Virtual Disk API Programming Guide - Documentation - VMware

Virtual Disk Programming Guide
The data returned from the PropertyCollector is a container class called PropertyFilterUpdate, which
contains an objectSet with an item‐by‐item list of changes to object properties. Every item in this container
is identified with one of the following keys: enter (add), leave (delete), and modify. On the first data request,
every data item is included, and “enter” is marked for every data item.
The PropertyCollector presents its results in what amounts to random order. Since all managed objects
have a “parent” property, you can reconstruct the configuration hierarchy by building a tree in memory, using
the parent identification to organize. The root folder is identified as the only folder without a parent.
Useful Property Information
In the data returned from PropertyCollector, you can find most of the information that is useful for backup
in the Virtual Machine managed object, including the following:
Virtual Disks – names, types, and capacities.
Virtual Machine Type and Configuration – Whatever would be useful in (re)creating a virtual machine.
This list might include such information as memory size and number of CPUs.
Display Names – These names appear in VMware products such as the vSphere Client. You should keep
track of these names and correlate them for consistency between your product and VMware products.
VMware supports many virtual disk implementations. The disk implementation type is important because:
On restore, you should re‐create virtual disk with the same disk type as the original virtual machine used.
A disk backed by a pass‐through raw device mapping (RDM) mostly bypasses the ESXi storage stack. You
cannot make a snapshot of this virtual disk type. Therefore, you cannot back up pass‐through RDM disk
using the snapshot method described in this document.
For more information about the Java APIs, read the first several chapters of the VMware vSphere Web Services
SDK Programming Guide, and related pages of the Web‐based VMware vSphere API Reference Documentation.
Both are available at http://www.vmware.com/support/developer/vc‐sdk. Examples in this chapter assume
that you have set up the vSphere SDK as described in documentation.
Doing a Backup Operation
After your program obtains information about what is available to back up, it can perform a backup. The three
steps to the backup process are:
“Create a Temporary Snapshot on the Target Virtual Machine” on page 60
“Extract Backup Data from the Target Virtual Machine” on page 61, and save configuration information.
“Delete the Temporary Snapshot” on page 61
Prerequisites
To complete a backup, the calling program requires the permissions shown in Table 7‐1.
Table 7-1. Required Permissions to Complete a Backup
Privilege Category Privilege Subcategory Privilege
Virtual Machine Provisioning Allow Virtual Machine Download
State Create Snapshot
Remove Snapshot
Configuration Disk Lease
Create a Temporary Snapshot on the Target Virtual Machine
The low‐level procedure for creating a snapshot of a virtual machine is documented in the section “Creating
a Snapshot” on page 68. Set the quiesce flag True to make the file system quiescent, otherwise the snapshot
might represent a transitional system state, with inconsistent data. Restoring such data might be destructive.
60 VMware, Inc.