Sample Questions from Docker Certified Associate (Phasing regionally) DCA

Preview a few questions below — answers are revealed when you take the exam.

1. A team needs to deploy a microservices architecture using Docker. They want to ensure that services can discover each other dynamically and scale horizontally. What approach should they take?

   • Utilize Docker Compose with a static configuration file for service discovery and scaling.
   • Implement a service mesh like Istio alongside Docker to handle dynamic service discovery and horizontal scaling.
   • Use Docker Swarm to manage service discovery and scaling, leveraging its built-in features for microservices.
   • Deploy each microservice in separate Docker containers and manually configure network settings for discovery and scaling.

2. Consider the situation where a Docker container frequently crashes due to memory leaks. Which method solves it best?

   • Increase the memory limit of the container using the --memory flag and monitor its usage over time.
   • Convert the container to a virtual machine to utilize more robust memory management features.
   • Implement a custom script to periodically restart the container when memory usage exceeds a threshold.
   • Use a third-party tool to analyze the container's memory usage and identify the source of the leak.

3. Identify the command used to remove all stopped containers, unused networks, and dangling images in Docker.

   • docker system prune
   • docker container rm
   • docker network prune
   • docker image rm

4. Which option best evaluates the security implications of running Docker containers with the --privileged flag?

   • It allows the container to access all host devices and capabilities, posing significant security risks.
   • It enhances container isolation, reducing the attack surface available to potential threats.
   • It limits the container's access to host resources, improving overall system security.
   • It has no impact on container security, as Docker manages all security aspects internally.

5. How should a professional assess the performance impact of using Docker volumes versus bind mounts for persistent storage?

   • Conduct performance tests under various workloads to compare the I/O performance and latency of both storage options.
   • Assume that Docker volumes always provide better performance due to their optimized design for container storage.
   • Rely on vendor documentation to determine the performance characteristics of each storage option.
   • Choose Docker volumes for all use cases, as they are the recommended storage solution for Docker containers.