Docker Interview Questions and Answers
Question - 101 : - Explain containerization?
Answer - 101 : - Docker containers contain different software packages like code, system tools, libraries, runtime, and settings required to run an application. The apps reside on top of the Docker engine layer. This is called containerization. It helps applications to run smoothly regardless of the environment.
Question - 102 : - Explain Docker Images, Docker Hub, Docker File?
Answer - 102 : -
Docker images: These are files that contain multiple layers and are used to execute code inside the Docker container. Images are built from instructions for an executable version of an application. Images speed up docker build by allowing each step to be cached.;
Docker hub: It is a service that finds and shares container images within a team. You can push and pull images, access private repositories of container images, build container images automatically from Github (or Bitbucket), and push them to DockerHub. Docker itself provides the service. Read more.
Docker file: It is a text document used to build an image. It contains instructions and commands to build the image. Docker reads the commands and assembles the image automatically.
Question - 103 : - How to Check for Docker Client and Docker Server version?
Answer - 103 : -
We can check the docker version using the command docker version [options]. If we do not give any options, then Docker gives all the version related information about client and server. For example, to get only the server version, use:
$ docker version --format '{{.Server.Version}}'
Question - 104 : - Explain the login procedure to Docker Repository?
Answer - 104 : -
To log in to the Docker repository, use the following command:
docker login [OPTIONS] [SERVER]
For example, to login to a self-hosted (local) registry, you can add the server name:
$ docker login localhost:8080
Question - 105 : - Explain various Docker Basic Commands?
Answer - 105 : -
Some Docker commands are:
- docker push: pushes repository or image to a registry
- docker run: runs a command in a new container
- docker pull: pulls repository or image from a registry
- docker start: starts one or more containers
- docker stop: stops running containers
- docker search: searches for an image in a docker hub
- docker commit: commits new image
Answer - 106 : - Docker containers can be easily deployed to any cloud platform. Also, developers can create ready-to-run containerized applications faster and manage and deploy applications easily. Containers can also be shared with applications. These features are not present in other containerization methods.
Question - 107 : - List out the platform where Docker runs on.
Answer - 107 : -
It runs on Windows (x86-64) and Linux (on x86-64, ARM, and other CPU architectures), s390x, ppc64le.
Question - 108 : - Is it possible for a container to restart by itself?
Answer - 108 : -
Yes, it is possible. Docker defines certain policies to restart the container. These are Off: container won't be restarted if it stops or fails,
- On-failure: container restarts only when a failure that occurred is not due to the user,
- Unless-stopped: container restarts only when a user executes the command to stop it,
- Always: the container is always restarted irrespective of error or other issues.
- The command is:
$ docker run -dit — restart [unless-stopped|off|on-failure|always] [CONTAINER]