[$] Docker and the OCI container ecosystem

Docker has transformed the waymany people develop and deploy software. It wasn't the firstimplementation of containers on Linux, but Docker's ideas about howcontainers should be structured and managed were different from itspredecessors. Those ideas matured into industry standards, and anecosystem of software has grown around them. Docker continues to be amajor player in the ecosystem, but it is no longer the only whale in thesea - Red Hat has also done a lot of work oncontainer tools, and alternative implementations arenow available for many of Docker's offerings.