Why are Docker containers preferred over virtual machines?

Why are Docker containers preferred over virtual machines?

• A. They require more storage
• B. They have heavier startup times
• C. They are faster to deploy and consume less system resources
• D. They provide stronger isolation

Answer: (C)

Containers are lightweight because they use OS-level virtualization, running as isolated processes on the host OS and sharing the same kernel rather than booting a separate operating system for each instance. This design eliminates the overhead of starting and maintaining a full guest OS, so containers can be launched almost instantly and consume far fewer resources such as memory and CPU overhead. That combination—fast deployment and lower resource usage—is what makes containers preferable in many scenarios. The other statements don’t fit this picture. They do not require more storage; in fact, containers can share base image layers to save space. They also don’t have heavier startup times; they start much faster than virtual machines. And while containers provide strong process isolation via namespaces and cgroups, they do not offer as strong isolation as virtual machines, which rely on separate hardware virtualization.

Containers are lightweight because they use OS-level virtualization, running as isolated processes on the host OS and sharing the same kernel rather than booting a separate operating system for each instance. This design eliminates the overhead of starting and maintaining a full guest OS, so containers can be launched almost instantly and consume far fewer resources such as memory and CPU overhead. That combination—fast deployment and lower resource usage—is what makes containers preferable in many scenarios.

The other statements don’t fit this picture. They do not require more storage; in fact, containers can share base image layers to save space. They also don’t have heavier startup times; they start much faster than virtual machines. And while containers provide strong process isolation via namespaces and cgroups, they do not offer as strong isolation as virtual machines, which rely on separate hardware virtualization.