Extract the VMDK file with the -z flag to ensure tar uses compression to do so.

Author: mvousden

jobs/hook_vm.yml

@@ -69,7 +69,7 @@
   when: (not vagrantfile.stat.exists) and (not box_status.stat.exists or (box_status.stat.isreg and clobber_output))
 
 - name: Extract the virtual machine disk (VMDK) file from the box.
-  command: tar -xvf {{ output_box }} -C {{ artefact_dir }} ./box-disk1.vmdk
+  command: tar -xzvf {{ output_box }} -C {{ artefact_dir }} ./box-disk1.vmdk
     chdir={{ artefact_dir }}
     creates={{ artefact_dir }}/box-disk1.vmdk
   when: not zip_status.stat.exists or (zip_status.stat.isreg and clobber_output)