PARIS — OpenStack, the open-source, private-cloud answer to Amazon Web Services and other public clouds, is growing fast. You don't have to take my word for it. Just ask BMW, GoDaddy, Wells-Fargo, ...

OpenStack, the build-your-own-cloud software adopted as a flagship product by Red Hat, Canonical, and others, has long been seen as difficult to set up and manage. Now IBM (by way of its Softlayer ...