []string{}
-		if kola.QEMUOptions.DriveOpts != "" {
-			options = append(options, strings.Split(kola.QEMUOptions.DriveOpts, ",")...)
+		if err := builder.AddBootDisk(buildDiskFromOptions()); err != nil {
+			return err
 		}
-		err = builder.AddBootDisk(&platform.Disk{
-			BackingFile:   kola.QEMUOptions.DiskImage,
-			Channel:       channel,
-			Size:          kola.QEMUOptions.DiskSize,
-			SectorSize:    sectorSize,
-			DriveOpts:     options,
-			MultiPathDisk: kola.QEMUOptions.MultiPathDisk,
-			NbdDisk:       kola.QEMUOptions.NbdDisk,
-		})
 		if err != nil {
 			return err
 		}
 	}
 	if kola.QEMUIsoOptions.IsoPath != "" {
-		err := builder.AddIso(kola.QEMUIsoOptions.IsoPath, "", kola.QEMUIsoOptions.AsDisk)
+		err := builder.AddIso(kola.QEMUIsoOptions.IsoPath, "bootindex=3", kola.QEMUIsoOptions.AsDisk)
 		if err != nil {
 			return err
 		}
+		// Add a blank disk (this is a disk we can install to)
+		if err := builder.AddBootDisk(buildDiskFromOptions()); err != nil {
+			return err
+		}
 	}
 	builder.Hostname = hostname
 	// for historical reasons, both --memory and --qemu-memory are supported

mantle/platform/qemu.go

@@ -1077,18 +1077,22 @@ func (builder *QemuBuilder) addDiskImpl(disk *Disk, primary bool) error {
 		return err
 	}
 	if primary {
-		// If the board doesn't support -fw_cfg or we were explicitly
-		// requested, inject via libguestfs on the primary disk.
-		if err := builder.renderIgnition(); err != nil {
-			return errors.Wrapf(err, "rendering ignition")
-		}
-		requiresInjection := builder.ConfigFile != "" && builder.ForceConfigInjection
-		if requiresInjection || builder.AppendFirstbootKernelArgs != "" || builder.AppendKernelArgs != "" {
-			if err := setupPreboot(builder.architecture, builder.ConfigFile, builder.AppendFirstbootKernelArgs, builder.AppendKernelArgs,
-				disk.dstFileName, disk.SectorSize); err != nil {
-				return errors.Wrapf(err, "ignition injection with guestfs failed")
+		// Only try to inject config if it hasn't already been injected somewhere
+		// else, which can happen when running an ISO install.
+		if !builder.configInjected {
+			// If the board doesn't support -fw_cfg or we were explicitly
+			// requested, inject via libguestfs on the primary disk.
+			if err := builder.renderIgnition(); err != nil {
+				return errors.Wrapf(err, "rendering ignition")
+			}
+			requiresInjection := builder.ConfigFile != "" && builder.ForceConfigInjection
+			if requiresInjection || builder.AppendFirstbootKernelArgs != "" || builder.AppendKernelArgs != "" {
+				if err := setupPreboot(builder.architecture, builder.ConfigFile, builder.AppendFirstbootKernelArgs, builder.AppendKernelArgs,
+					disk.dstFileName, disk.SectorSize); err != nil {
+					return errors.Wrapf(err, "ignition injection with guestfs failed")
+				}
+				builder.configInjected = true
 			}
-			builder.configInjected = true
 		}
 	}
 	diskOpts := disk.DeviceOpts