"What exactly is Puppet selling that VMWare wants"
Maybe I can help here, as I recall having conversations with both VMware and Puppet Labs about how both of them should get quite buddy buddy, so the chances are at least some of my arguments hold.
Puppet provides the ability to provision heterogenous environments. VMware is aware of a growing sense of paranoia amongst datacenter operators about getting locked into a single-vendor situation with regards to hypervisors + management tools, much as many fell victim to Microsoft. It is quite frankly something that VMware hears directly from partners and large customers, and is the number one reason for Hyper-V uptake in enterprise datacenters. Diversity equals bargaining power, and Puppet provides some of the best tools for ensuring that diversity.
More to the point, Puppet is focused on Openstack/Cloudstack, with passable (but limited) Microsoft anything support. VMware is quite okay competing with these open source alternatives, as VMware – despite the gnashing of teeth every time I use the term – is quite perfectly aware that the hypervisor has become commoditised. VMware believes strongly that their value proposition is their management tools, and third party ecosystem/integration. They believe they can compete against "free" by creating something easier to use, more convenient and better at automation. I believe they are 10% correct in this assessment.
Puppet is exploding. Like Spiceworks, it has a rapidly expanding community and uptake doesn't look set to stop. If VMware can get Puppet to be a great tool for Openstack, Cloudstack and VMware, with Microsoft's support lagging behind, then individuals and organisations seeking heterogenous support through Puppet will be turning to the open source alternatives and not Microsoft. VMware can have a voice in the development of these opensource projects. Microsoft is a true threat, if it starts seeing real adoption.
Beyond this, lots of companies still run physical equipment. VMware is big on the idea of managing things as a "single pane of glass." Puppet already manages devices that VMware doesn't have the ability to manage. The two companies combined could give you control over your entire datacenter; storage, networking, virtualisation stack, operating systems, applications, hybrid-cloud migration, cloud services provisioning, inventory and asset tracking and more.
Combined, Puppet and VMware would be very – very – close to being able to take on Microsoft's entire System Center suite of products. In fact, I'd argue that they need a good discovery package, mobile device management suite, a backup suite and an anti-malware suite and they're done. They could pip Microsoft by adding a simulation tool.
Now, interestingly, I have been working with a group of companies over the past six months that may well be able to come together to provide this. Consider Spiceworks; they offer network discovery and (very soon) mobile device management. Unitrends is a contender for the top enterprise-class backup startup and CloudPhysics is a simulation company with strong VMware ties that I personally believe will completely change the way we collectively approach network design, provisioning and even root cause analysis of errors. Toss Zenoss in there for a great monitoring package, and I'd buy that stack over Microsoft any day.
I've been busting my ass for 6 months to get as many of these folks in the same room as possible. (In fact, I'm in San Francisco next week as part of said mission.) I can't tell you how happy I am that VMware and Puppet managed to get all cozy; deep VMware integration has been something I've wanted out of Puppet for ages.
I abhor Microsoft's byzantine – and frankly batshit insane – licensing. I'm also tired of Microsoft's "just wait until the next service pack" bullshit on getting fixes (or what I would consider mandatory features) integrated into their products…only to have that "service pack" become yet another product that I have to license one more time at the cost of $way_too_much.
If we can get a third-party alliance set up of third-party vendors, then we might finally, mercifully see a price and innovation war occur in the enterprise management space. Something that hasn’t' really happened yet. Symantec can see it coming. That's part of why they want to divest themselves of Altiris. They know damned well they can't go toe-to-toe with Microsoft, VMware and Dell in an all out fight for dominance.
As to why VMware is choosing Puppet over Chef, I can answer that for you too. Chef is a very "script-heavy" offering. It is really a developers tool for controlling equipment and environments. Puppet can use scripts…but that's not remotely its focus. Puppet is about creating known-good states, and then enforcing the state. You set up a "state" for an operating system or system, and puppet handles whatever needs to be handled to ensure that state is set, or it screams at you that it can't.
Chef relies on the script writer to know his stuff, do a lot of testing and then deploy live. It is very much an extension of the traditional, plodding, "fortress IT" style practice of systems administration that marked the Unix era.
The entire ethos of Puppet – define a state and enforce it – fits very neatly into VMware's vision of the software defined, dynamic datacenter. Puppet is about trusting the tool to abstract the details of administration away. VMware is about automating your datacenter such that a smaller number of sysadmins can accomplish more. Fast, dynamic, every changing.
Chef works well in a world where you only need to make changes to your software or deployed applications once or twice a year. Puppet – and VMware – envision a world where change is a part of daily life; as natural as breathing.
So what does Puppet offer VMware? Rather a lot I'd say.