Gone are the days of isolation, in today’s world, everything is connected to everything which makes networking and security very important.

In order to become a good DevOps engineer, you must know about basic networking

This is probably the most important thing for a DevOps engineer and this is a very vast area as well.

As a DevOps engineer, you should know about containers like

Apart from setup and deployment, monitoring is another important aspect of DevOps and that’s why it’s important for a DevOps engineer to learn about Infrastructure and application

As a DevOps champion, you should know what is set up in your machine and how you can set that up, only that you can think about automating it.

In general, a DevOps engineer should know how to set up a Web Server like IIS,

This is another very important thing for DevOps gurus and champion, i.e. to set up a pipeline for continuous integration and delivery. There are a lot of tools in the CI/CD area e.g.

For a DevOps, it's important to have good command in the command line. Knowing some Linux shell like Bash or Ksh and tools like find, grep, awk, sed, lsof, and networking commands like nslookup and netstat is mandatory. 

The three main programming languages are: Java, Python, and JavaScript. I strongly suggest that you learn at least one of the three major general purpose programming languages.

DevOps now requires developers to know about OS and hardware. 

You also need to know about process management, threads and Concurrency, Sockets, I/O Management, Virtualization, memory storage and file systems as suggested in roadmap.