OpenStack

OpenStack gives you a way to run your own public or private cloud without getting locked into a proprietary vendor. It started as a joint project from Rackspace and NASA back in 2010, and today it's managed by the Open Infrastructure Foundation. The platform is modular: you pick the services you need. Nova handles compute and virtual machine orchestration. Swift and Cinder provide object and block storage. Neutron takes care of networking and security groups. Glance manages VM images, and Keystone handles identity and access control. Over the years OpenStack has grown into a massive ecosystem used by telcos, research labs, and enterprises like Walmart and CERN. It runs on standard Linux distributions and supports hypervisors including KVM, VMware, and Hyper-V. Deployment can be tricky. Tools like TripleO, Kolla, and Puppet modules try to make it easier, but you still need real ops experience. The community releases new versions on a time-based cycle roughly every six months, named alphabetically. The latest stable release is Zed. If you need to build a multi-tenant infrastructure with bare metal, containers, and VMs all in one stack, OpenStack is the most mature option out there.