  The current virtualization solution in the Cloud widely relies on
hypervisor-based technologies. Along with the recent popularity of Docker, the
container-based virtualization starts receiving more attention for being a
promising alternative. Since both of the virtualization solutions are not
resource-free, their performance overheads would lead to negative impacts on
the quality of Cloud services. To help fundamentally understand the performance
difference between these two types of virtualization solutions, we use a
physical machine with "just-enough" resource as a baseline to investigate the
performance overhead of a standalone Docker container against a standalone
virtual machine (VM). With findings contrary to the related work, our
evaluation results show that the virtualization's performance overhead could
vary not only on a feature-by-feature basis but also on a job-to-job basis.
Although the container-based solution is undoubtedly lightweight, the
hypervisor-based technology does not come with higher performance overhead in
every case. For example, Docker containers particularly exhibit lower QoS in
terms of storage transaction speed.
