Customer Voice

An Amazing Decade of Innovation

It’s been just over 10 years since the Flings program launched in 2010. The program — a site showcasing free experimental tools developed by VMware’s internal community (see — was the brainchild of a small group in the Office of the CTO (OCTO). While public domain, these tools are not officially supported in a production environment. When I was handed the program in 2011, there were just 10 Flings on a small WordPress site. Now, in 2021, the site hosts more than 200!

VMware engineers welcome feedback on their Flings. They update them with bug fixes and add new features. Additionally, the functionality of some Flings is implemented in VMware products.

Why Flings?

When I first inherited the program, I spoke with the Fling developers to wrap my head around the reasons why they were creating free tools for customers. The main answers I received were:

  • “I want to get feedback on the utility of a tool I created.”
  • “I haven’t yet been able to get this functionality/feature onto the product roadmap, so I wanted another place to develop it further.”
  • “I think this would be a cool feature, but there is internal resistance to implementing it.”

The one comment that made the biggest impression on me was from a manager in the Performance group, whose team had developed the I/O Analyzer Fling. She said, “We use this tool internally and find it incredibly useful, so we thought it would be great to share it with our customers because they’d also find it useful.” I asked her why, if it was so great, we wouldn’t turn it into a product. “Because we can develop trust by giving customers something really useful for free, and we benefit by encouraging them to stay engaged in our products.”

I/O Analyzer remained in the Top 10 Downloads from the time it was released in 2012, all the way through 2018. It continues to make an appearance on that list from time to time.

Overcoming resistance

A few months after I took over the Flings program, I met William Lam and Alan Renouf. They came to me with concerns about Flings, such as that customers might have trouble locating them, and that engineers wouldn’t want release their tools as Flings. Both William and Alan had been VMware customers before they were employees, and both had scripts and tools they knew customers would benefit from. William has a blog called Virtually Ghetto, where he hosts useful scripts and blogs for customers, as well as tales of his own personal lab, which he works on continuously. He thought that sites like his might be a more appropriate place to host this type of content. But after our discussion and over the years to follow, both produced some of the most popular Flings on the site:

They’ve been wonderful advocates of the program, both internally and externally, ever since.

One of our other prolific Fling developers is Chris Halstead. I didn’t meet Chris in person until 2017 at VMware’s internal conference, RADIO. He has released seven Flings – the last being App Volumes Entitlement Sync. He‘s got another in the works that will be released this year.

That same year, I met Nan Wang and his manager Sam Zhao from China. Nan was the developer of the VMware OS Optimization Tool, a Fling that’s been in the top three downloads since it was released in 2016. It’s often in the #1 spot! Nan and team have since created five Flings, all of which have been very popular with customers.

Gaining traction

We generally release between 20-35 new Flings a year, as well as approximately 55-90 updates to existing Flings. A worldwide pandemic made 2020 a rough year, so it wasn’t surprising that we only released 26 new Flings. That said, the Flings we did release were amazing.

VMware Appliance for Folding@Home was released in April (another William Lam Fling), and in the summer, we released VMware Container for Folding@Home from Ryan Kelly. Folding@home (FAH or F@h) is a distributed computing project for simulating protein dynamics, including the process of protein folding and the movements of proteins implicated in a variety of diseases. Both Flings provide benefits for working with the Folding@home client. It was exciting to be a part of the COVID-19 response.

Another Fling from last year we are excited about is the ESXi Arm Edition Fling. This Fling has 12 contributors — far more than most (which usually have three or less). This evaluation program is for enterprise architects considering the viability of virtualizing ARM workloads, test/dev teams looking for a way to spin up ARM environments, and tinkerers who simply want to explore running ESXi-ARM in a small-form-factor edge environment. They would love your feedback!

Over the years, we’ve had over a dozen Flings integrated into official VMware products. The first productized Fling was ViewDbChk, which was originally released in 2014. Some of the others were PowerCLI Extensions, PowerCLI Core, vSphere Content Library Assistant, vSphere HTML5 Web Client, and, at the end of December 2020, Cross vCenter Workload Migration Utility.

It’s all about the customers

We often have customers ask why their favorite Fling hasn’t been productized so that it would be supported in production. The answer is that you can influence this by suggesting it in the Fling’s Comments tab. Simply tell us how much you like the Fling and add any other details you’d like to share. Fling developers bring these comments to product teams, who take them seriously and consider adding them to the roadmap. Also, please take advantage of the Bug tab and report issues you encounter.  

I’m excited to share that we are starting 2021 with a fresh look and new features on In addition to implementing the Clarity Design System, you can now see the Flings you have downloaded in your profile. You’ll also see a tag when an update is released for those Flings. There are now 86 new updates to existing Flings, so please visit the new site and check to see if any Flings you’re using have been updated.

I want to thank all of you who have downloaded and reported on Flings you’ve used. You have helped make this program the success that it is. We love hearing from customers on the site in the comments, and on @vmwflings on Twitter.

Top 10 Flings Downloads of 2020

  1. VMware OS Optimization Tool: 53,517
  2. ESXi Arm Edition: 13,285
  3. VMware Appliance for Folding@Home:13,060
  4. USB Network Native Driver for ESXi: 11,336
  5. Cross vCenter Workload Migration Utility: 11,055 (productized)
  6. ESXi Embedded Host Client: 8,178 (productized)
  7. HCIBench: 7,878
  8. Vmss2core: 6,967
  9. vSphere HTML5 Web Client: 6,607 (productized)
  10. Horizon Helpdesk Utility: 4,917