Gillis joined VMware in May 2018 by way of the acquisition of his company Bracket Computing, which was developing cloud workload protection and isolation technology. The former Bracket Computing technology has now largely been integrated with VMware's networking and security stack, providing additional capabilities for organizations to protect workloads. Both VMware and Bracket Computing have been pursuing an approach of tag-based policy enforcement. He explained that with a tag-based approach, simple human understandable policies for security can be easily defined. For example, a policy can be set up that states a web server can talk to an application server and a database server, but nothing else.