  Context: Virtual machines provide isolation of services at the cost of
hypervisors and more resource usage. This spurred the growth of systems like
Docker that enable single hosts to isolate several applications, similar to
VMs, within a low-overhead abstraction called containers.
  Motivation: Although containers tout low overhead performance, do they still
have low energy consumption?
  Methodology: This work statistically compares ($t$-test, Wilcoxon) the energy
consumption of three application workloads in Docker and on bare-metal Linux.
  Results: In all cases, there was a statistically significant ($t$-test and
Wilcoxon $p < 0.05$) increase in energy consumption when running tests in
Docker, mostly due to the performance of I/O system calls.
