Thanks to their excellent performance, unikernels have always had a great deal of potential for revolutionizing the efficiency of virtualization and cloud deployments. However, after many years and several projects, unikernels, for the most part, have not seen significant, real-world deployment. In this article we argue that several factors contributed to this in the past, including lack of POSIX compatibility and the resulting lack of support for applications and languages, difficult or not widely adopted tooling ecosystems, lack of basic security features, and sometimes less-than-stellar performance. After many years of work on the Linux Foundation's Unikraft project, whose explicit goal is to tackle these issues directly, we believe that the time for unikernels to finally enter the main stage is now
