VMWare Virtual Machine Backup

9/28/2008

Overview

I did this project as a contract job based on a need a customer had to replicate and backup their virtual machines. This software operates very similar to VMWare Consolidated Backup: Copy the VMDK files down to some other file store to be picked up by another backup software later on. Only this one takes it a step further, and actually replicates VMDK files to other hosts–such as a warm-standby. It is a really new project of mine and hasn’t been tested in production yet, but it will be pretty soon. Preliminary tests look promising, I hope to have it deployed into a production environment in about a month or so. So far it has taken around 30 hours to develop.

The requirements I had to work with were:

  • Had to be “hidden” from the end-customer. Meaning that the end-user couldn’t have any visibility into the operations of the software, it had to be compiled.
  • Could not interrupt Virtual Machines that are powered on and using their disks.
  • Had to scale with larger environments and work when the environment grows out of its current 3-host server infrastructure.

My solutions were:

  • Use C# as it is the only quasi-compiled API solution VMWare offered to communicate with ESX.
  • Use VMWare’s snapshot technology
  • Allow for any number of sources, any number of destinations, and any number of Virtual Machines. In theory as well, this software could be run from multiple backup servers to backup certain “subsets” or cluseters of ESX servers, so the strain isn’t concentrated on a single VMBackup server. It isn’t cluster-computing, but its a feasable option and easy to implement.

I wrote the documentation and did the diagrams as well. So as a whole, this project is pretty solid and I’m proud of it. I cannot offer downloads of the source code or the program itself however, at least not at this time. So pictures of the configuration utility and the user documentation will have to do.

Technology

This whole program is written in C#, using the VMWare communication API (VI SDK 2.5). So the technologies at work here are VMWare’s snapshot technology and good ol’ SOAP web services. C# was my solution to the “had to be compiled” requirement. Mainly because VMWare didn’t offer a C++ API, only C# and Perl. My strongpoint between the two is C#, so thats another reason why I chose it. The web services wasn’t really an option, thats how the VI SDK works, so I had to go with it. The snapshots were the solution to the problem where running VM’s can’t be backed up because there’s a lock on the VMDK file. It is an easy, and well known, solution to the problem.

Downloads

[download id="16,17"]

Screenshots

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