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About the test:

The Docker test uses scenario-based MCQs to evaluate candidates on their proficiency in working with Docker containers, their knowledge of Docker architecture, Docker command-line interface, Dockerfile syntax, Docker networking, Docker volumes, and Docker Compose. These key skills/topics are important for evaluating a candidate's ability to deploy and manage applications using Docker.

Covered skills:

  • Docker basics
  • Docker containers
  • Docker volumes
  • Docker swarm
  • Docker orchestration
  • Docker images
  • Docker networking
  • Docker compose
  • Docker security
  • Docker troubleshooting

9 reasons why
9 reasons why

Adaface Docker Test is the most accurate way to shortlist Docker Developers

Reason #1

Tests for on-the-job skills

The Docker Online Test helps recruiters and hiring managers identify qualified candidates from a pool of resumes, and helps in taking objective hiring decisions. It reduces the administrative overhead of interviewing too many candidates and saves time by filtering out unqualified candidates at the first step of the hiring process.

The test screens for the following skills that hiring managers look for in candidates:

  • Ability to understand and explain the basics of Docker
  • Ability to create, manage, and customize Docker images
  • Ability to launch, manage, and troubleshoot Docker containers
  • Ability to configure and manage Docker networking
  • Ability to work with Docker volumes and data persistence
  • Ability to use Docker Compose for multi-container applications
  • Ability to deploy and manage services using Docker Swarm
  • Ability to implement security measures in Docker environment
  • Ability to understand and implement Docker orchestration
  • Ability to troubleshoot common issues in Docker environment
Reason #2

No trick questions

no trick questions

Traditional assessment tools use trick questions and puzzles for the screening, which creates a lot of frustration among candidates about having to go through irrelevant screening assessments.

View sample questions

The main reason we started Adaface is that traditional pre-employment assessment platforms are not a fair way for companies to evaluate candidates. At Adaface, our mission is to help companies find great candidates by assessing on-the-job skills required for a role.

Why we started Adaface
Reason #3

Non-googleable questions

We have a very high focus on the quality of questions that test for on-the-job skills. Every question is non-googleable and we have a very high bar for the level of subject matter experts we onboard to create these questions. We have crawlers to check if any of the questions are leaked online. If/ when a question gets leaked, we get an alert. We change the question for you & let you know.

How we design questions

These are just a small sample from our library of 10,000+ questions. The actual questions on this Docker Test will be non-googleable.

🧐 Question


Docker Multistage Build Analysis
Multistage Builds
Consider the following Dockerfile, which utilizes multistage builds. The aim is to build a lightweight, optimized image that just runs the application.
The Dockerfile first defines a base image that includes Node.js and npm, then it creates an intermediate image to install the npm dependencies. Afterwards, it runs the tests in another stage and finally, creates the release image.

Which of the following statements are true?

A: The final image will include the test scripts.
B: If a test fails, the final image will not be created.
C: The node_modules directory in the final image comes from the base image.
D: The final image will only contain the necessary application files and dependencies.
E: If the application's source code changes, only the release stage needs to be rebuilt.


Docker Networking and Volume Mounting Interplay
Volume Mounting
You have two docker containers, X and Y. Container X is running a web service listening on port 8080, and container Y is supposed to consume this service. Both containers are created from images that don't have any special network configurations.

Container X has a Dockerfile as follows:
And, you build and run it with the following commands:
Container Y is also running alpine with python installed, and it's supposed to read data from the `/app/data` directory and send a GET request to `http://localhost:8080` every 5 minutes. The Dockerfile for container B is:
And you run it with:
Assuming all the python scripts work perfectly and firewall isn't blocking any connections, you find that container Y can't access the web service of container X via `http://localhost:8080` and also it can't read the data in `/app/data` directory. What could be the potential reason(s)?
A: Y can't access X's web service because they're in different Docker networks.
B: Y can't read the data because the volume is not shared correctly.
C: Both A and B are correct.
D: Both A and B are incorrect.


Dockerfile Optimization
Multi-stage builds
Layer Caching
You have been asked to optimize a Dockerfile for a Python application that involves a heavy dependency installation. Here is the Dockerfile you are starting with:
Given that the application's source code changes frequently but the dependencies listed in requirements.txt rarely change, how can you optimize this Dockerfile to take advantage of Docker's layer caching, reducing the build time?
A: Move the `RUN pip install` command to before the `COPY` command.
B: Change `COPY . /app` to `COPY ./ /app` and move the `RUN pip install` command to before the `COPY` command.
C: Add `RUN pip cache purge` before `RUN pip install`.
D: Replace the base image with `python:3.8-slim`.
E: Implement multi-stage builds.


Dockerfile Updates
Check the following Dockerfile used for a project (STAGE 1):
We created an image from this Dockerfile on Dec 14 2021. A couple of weeks after Dec 14 2021, Ubuntu released new security updates to their repository. After 2 months, we modified the file (STAGE 2):
Couple of weeks later, we further modified the file to add a local file ada.txt to /ada.txt (STAGE 3): (Note that ada.txt exists in /home/adaface and the dockerfile exists in /home/code folders)
Pick correct statements:

A: If we run “docker build .” at STAGE 2, new Ubuntu updates will be fetched because apt-get update will be run again since cache is invalidated for all lines/layers of Dockerfile when a new line is added.
B: If we run “docker build .” at STAGE 2, new Ubuntu updates will not be fetched since cache is invalidated only for last two lines of the updated Dockerfile. Since the first two commands remain the same, cached layers are re-used skipping apt get update.
C: To skip Cache, “docker build -no-cache .” can be used at STAGE 2. This will ensure new Ubuntu updates are picked up.
D: Docker command “docker build .” at STAGE 3 works as expected and adds local file ada.txt to the image.
E: Docker command “docker build .” at STAGE 3 gives an error “no such file or directory” since /home/adaface/ada.txt is not part of the Dockerfile context.


Efficient Dockerfile
Review the following Dockerfiles that work on two projects (project and project2):
All Docker files have the same end result:

- ‘project’ is cloned from git. After running few commands, ‘project’ code is removed.
- ‘project2’ is copied from file system and permissions to the folder is changed.
Pick the correct statements:

A: File 1 is the most efficient of all.
B: File 2 is the most efficient of all.
C: File 3 is the most efficient of all.
D: File 4 is the most efficient of all.
E: Merging multiple RUN commands into a single RUN command is efficient for ‘project’ since each RUN command creates a new layer with changed files and folders. Deleting files with RUN only marks these files as deleted but does not reclaim disk space. 
F: Copying ‘project2’ files and changing ownership in two separate commands will result in two layers since Docker duplicates all the files twice.
🧐 Question🔧 Skill


Docker Multistage Build Analysis
Multistage Builds

3 mins



Docker Networking and Volume Mounting Interplay
Volume Mounting

3 mins



Dockerfile Optimization
Multi-stage builds
Layer Caching

2 mins



Dockerfile Updates

2 mins



Efficient Dockerfile

2 mins

🧐 Question🔧 Skill💪 Difficulty⌛ Time
Docker Multistage Build Analysis
Multistage Builds
Medium3 mins
Docker Networking and Volume Mounting Interplay
Volume Mounting
Easy3 mins
Dockerfile Optimization
Multi-stage builds
Layer Caching
Medium2 mins
Dockerfile Updates
Medium2 mins
Efficient Dockerfile
Medium2 mins
Reason #4

1200+ customers in 75 countries

customers in 75 countries

With Adaface, we were able to optimise our initial screening process by upwards of 75%, freeing up precious time for both hiring managers and our talent acquisition team alike!

Brandon Lee, Head of People, Love, Bonito

Reason #5

Designed for elimination, not selection

The most important thing while implementing the pre-employment Docker Test in your hiring process is that it is an elimination tool, not a selection tool. In other words: you want to use the test to eliminate the candidates who do poorly on the test, not to select the candidates who come out at the top. While they are super valuable, pre-employment tests do not paint the entire picture of a candidate’s abilities, knowledge, and motivations. Multiple easy questions are more predictive of a candidate's ability than fewer hard questions. Harder questions are often "trick" based questions, which do not provide any meaningful signal about the candidate's skillset.

Science behind Adaface tests
Reason #6

1 click candidate invites

Email invites: You can send candidates an email invite to the Docker Test from your dashboard by entering their email address.

Public link: You can create a public link for each test that you can share with candidates.

API or integrations: You can invite candidates directly from your ATS by using our pre-built integrations with popular ATS systems or building a custom integration with your in-house ATS.

invite candidates
Reason #7

Detailed scorecards & benchmarks

View sample scorecard
Reason #8

High completion rate

Adaface tests are conversational, low-stress, and take just 25-40 mins to complete.

This is why Adaface has the highest test-completion rate (86%), which is more than 2x better than traditional assessments.

test completion rate
Reason #9

Advanced Proctoring

Learn more

About the Docker Assessment Test

Why you should use Pre-employment Docker Online Test?

The Docker Test makes use of scenario-based questions to test for on-the-job skills as opposed to theoretical knowledge, ensuring that candidates who do well on this screening test have the relavant skills. The questions are designed to covered following on-the-job aspects:

  • Understanding Docker basics and concepts
  • Creating, managing and deploying Docker images
  • Working with Docker containers and their lifecycle
  • Understanding Docker networking and communication between containers
  • Managing Docker volumes and persistent data
  • Working with Docker Compose to define and manage multi-container applications
  • Deploying and managing services using Docker Swarm
  • Implementing Docker security practices and policies
  • Orchestrating Docker containers for large-scale deployments

Once the test is sent to a candidate, the candidate receives a link in email to take the test. For each candidate, you will receive a detailed report with skills breakdown and benchmarks to shortlist the top candidates from your pool.

What topics are covered in the Docker Online Test?

  • Docker basics

    Docker basics include understanding the fundamental concepts and components of Docker, such as images, containers, and the Docker daemon. It is important to measure this skill in the test to assess the candidate's knowledge and familiarity with Docker as a containerization technology.

  • Docker images

    Docker images are the building blocks of containers, containing everything needed to run an application. This skill should be measured to evaluate the candidate's understanding of image creation, version control, and distribution, which are crucial for efficient and reliable container deployments.

  • Docker containers

    Docker containers are lightweight, isolated environments that run applications. Measuring this skill helps assess the candidate's ability to manage and configure containers, including network and storage settings, as well as their knowledge of containerization principles and best practices.

  • Docker networking

    Docker networking involves creating and managing network connections between containers and other resources. Testing this skill allows the recruiter to gauge the candidate's proficiency in configuring and troubleshooting Docker networks, understanding network modes, and implementing DNS and load balancing in containerized environments.

  • Docker volumes

    Docker volumes provide persistent storage for containers, allowing data to be stored and shared between different container instances. Evaluating this skill helps determine the candidate's knowledge of volume management, data persistence strategies, and how to handle filesystem permissions and ownership within containers.

  • Docker compose

    Docker Compose is a tool for defining and running multi-container applications. Measuring this skill is essential in assessing the candidate's ability to write and deploy Docker Compose files, which define the services, networks, and volumes required for complex containerized applications.

  • Docker swarm

    Docker Swarm is a native clustering and orchestration solution for Docker. Testing this skill evaluates the candidate's understanding of swarm mode, including creating and managing swarm clusters, deploying services, and scaling applications across multiple Docker nodes for high availability.

  • Docker security

    Docker security focuses on implementing best practices and features to secure Docker environments and containerized applications. Measuring this skill helps gauge the candidate's knowledge of Docker security mechanisms, such as user namespaces, image scanning, container isolation, network security, and vulnerability management.

  • Docker orchestration

    Docker orchestration involves managing and coordinating multiple Docker containers and services in a distributed environment. Evaluating this skill allows recruiters to determine the candidate's familiarity with Docker orchestration tools like Kubernetes or Docker Swarm, as well as their ability to configure and monitor containerized applications at scale.

  • Docker troubleshooting

    Docker troubleshooting entails identifying and resolving issues that may arise in Docker environments, such as container misconfigurations, networking problems, or performance bottlenecks. Measuring this skill helps assess the candidate's ability to effectively diagnose and troubleshoot problems in containerized applications, ensuring smooth and reliable operations.

  • Full list of covered topics

    The actual topics of the questions in the final test will depend on your job description and requirements. However, here's a list of topics you can expect the questions for Docker Test to be based on.

    Docker installation
    Docker architecture
    Docker image layers
    Docker container lifecycle
    Docker networking modes
    Docker volume management
    Docker Compose YAML syntax
    Docker Swarm setup and configuration
    Docker service scaling
    Docker security best practices
    Docker orchestration tools
    Docker troubleshooting techniques
    Docker CLI commands
    Docker registry
    Docker container logs
    Docker container environment variables
    Docker container health checks
    Docker container resource management
    Docker container intercommunication
    Docker image tagging and versioning
    Docker image optimization techniques
    Docker network configurations
    Docker volume backup and restore
    Docker Compose environment variables
    Docker Swarm service discovery
    Docker Swarm node management
    Docker security scanning
    Docker orchestration patterns
    Docker troubleshooting tools
    Docker command line options
    Docker image caching
    Docker container startup options
    Docker container environment isolation
    Docker image registry authentication
    Docker network routing
    Docker volume permissions
    Docker Compose deployment strategies
    Docker Swarm load balancing
    Docker security auditing
    Docker container resource monitoring
    Docker image layers optimization
    Docker network overlays
    Docker volume drivers
    Docker Compose scaling
    Docker Swarm service updates
    Docker security policies
    Docker orchestration rollback
    Docker container log management
    Docker container networking troubleshooting
    Docker image vulnerability scanning
    Docker Compose network configuration
    Docker Swarm health checks
    Docker security hardening
    Docker container process monitoring
    Docker image size reduction
    Docker network firewall settings
    Docker volume backup strategies
    Docker Compose service discovery
    Docker Swarm service constraints
    Docker security compliance
    Docker container performance optimization
    Docker image layer caching
    Docker network load balancing
    Docker volume encryption
    Docker Compose volume management
    Docker Swarm secret management
    Docker security vulnerabilities
    Docker container high availability
    Docker image versioning strategies
    Docker network traffic control
    Docker volume replication
    Docker Compose environment variable substitution
    Docker Swarm stack deployment
    Docker security auditing tools
    Docker container resource isolation
    Docker image storage optimization
    Docker network DNS resolution
    Docker volume size management
    Docker Compose service scalability
    Docker Swarm multi-manager setup
    Docker security incident response
    Docker container log rotation
    Docker image source control integration
    Docker network latency optimization
    Docker volume performance tuning
    Docker Compose dependency management
    Docker Swarm service rolling updates
    Docker security compliance scanning
    Docker container debug logging
    Docker image multi-arch support
    Docker network gateway configuration
    Docker volume snapshotting
    Docker Compose container linking
    Docker Swarm multi-cluster setup
    Docker security access control
    Docker container log aggregation
    Docker image artifact management

What roles can I use the Docker Online Test for?

  • Docker Developer
  • DevOps Engineer
  • Site Reliability Engineer
  • Infrastructure Engineer
  • Containerization Specialist
  • Backend Developer

How is the Docker Online Test customized for senior candidates?

For intermediate/ experienced candidates, we customize the assessment questions to include advanced topics and increase the difficulty level of the questions. This might include adding questions on topics like

  • Designing and implementing Docker infrastructure
  • Building resilient and scalable Docker architecture
  • Implementing container orchestration with Kubernetes and Docker
  • Integrating Docker with CI/CD pipelines
  • Managing Docker in cloud environments
  • Monitoring and logging Docker containers and applications
  • Implementing high availability and fault tolerance in Docker deployments
  • Automating Docker tasks using scripting and automation tools
  • Performing Docker image optimization and size reduction
  • Configuring and managing advanced Docker networking
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The hiring managers felt that through the technical questions that they asked during the panel interviews, they were able to tell which candidates had better scores, and differentiated with those who did not score as well. They are highly satisfied with the quality of candidates shortlisted with the Adaface screening.

reduction in screening time

Docker Hiring Test FAQs

Can I combine multiple skills into one custom assessment?

Yes, absolutely. Custom assessments are set up based on your job description, and will include questions on all must-have skills you specify. Here's a quick guide on how you can request a custom test.

Do you have any anti-cheating or proctoring features in place?

We have the following anti-cheating features in place:

  • Non-googleable questions
  • IP proctoring
  • Screen proctoring
  • Web proctoring
  • Webcam proctoring
  • Plagiarism detection
  • Secure browser
  • Copy paste protection

Read more about the proctoring features.

How do I interpret test scores?

The primary thing to keep in mind is that an assessment is an elimination tool, not a selection tool. A skills assessment is optimized to help you eliminate candidates who are not technically qualified for the role, it is not optimized to help you find the best candidate for the role. So the ideal way to use an assessment is to decide a threshold score (typically 55%, we help you benchmark) and invite all candidates who score above the threshold for the next rounds of interview.

What experience level can I use this test for?

Each Adaface assessment is customized to your job description/ ideal candidate persona (our subject matter experts will pick the right questions for your assessment from our library of 10000+ questions). This assessment can be customized for any experience level.

Does every candidate get the same questions?

Yes, it makes it much easier for you to compare candidates. Options for MCQ questions and the order of questions are randomized. We have anti-cheating/ proctoring features in place. In our enterprise plan, we also have the option to create multiple versions of the same assessment with questions of similar difficulty levels.

I'm a candidate. Can I try a practice test?

No. Unfortunately, we do not support practice tests at the moment. However, you can use our sample questions for practice.

What is the cost of using this test?

You can check out our pricing plans.

Can I get a free trial?

Yes, you can sign up for free and preview this test.

I just moved to a paid plan. How can I request a custom assessment?

Here is a quick guide on how to request a custom assessment on Adaface.

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40 min tests.
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