Container Linux, formerly known as CoreOS, was developed in 2013 as a very small Linux distribution optimized as a host for running containers. They started with using Docker, but in 2014 they switched to their own container technology, Rkt, which is heavily dependent on systemd-nspawn. In January 2018, the company behind Container Linux was acquired by Red Hat.
While it is perfectly possible to install Rkt on other distributions (for more information, visit https://coreos.com/rkt/docs/latest/distributions.html), in this section I'm going to use Container Linux. You can simply deploy via the latest stable version via the Azure Portal or use the Azure CLI/PowerShell method.
In the Azure Marketplace, Container Linux is still available under the old name CoreOS at the time of writing. This will change in the near future.
