Docker architecture (client, daemon, registry) - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Role of Docker Client in Docker Architecture

What is the primary role of the Docker Client in the Docker architecture?

A It acts as the user interface to send commands to the Docker Daemon.

B It manages and runs containers directly on the host system.

C It stores Docker images and makes them available for download.

D It builds Docker images from Dockerfiles automatically.

💡 Hint

Think about which part the user interacts with directly to control Docker.

The Docker Client is the command-line tool or API that users interact with. It sends commands to the Docker Daemon, which does the actual work of managing containers and images.

🧠 Conceptual

intermediate

Function of Docker Daemon

Which statement best describes the function of the Docker Daemon?

A It listens for Docker Client requests and manages Docker objects like images and containers.

B It stores Docker images in a cloud-based registry service.

C It provides a web interface for managing Docker containers remotely.

D It compiles Dockerfiles into executable binaries.

💡 Hint

Consider which component actually runs containers and handles Docker commands.

The Docker Daemon runs on the host machine and listens for commands from the Docker Client. It manages images, containers, networks, and storage volumes.

🧠 Conceptual

advanced

Purpose of Docker Registry

What is the main purpose of a Docker Registry in the Docker architecture?

A It manages network connections between Docker containers.

B It builds Docker images from source code automatically.

C It stores and distributes Docker images to clients and daemons.

D It monitors running containers and reports their status.

💡 Hint

Think about where Docker images are saved and shared from.

A Docker Registry is a storage and distribution system for Docker images. Public registries like Docker Hub or private registries allow users to push and pull images.

🔀 Workflow

advanced

Sequence of Docker Command Execution

Arrange the steps in the correct order when a user runs docker run command.

A 1,3,2,4

B 1,2,3,4

C 2,1,3,4

D 1,2,4,3

💡 Hint

Think about the logical order from command to container start.

First, the client sends the command. Then the daemon checks for the image locally. If missing, it pulls from the registry. Finally, it creates and starts the container.

❓ Troubleshoot

expert

Diagnosing Docker Client and Daemon Communication Issue

A user runs docker ps but gets the error: Cannot connect to the Docker daemon. What is the most likely cause?

A The container is stopped and cannot be listed.

B Docker Registry is down and cannot provide container images.

C Docker Client has an outdated version incompatible with the Daemon.

D Docker Daemon is not running or not reachable by the Docker Client.

💡 Hint

Consider what happens if the client cannot talk to the daemon.

The error means the Docker Client cannot reach the Docker Daemon. This usually happens if the daemon is stopped or there are permission/network issues.