Updated March 4, 2023
Introduction to Docker Interview Questions and Answers
Docker is a form of containerization or virtualizing the operating system in the form of a computer code level. It was completely written in the Go programming language. It was licensed under Apache License 2.0 in binary form. It was first released in the year 2013. It was developed and is maintained by Docker Inc. Docker is used to running Containers which are called the process of encapsulating the applications and containerizing in the form of containers. It supports multiple operating systems such as Linux, Windows, Mac OS. It supports different platforms such as ARM architecture and x86-64 windows platforms. Docker was initially started as a Platform as a Service company. It was initially released in the form of open source. Docker was initially primarily developed for UNIX to isolate the Linux kernel features.
Now, if you are looking for a job that is related to Docker, then you need to prepare for the 2023 Docker Interview Questions. It is true that every interview is different as per the different job profiles. Here, we have prepared the important Docker Interview Questions and Answers, which will help you get success in your interview.
Below are the 10 important 2023 Docker interview questions and answers that are frequently asked in an interview. These questions are divided into two parts are as follows:
Part 1 – Docker Interview Questions (Basic)
This first part covers basic Interview Questions and Answers.
Q1. What is Docker?
Answer:
A Docker is defined as the platform for containerizing the applications to isolate them from each other in order to ensure high availability and more efficiency irrespective of the environments such as Development, Testing or Production. All the application related dependencies such as libraries, jar files, server related configurations, infrastructure-related elements will be packaged and formed as container called containerized application which does not need any dependency and works independently. It ensures the application to be run irrespective of external factors. Containers in Docker have support from Docker Engine and Host Operating System to support all the operational or infrastructural-related dependencies.
Q2. What are the components of Docker Architecture and explain?
Answer:
This is the common Docker Interview Questions asked in an interview. The Docker works on client-server architecture. The Docker client establishes communication with the Docker Daemon. The Docker client and daemon can run on the same system. A Docket client can also be connected to a remote Docker daemon. The different types of Docker components in a Docker architecture are–
- Docker Client: This performs Docker build pull and run operations to establish communication with the Docker Host. The Docker command uses Docker API to call the queries to be run.
- Docker Host: This component contains Docker Daemon, Containers and its images. The images will be the kind of metadata for the applications which are containerized in the containers. The Docker Daemon establishes a connection with Registry.
- Registry: This component will be storing the Docker images. The public registries are Docker Hub and Docker Cloud, which can be s used by anyone.
Q3. What is Docker Container?
Answer:
A Docker Container is a form of encapsulation to the application which holds all the dependencies which share the kernel with other containers in the duration of running the isolated processes on the host operating system. A Docker container can be created by creating a Docker image. These Docker images can be run after that using Docker commands. Docker containers are the instances of the Docker images at the runtime. Docker images can be stored in any public host or private host like the Docker hub. Docker Image is a set of files that can be run in an isolated process.
Q4. What are Docker Image and Docker Hub?
Answer:
The Docker Image is a set of files and a combination of parameters that will allow creating the instances to run in separate containers as an isolated process. The Docker hub is a kind of repository to the images where these images can be stored, and this access is public. The Docker run command can be used to create the instance called a container, which can be run using the Docker image. Docker hub is the largest public repository of the image containers, which is being maintained by the community of developers and individual contributors.
Q5. What are the different functionalities and applications of using Docker?
Answer:
The different functionalities and applications of using and implementing Docker are as below:
- It simplifies the configuration and provides ease at infrastructure level configuration.
- It manages the code pipeline easily, which provides a consistent environment and stability in the application.
- It enables the isolation of the application.
- It improves the productivity of the developer by allowing the developer to solely concentrate on business logic.
- It enables a lot of debugging capabilities that provide extremely useful functionalities to implement.
- It enables rapid deployment in the form of virtualization at the operating system level.
- It reduces the utilization of multiple servers in the form of containerization.
Part 2 – Docker Interview Questions (Advanced)
Let us now have a look at the advanced Interview Questions.
Q6. What is a Docker Registry?
Answer:
A Docker Registry is a place where all the Docker Images will be stored, and Docker Cloud and Docker Hub are the public registries where these images can be hosted upon. The Docker hub is the default storage for the Docker Images. An own registry can also be set up as per the requirement. Docker Data Center (DDC) can also be used, which includes DTR (Docker Trusted Registry). Docker store will provide the feature of buying and selling the Docker images.
Q7. What is the lifecycle of Docker Container?
Answer:
This is the most popular Docker Interview Questions asked in an interview. The life cycle of the Docker container is as below:
- Create a container.
- Run the Docker container.
- Pause the Container.
- Unpause the Container.
- Start the Container.
- Stop the Container.
- Restart the Container.
- Kill the Container.
- Destroy the Container.
Q8. What are Docker Objects?
Answer:
The Docker Objects are Docker Images, Services, and Docker Containers. A Docker Image is a read-only template with the configuration or runtime instructions for the Docker container. The Services allow scaling the containers across the different Docker Daemons. These all together work as Swarm.
Q9. What are Docker Namespaces?
Answer:
The Namespaces in Docker is a technology that provides isolated workspaces called the Container. Namespaces provide a layer of isolation for the Docker containers.
Q10. What are the important Docker commands?
Answer:
| Command | Description |
| dockerd | To launch Docker daemon. |
| build | To build an image file for docker. |
| create | To create a new container. |
| kill | To kill a container. |
| commit | To create a new image from container changes. |
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