As an extension of what we are already asking people for, knowledge of VMware, VBox, Citrix Xen, etc. here will be a requirement to understand the various "cloud" platforms.
For example HOW to create and manage an AWS instance, DO Droplet, etc. (regardless of the OS running on the instance) as well as being able to manage those "guest" OS's.
More emphasis may be placed on infrastructure design, making use of clustering, load balancing, CDN usage, website "layer" splitting, etc., what they are and when to use them for the best website delivery "experience".