Container limits bound resources but do not replace application concurrency control. Memory exhaustion and CPU throttling have different symptoms.
Before you start
You should understand the difference between an image, a running container and the host. Record where a file, process or network endpoint actually lives before diagnosing a problem. Commands illustrate local experiments; adapt image names and paths to a disposable development environment.
The practical goal is to reason through this situation: A service with a memory limit still needs bounded request buffers and caches. Read the walkthrough first, then try the interview exercise before opening its answer. The important part is explaining the decision and its consequences, rather than remembering a definition alone.
Step-by-step walkthrough
Step 1: Measure the constrained resource
CPU throttling and memory exhaustion produce different symptoms.
Step 2: Bound application admission
Limits do not stop unlimited buffers, caches or queued requests from growing internally.
Step 3: Align capacity and limits
Use representative workload evidence rather than continually raising ceilings.
Worked scenario
A service with a memory limit still needs bounded request buffers and caches.
A service queues every incoming request while constrained to a small CPU budget. Latency rises from throttling and queue delay. Raising memory may postpone queue exhaustion but does not increase processing capacity; bounded admission and an explicit overload response address the workload mismatch.
Common mistake
Increasing a limit can hide unbounded growth rather than fix it.
Verify the behavior
Measure throttling, live memory, queue depth and latency during saturation.
Interview exercise
Diagnose latency under load.
Answer and reasoning
Check throttling, memory growth and queue depth, then align limits with measured workload and capacity.
Continue learning
Compare the scenario with the Docker interview questions and test your understanding with the Docker MCQs. For terminology and implementation details, consult the reference material.