Microsoft and Docker today announced a new joint open-source project, the Cloud Native Application Bundle (CNAB), that aims to make the lifecycle management of cloud-native applications easier. At its core, the CNAB is nothing but a specification that allows developers to declare how an application should be packaged and run. With this, developers can define their resources and then deploy the application to anything from their local workstation to public clouds.

The specification was born inside Microsoft, but as the team talked to Docker, it turns out that the engineers there were working on a similar project. The two decided to combine forces and launch the result as a single open-source project. “About a year ago, we realized we’re both working on the same thing,” Microsoft’s Gabe Monroy told me. “We decided to combine forces and bring it together as an industry standard.”

As part of this, Microsoft is launching its own reference implementation of a CNAB client today. Duffle, as it’s called, allows users to perform all the usual lifecycle steps (install, upgrade, uninstall), create new CNAB bundles and sign them cryptographically. Docker is working on integrating CNAB into its own tools, too.

Microsoft also today launched Visual Studio extension for building and hosting these bundles, as well as an example implementation of a bundle repository server and an Electron installer that lets you install a bundle with the help of a GUI.

Now it’s worth noting that we’re talking about a specification and reference implementations here. There is obviously a huge ecosystem of lifecycle management tools on the market today that all have their own strengths and weaknesses. “We’re not going to be able to unify that tooling,” said Monroy. “I don’t think that’s a feasible goal. But what we can do is we can unify the model around it, specifically the lifecycle management experience as well as the packaging and distribution experience. That’s effectively what Docker has been able to do with the single-workload case.”

Over time, Microsoft and Docker would like for the specification to end up in a vendor-neutral foundation. Which one remains to be seen, though the Open Container Initiative seems like the natural home for a project like this.