firecracker: Add support for pseudo hotplug

Use the firecracker rescan logic to update the pre-attached drive. This allows us to emulate hotplug. Initially the drive backing stores are set to empty files on the host. Once the actual block based device or file is available swap the backing store. The rescan needs to be issued iff the VM is running. Signed-off-by: Manohar Castelino <[email protected]>
kata-containers · Dec 20, 2018 · fba2379 · fba2379
1 parent 22ebc09
commit fba2379
Showing 1 changed file with 12 additions and 8 deletions.
diff --git a/virtcontainers/fc.go b/virtcontainers/fc.go
@@ -537,14 +537,18 @@ func (fc *firecracker) fcUpdateBlockDrive(drive config.BlockDrive) error {
 		return err
 	}
 
-	actionParams := ops.NewCreateSyncActionParams()
-	actionInfo := &models.InstanceActionInfo{
-		ActionType: "BlockDeviceRescan",
-	}
-	actionParams.SetInfo(actionInfo)
-	_, err = fc.client().Operations.CreateSyncAction(actionParams)
-	if err != nil {
-		return err
+	// Rescan needs to used only if the VM is running
+	if fc.vmRunning() {
+		actionParams := ops.NewCreateSyncActionParams()
+		actionInfo := &models.InstanceActionInfo{
+			ActionType: "BlockDeviceRescan",
+			Payload:    driveID,
+		}
+		actionParams.SetInfo(actionInfo)
+		_, err = fc.client().Operations.CreateSyncAction(actionParams)
+		if err != nil {
+			return err
+		}
 	}
 
 	return nil