DCA Cheat Sheet 2026

The 30 highest-yield DCA facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. A security scan finds a critical CVE in a base image. What is the recommended remediation workflow in a Docker-based CI/CD pipeline? → Update the base image tag in the Dockerfile, rebuild, re-scan, and redeploy
2. How do regulations differ from industry standards in DCA practice? → Regulations are legally binding; standards are typically voluntary guidelines
3. A team member shares a Dockerfile that pulls a base image using 'latest' tag in production. What professional concern should be raised? → Using 'latest' reduces reproducibility and can introduce unexpected breaking changes
4. Why is written communication important in DCA practice? → It creates a permanent record, ensures clarity, and provides reference for future actions
5. A DevOps team needs to communicate service health to operations stakeholders. Which Docker Swarm feature provides built-in service health information? → Health checks defined in the service spec
6. Which Dockerfile instruction, when used incorrectly, most commonly leads to unnecessarily large image sizes that fail image size quality gates? → RUN (installing packages without cleaning up cache in the same layer)
7. To export Prometheus-compatible metrics from the Docker daemon, which configuration option must be enabled? → "experimental": true and "metrics-addr"
8. An organization's risk policy requires that no container run as UID 0. Which Dockerfile instruction enforces this at the image level? → USER nonroot
9. Why is regular review important in DCA risk management? → Because conditions change and new risks emerge requiring updated assessments
10. What is multi-factor authentication (MFA) in DCA security? → A security method requiring two or more verification factors to gain access
11. How can John launch a container that utilizes the json-file log driver when he has configured his Docker daemon to use the syslog log driver by default? → By using “--log-driver json-file” along with docker run
12. You need to time-limit `docker events` to only show events that occurred in a specific window. Which flags accomplish this? → --since and --until
13. Which of the following parameters would allow you to SSH into an active "nginx" Docker container? → docker exec -it nginx /bin/sh
14. Which command lists all nodes currently participating in a Docker Swarm? → docker node ls
15. During project planning, the security team requires all containers to run as a non-root user. How is this enforced in a Dockerfile? → USER instruction before the CMD or ENTRYPOINT
16. Which log driver is the default for Docker containers when no driver is explicitly configured? → json-file
17. A project stakeholder needs a summary of all running services and their replica counts in a Docker Swarm. Which command provides this? → docker service ls
18. PCI DSS Requirement 6 mandates secure development practices. Which Docker workflow directly addresses this for containerized applications? → Integrating image vulnerability scanning into the CI/CD pipeline before deployment
19. What does running a container with the `--privileged` flag do? → Grants the container almost all Linux capabilities and access to host devices
20. Which action best demonstrates professional responsibility when a Docker host shows signs of compromise? → Immediately isolate the host, preserve logs, and follow the incident response plan
21. What is trend analysis in DCA reporting? → Examining data over time to identify patterns, directions, and changes in performance
22. What is the default subnet used by Docker's default bridge network (docker0)? → 172.17.0.0/16
23. Which practice ensures Docker image build reproducibility, which is required for software supply chain compliance frameworks like SLSA? → Pinning base images to immutable digests (SHA256) in Dockerfiles
24. What is cash flow management in DCA practice? → Monitoring and optimizing the timing of money coming in and going out of an organization
25. What does the Apache 2.0 license require when distributing modified versions of Apache-licensed Docker components? → Include a NOTICE file and state significant changes made to the original
26. When planning secrets management for a Docker Swarm project, what is the correct way to create a secret from a file? → docker secret create my_secret ./secret.txt
27. Which `docker events` filter would show only container die events? → --filter type=container --filter event=die
28. A junior engineer checks in a Dockerfile with the instruction 'USER root' for all services. What is the professional responsibility of the reviewer? → Request that the engineer use a non-root user and explain the principle of least privilege
29. Which command shows detailed information about a Docker network including its connected containers? → docker network inspect my-network
30. Which Docker feature allows you to enforce mandatory access controls by restricting the system calls a container can make to the host kernel? → Seccomp profiles