Start using the Ubuntu environment for your content by setting the imageid to ubuntu:1804.

For example:

"backend": {
  "imageid": "ubuntu:1804"

Looking for Ubuntu 20.04? Use the imageid ubuntu:2004

Ubuntu 18.04 Instance

Step 1

The Katacoda Ubuntu Environment is a flexible single node environment. Users are connected to the environment as root. This provides them with full flexibility to install additional packages, explore the internals of Linux and experiment with new ideas.

The environment also comes with Docker, meaning additional containers can be pulled and access as and when required.