Top Docker Interview Questions For 2018
Docker Interview Questions
Docker containers can be considered as the new era of virtualization. Docker containers are replacing Virtual Machines, this is a well-known fact now. So be prepared to answer a few questions on Docker in your next interview. If you aspire to outshine yourself in your upcoming DevOps interview, going through these top Docker interview questions is a must. These questions are very carefully handpicked after discussing with many interviewers and experts.
Q1. What are the differences between Docker and Hypervisors?
| Features | Hypervisors | Docker |
| Default Security Support | To a great degree | To a slightly less degree |
| Memory on disk required | Complete OS plus apps | App requirement only |
| Time Taken to start up | Substantially longer as it requires boot of OS plus app loading | Substantially shorter as apps only need to start as the kernel is already running |
| Portability | Portable with proper preparation | Portable within image format; typically smaller |
| Operating System | Supports multiple OS | It uses the host OS |
Q2. What is Docker?
I will suggest you start with a small definition of Docker.
- Docker is a containerization platform which packages your application and all its dependencies together in the form of containers so as to ensure that your application works seamlessly in any environment be it development or test or production.
- Docker containers, wrap a piece of software in a complete filesystem that contains everything needed to run: code, runtime, system tools, system libraries etc. anything that can be installed on a server.
- This guarantees that the software will always run the same, regardless of its environment.
You can refer the diagram shown below, as you can see that containers run on a single machine share the same operating system kernel, they start instantly as only apps need to start as the kernel is already running and uses less RAM.
Q3. What is Docker image?
I will suggest you go with the below-mentioned flow:
Docker image is the source of Docker container. In other words, Docker images are used to create containers. Images are created with the build command, and they’ll produce a container when started with the run. Images are stored in a Docker registry such as registry.hub.docker.com because they can become quite large, images are designed to be composed of layers of other images, allowing a minimal amount of data to be sent when transferring images over the network.
Tip: Be aware of Docker hub in order to answer questions on pre-available images.
Tip: Be aware of Docker hub in order to answer questions on pre-available images.
Q4. What is Docker container?
This is a very important question so just make sure you don’t deviate from the topic and I will advise you to follow the below mentioned format:
Docker containers include the application and all of its dependencies, but share the kernel with other containers, running as isolated processes in user space on the host operating system. Docker containers are not tied to any specific infrastructure: they run on any computer, on any infrastructure, and in any cloud.
Now explain how to create a Docker container, Docker containers can be created by either creating a Docker image and then running it or you can use Docker images that are present on the Dockerhub.
Now explain how to create a Docker container, Docker containers can be created by either creating a Docker image and then running it or you can use Docker images that are present on the Dockerhub.
Docker containers are basically runtime instances of Docker images.
Q5 What is Docker hub?
Answer to this question is pretty direct.
Docker hub is a cloud-based registry service which allows you to link to code repositories, build your images and test them, stores manually pushed images, and links to Docker cloud so you can deploy images to your hosts. It provides a centralized resource for container image discovery, distribution and change management, user and team collaboration, and workflow automation throughout the development pipeline.
Q6. How is Docker different from other container technologies?
According to me, below, points should be there in your answer:
Docker containers are easy to deploy in a cloud. It can get more applications running on the same hardware than other technologies, it makes it easy for developers to quickly create, ready-to-run containerized applications and it makes managing and deploying applications much easier. You can even share containers with your applications.
If you have some more points to add you can do that but make sure the above the above explanation is there in your answer.
If you have some more points to add you can do that but make sure the above the above explanation is there in your answer.
Q7. What is Docker Swarm?
You should start this answer by explaining Docker Swarn.
Docker Swarm is native clustering for Docker. It turns a pool of Docker hosts into a single, virtual Docker host. Docker Swarm serves the standard Docker API, any tool that already communicates with a Docker daemon can use Swarm to transparently scale to multiple hosts.
I will also suggest you to include some supported tools:
- Dokku
- Docker Compose
- Docker Machine
- Jenkins
Q8. What is Dockerfile used for?
This answer, according to me should begin by explaining the use of Dockerfile.
Docker can build images automatically by reading the instructions from a Dockerfile.
Now I will suggest you to give a small definition of Dockerfle.
A Dockerfile is a text document that contains all the commands a user could call on the command line to assemble an image. Using docker build users can create an automated build that executes several command-line instructions in succession.
source https://www.edureka.co/blog/interview-questions/docker-interview-questions/
source https://www.edureka.co/blog/interview-questions/docker-interview-questions/
0 comments:
Post a Comment