Containers or Virtual Machines?
What is the actual difference between a container and a virtual machine, and when would you still choose a VM?
Practical scenario
A team runs one JVM service per VM, 40 VMs, each at 8% CPU, and a deploy takes 11 minutes because every instance reboots. They ask whether containers would help — and the same platform also has to run customer-uploaded data transforms.
What it tests
Answer it out loud first. The guide below stays closed until you ask for it, on purpose.
- Whether the candidate knows containers share the host kernel and VMs do not
- Whether isolation strength is treated as a requirement rather than a detail
- Whether startup time and density are connected to a real operational consequence
Reading a strong answer is not the same as producing one. Commit to what you would say, then compare.