User Space

When running your app "in the cloud" there is a dizzying layer of software controlling your trivially deployed code. In practice, it is your code → language VM → LXC Container → Linux OS → Xen Hypervisor → Linux OS → CPU.

Here we can look at each layer as a "user space," an expressive place that you are empowered to use, and a "kernel," the black box system that imposes strict constraints through an API.

By studying each layer in this way, we see self-similar properties, which offers insight for how to best participate in the ecosystem. We also understand why the cloud is built this way with the huge benefits in power and efficiency this offers to application developers.

Noah Zoschke is a lead engineer at Heroku, a cloud Platform-as-a-Service. He spends his time managing a team of infrastructure and systems engineers on the Heroku Runtime, a distributed code compilation, process management and process execution system responsible for running and scaling millions of applications.