GNet Solutions » GNU/Linux Administration

While managing a small NodeJS instance, I decided to upgrade to the newest development branch of the software I am using. Since I am using VirtualBox, I chose take advantage of the snapshot capability; by taking a preliminary snapshot and then upgrading, I can then revert to that snapshot if the upgrade fails. It's the perfect server undo button.

Taking a snapshot of a VM¶

• Take a snapshot of a virtual machine
  

  VBoxManage snapshot "examplevm" take "prebackup" --live
  

  
  NOTE: The above command will take a live snapshot of the virtual machine, without interrupting any functions the VM is providing. The --pause command can be used to pause the VM while snapshotting.
  • After the snapshot creation is completed, you can power off the machine and restore it:
    

    VBoxManage snapshot "examplevm" restorecurrent
    

Revert Snapshot¶

• To Discard current changes
  

  VBoxManage snapshot "examplevm" discardcurrent
  

• Revert to last snapshot:
  

  VBoxManage snapshot "examplevm" discardcurrent
  

• To see Snapshot information about a particular VM
  

  VBoxManage snapshot "examplevm" discard "prebackup" 
  

Merging snapshots into a base VDI¶

If there is a need to apply the changes made since the snapshot was taken, then merging the snapshot that was taken into the Virtual Disk Image used by the virtual machine is necessary.

• To merge a snapshot into a VDI run:
  

  VBoxManage clonehd /full/path/to/{uuid-of-last-snapshot}.vdi thedisk-full.vdi
  

So I should clonehd only the last snapshot, not every snapshot from the chain. And it is thousands percent faster.

Resources¶

• https://www.virtualbox.org/manual/ch08.html