fix: use annotation for MirageOS block device name

pkg/unikontainers/config.go

@@ -45,6 +45,7 @@ const (
 	annotBlock         = "com.urunc.unikernel.block"
 	annotBlockMntPoint = "com.urunc.unikernel.blkMntPoint"
 	annotMountRootfs   = "com.urunc.unikernel.mountRootfs"
+	annotSolo5BlkDev   = "com.urunc.unikernel.blkDev"
 )
 
 // A UnikernelConfig struct holds the info provided by bima image on how to execute our unikernel
@@ -58,6 +59,7 @@ type UnikernelConfig struct {
 	Block            string `json:"com.urunc.unikernel.block,omitempty"`
 	BlkMntPoint      string `json:"com.urunc.unikernel.blkMntPoint,omitempty"`
 	MountRootfs      string `json:"com.urunc.unikernel.mountRootfs"`
+	Solo5BlkDev      string `json:"com.urunc.unikernel.blkDev,omitempty"`
 }
 
 // validate checks if the mandatory configuration fields are present.
@@ -119,6 +121,7 @@ func getConfigFromSpec(spec *specs.Spec) *UnikernelConfig {
 	block := spec.Annotations[annotBlock]
 	blkMntPoint := spec.Annotations[annotBlockMntPoint]
 	MountRootfs := spec.Annotations[annotMountRootfs]
+	solo5BlkDev := spec.Annotations[annotSolo5BlkDev]
 	uniklog.WithFields(logrus.Fields{
 		"unikernelType":    tryDecode(unikernelType),
 		"unikernelVersion": tryDecode(unikernelVersion),
@@ -129,6 +132,7 @@ func getConfigFromSpec(spec *specs.Spec) *UnikernelConfig {
 		"block":            tryDecode(block),
 		"blkMntPoint":      tryDecode(blkMntPoint),
 		"mountRootfs":      tryDecode(MountRootfs),
+		"solo5BlkDev":      tryDecode(solo5BlkDev),
 	}).WithField("source", "spec").Debug("urunc annotations")
 
 	return &UnikernelConfig{
@@ -141,6 +145,7 @@ func getConfigFromSpec(spec *specs.Spec) *UnikernelConfig {
 		Block:            block,
 		BlkMntPoint:      blkMntPoint,
 		MountRootfs:      MountRootfs,
+		Solo5BlkDev:      solo5BlkDev,
 	}
 }
 
@@ -180,6 +185,7 @@ func getConfigFromJSON(jsonFilePath string) (*UnikernelConfig, error) {
 		"block":            tryDecode(conf.Block),
 		"blkMntPoint":      tryDecode(conf.BlkMntPoint),
 		"mountRootfs":      tryDecode(conf.MountRootfs),
+		"solo5BlkDev":      tryDecode(conf.Solo5BlkDev),
 	}).WithField("source", uruncJSONFilename).Debug("urunc annotations")
 
 	return &conf, nil
@@ -250,6 +256,12 @@ func (c *UnikernelConfig) decode() error {
 	}
 	c.MountRootfs = string(decoded)
 
+	decoded, err = base64.StdEncoding.DecodeString(c.Solo5BlkDev)
+	if err != nil {
+		return fmt.Errorf("failed to decode blkDev: %v", err)
+	}
+	c.Solo5BlkDev = string(decoded)
+
 	return nil
 }
 
@@ -283,6 +295,9 @@ func (c *UnikernelConfig) Map() map[string]string {
 	if c.MountRootfs != "" {
 		myMap[annotMountRootfs] = c.MountRootfs
 	}
+	if c.Solo5BlkDev != "" {
+		myMap[annotSolo5BlkDev] = c.Solo5BlkDev
+	}
 
 	return myMap
 }

pkg/unikontainers/config_test.go

@@ -38,6 +38,7 @@ func TestGetConfigFromSpec(t *testing.T) {
 				annotBlock:         "block1",
 				annotBlockMntPoint: "point1",
 				annotMountRootfs:   "true",
+				annotSolo5BlkDev:   "mydisk",
 			},
 		}
 
@@ -50,6 +51,7 @@ func TestGetConfigFromSpec(t *testing.T) {
 			Block:           "block1",
 			BlkMntPoint:     "point1",
 			MountRootfs:     "true",
+			Solo5BlkDev:     "mydisk",
 		}
 
 		config := getConfigFromSpec(spec)
@@ -239,6 +241,7 @@ func TestMap(t *testing.T) {
 			Block:           "block_value",
 			BlkMntPoint:     "point_value",
 			MountRootfs:     "false",
+			Solo5BlkDev:     "blkdev_value",
 		}
 		expectedMap := map[string]string{
 			annotCmdLine:       "cmd_value",
@@ -249,6 +252,7 @@ func TestMap(t *testing.T) {
 			annotBlock:         "block_value",
 			annotBlockMntPoint: "point_value",
 			annotMountRootfs:   "false",
+			annotSolo5BlkDev:   "blkdev_value",
 		}
 		resultMap := config.Map()
 		assert.Equal(t, expectedMap, resultMap)

pkg/unikontainers/types/types.go

@@ -86,10 +86,12 @@ type UnikernelParams struct {
 	Monitor    string   // The monitor where guest will execute
 	Version    string   // The version of the unikernel
 	InitrdPath string   // The path to the initrd of the unikernel
-	Net        NetDevParams
-	Block      []BlockDevParams
-	Rootfs     RootfsParams  // Information about rootfs
-	ProcConf   ProcessConfig // Information for the process execution inside the guest
+	// Solo5BlkDevName is the Solo5 block device name declared at build time
+	Solo5BlkDevName string
+	Net             NetDevParams
+	Block           []BlockDevParams
+	Rootfs          RootfsParams  // Information about rootfs
+	ProcConf        ProcessConfig // Information for the process execution inside the guest
 }
 
 // ExecArgs holds the data required by Execve to start the VMM

pkg/unikontainers/unikernels/mirage.go

@@ -24,10 +24,11 @@ import (
 const MirageUnikernel string = "mirage"
 
 type Mirage struct {
-	Command string
-	Monitor string
-	Net     MirageNet
-	Block   []MirageBlock
+	Command         string
+	Monitor         string
+	Net             MirageNet
+	Block           []MirageBlock
+	solo5BlkDevName string
 }
 
 type MirageNet struct {
@@ -83,7 +84,7 @@ func (m *Mirage) MonitorBlockCli() []types.MonitorBlockArgs {
 		// how MirageOS handles/configures them.
 		return []types.MonitorBlockArgs{
 			{
-				ID:   "storage",
+				ID:   m.solo5BlkDevName,
 				Path: m.Block[0].HostPath,
 			},
 		}
@@ -118,6 +119,12 @@ func (m *Mirage) Init(data types.UnikernelParams) error {
 	m.Command = strings.Join(data.CmdLine, " ")
 	m.Monitor = data.Monitor
 
+	if data.Solo5BlkDevName != "" {
+		m.solo5BlkDevName = data.Solo5BlkDevName
+	} else {
+		m.solo5BlkDevName = "storage"
+	}
+
 	return nil
 }
 

pkg/unikontainers/unikernels/mirage_test.go

@@ -73,3 +73,33 @@ func TestMirageInitSubnetMask(t *testing.T) {
 		})
 	}
 }
+
+func TestMirageSolo5BlkDevName(t *testing.T) {
+	t.Run("uses block device name from annotation", func(t *testing.T) {
+		t.Parallel()
+		m := &Mirage{}
+		err := m.Init(types.UnikernelParams{
+			Monitor:         "hvt",
+			Solo5BlkDevName: "mydisk",
+			Block:           []types.BlockDevParams{{Source: "/path/to/img"}},
+		})
+		assert.NoError(t, err)
+		args := m.MonitorBlockCli()
+		assert.Len(t, args, 1)
+		assert.Equal(t, "mydisk", args[0].ID)
+		assert.Equal(t, "/path/to/img", args[0].Path)
+	})
+
+	t.Run("falls back to storage when annotation is absent", func(t *testing.T) {
+		t.Parallel()
+		m := &Mirage{}
+		err := m.Init(types.UnikernelParams{
+			Monitor: "hvt",
+			Block:   []types.BlockDevParams{{Source: "/path/to/img"}},
+		})
+		assert.NoError(t, err)
+		args := m.MonitorBlockCli()
+		assert.Len(t, args, 1)
+		assert.Equal(t, "storage", args[0].ID)
+	})
+}

pkg/unikontainers/unikontainers.go

@@ -391,11 +391,12 @@ func (u *Unikontainer) Exec(metrics m.Writer) error {
 	// UnikernelParams
 	// populate unikernel params
 	unikernelParams := types.UnikernelParams{
-		CmdLine:  u.Spec.Process.Args,
-		EnvVars:  u.Spec.Process.Env,
-		Monitor:  vmmType,
-		Version:  unikernelVersion,
-		ProcConf: procAttrs,
+		CmdLine:         u.Spec.Process.Args,
+		EnvVars:         u.Spec.Process.Env,
+		Monitor:         vmmType,
+		Version:         unikernelVersion,
+		ProcConf:        procAttrs,
+		Solo5BlkDevName: u.State.Annotations[annotSolo5BlkDev],
 	}
 	if len(unikernelParams.CmdLine) == 0 {
 		unikernelParams.CmdLine = strings.Fields(u.State.Annotations[annotCmdLine])