Performance Comparison of Containers on Bare Metal versus Virtual Machines

Recent research shows Docker adoption in enterprises has surged from 13% in 2015 to over 65%, with 35% of companies planning to adopt it, driven by the need for faster development cycles and the role of containers in micro‑service architectures.

Despite these advantages, the question arises whether containers will replace virtual machines (VMs) or run directly on bare metal. The article argues that large enterprises should maintain a mix of virtualized servers, bare‑metal hosts, and containers.

Test results demonstrate that running containerized workloads on bare metal yields noticeably higher performance than on VMs. The article discusses the benefits and trade‑offs of both approaches.

Benefits of Containers

Containers provide a lightweight alternative to VMs by isolating applications with only the necessary runtime components, sharing the host OS kernel, and enabling consistent development environments, CI/CD pipelines, and stateless designs.

In contrast, VMs incur overhead because each guest OS must be fully replicated, leading to higher memory usage and slower provisioning.

To explore these differences, the authors conducted benchmarks on an Amazon EC2 m4.2xlarge instance (32 GB RAM, 8 vCPU) and a comparable bare‑metal server (Intel Core i7‑3770, 3.40 GHz, 32 GB RAM, SSD).

The container benchmark was executed with the following command:

docker run -d -m 256m -name=container-benchmark-vm simple-container-benchmarks

Results showed that bare‑metal containers outperformed VM‑based containers by 25%–30% for both file‑system and CPU operations. For example, file‑system copy rates were ~165 MB/s on bare metal versus ~125 MB/s on VMs, and CPU‑bound copy speeds were 19 MB/s versus 13 MB/s.

VM Benchmark Results

On VMs, file‑system write performance averaged around 127 MB/s, and CPU copy performance hovered near 12.8 MB/s.

Bare‑Metal Benchmark Results

On bare metal, file‑system write performance reached up to 168 MB/s, and CPU copy performance improved to about 19.5 MB/s.

Additional tests comparing Docker containers on bare metal versus VMs reported performance differences of 7×–9× in favor of bare metal.

Kubernetes on Bare Metal vs. VMs

Another benchmark by CenturyLink measured network latency using netperf‑tester for Kubernetes clusters deployed on bare‑metal servers versus VMs. The results showed roughly a three‑fold reduction in latency on bare metal, though CPU utilization could be higher in some VM scenarios.

The article concludes that workloads requiring direct hardware access—such as enterprise databases, compute‑intensive applications, analytics, BI processes, and machine‑learning model training—benefit significantly from bare‑metal deployment, while hybrid environments that combine containers and VMs provide flexibility for most organizations.

Finally, it advises IT teams to adopt cloud solutions that support both containers and VMs, enabling seamless hybrid cloud architectures that bridge on‑premises and public‑cloud resources.