Containers Interview Questions
10 questions
Container fundamentals beyond any single runtime — image layering, isolation mechanisms, and the concepts that underpin Docker, containerd, and Kubernetes alike.
What's actually the difference between a container and a virtual machine, at the operating system level — not the marketing-slide version?
BeginnerContainersLinux7 min
How would you explain the security trade-off between containers and VMs to someone deciding whether to run untrusted third-party code?
IntermediateContainers6 min
Why does a container image being much smaller than a VM image matter for both startup time and attack surface, specifically?
BeginnerDockerContainers6 min
What specific Linux namespace types exist, and what does each one actually isolate for a containerized process?
IntermediateLinuxContainers7 min
What actually changed between cgroups v1 and v2, and why did some container resource limit behavior change when a host migrated to a v2-only kernel/distro?
AdvancedContainersLinux7 min
Kubernetes dropped direct Docker support years ago in favor of containerd/CRI-O. What's the actual relationship between Docker, containerd, and CRI-O, and why did this change happen?
IntermediateContainersKubernetes7 min
What does it actually mean for a container image to be 'OCI-compliant,' and why does that matter beyond just being a compatibility buzzword?
IntermediateContainers6 min
A container keeps getting killed, and both the container's own memory limit and the host's overall available memory look potentially responsible. How do you determine which one actually caused it?
AdvancedContainersLinux7 min
How does a container image's layered filesystem actually work at the OS level — what makes writes inside a running container not modify the underlying image?
IntermediateContainersLinux6 min
Your containerized application's process count keeps growing over time, even though nothing appears to be leaking connections or memory. What's likely happening, and why is it specific to running in a container?
AdvancedContainersLinux7 min