Docker Interview Questions and Answers
Docker hit the IT industry and enterprises in the year 2013. By the end of last year, it almost hit 10 billion container images and so is the demand for Docker and its professionals are increasing enormously. This has also resulted in an exponential rise in job openings for the same. If you want to be on top of the pre-race preparation in Docker software it is advisable to go through the advanced set of Docker interview questions. These will not only assure success whether you will achieve a supreme position amongst other competitors. So go ahead and take advantage of the below-mentioned question and answers set.
Most significant features of Docker from other competitive technologies are-
- The Docker container can be run on PC as well as the company's or Enterprise's IT system.
- As Docker is a repository of containers it can be deployed and downloaded on all the applications from a centralized location
- The applications can be shared actively with all the containers that were created earlier.
Most Frequently Asked Docker Interview Questions
On broad terms, Docker and hypervisor form the same working but still, there is a wide range of differences between them. Docker is a lightweight technology as it raises fewer resources and also hosts kernel. Hypervisor technology creates the Colonel rather than hosting.
Most significant features of Docker from other competitive technologies are-
- The Docker container can be run on PC as well as the company's or Enterprise's IT system.
- As Docker is a repository of containers it can be deployed and downloaded on all the applications from a centralized location
- The applications can be shared actively with all the containers that were created earlier.
Docker Swarm is a way of orchestrating the Docker containers where Dockers can be implemented in a cluster. To support the easy monitoring and Management Docker pools can be converted into an individual Docker Swarm.
Note: This is one of the essential Docker interview questions and answers.
A complete set of instructions that are used to pass on the Docker to help in the image build-up is known as Dockerfile. It can be also considered as a text document having all the necessary commands which are required for creating a Docker image. An automated build can also be created which executes various command lines one after the other.
The difference between Docker and the virtual machine is as follows-
| Virtual machines | Docker containers |
|---|---|
| It essentially requires more resources. | It requires fewer resources. |
| Process isolation is performed at the hardware level. | The process isolation is performed at the operating system level. |
| It has a separate operating system for every virtual machine. | The resources of the operating system are shared within the Docker container. |
| Virtual machines can be easily customized. | The setup of a custom container is easy. |
| Creating a virtual machine requires time | Creating the Docker is faster in comparison to virtual machines. |
| Booting is not quick. | Booting is also performed quickly. |
The Docker container can be created from any specific Docker image of the user's preference and the same can be obtained using the command-
Docker run t - i command name
This command will help you create the container and the same will start for you. To check the stability of the Docker container and if it is created or not, you can use the command mentioned below. This command will also check if it is running or not and it will list out all the containers along with their status on the host system where the Docker container is running. Docker ps-a
At present doctor is actively available on the platforms mentioned below-
- Ubuntu 12.04, 13.04
- Fedora 19/20+
- CentOS 6+
- RHEL 6.5
- Gentoo
- ArchLinux
- OpenSUSE 12.3+
- CRUX 3.0
At present Docker is also available on the cloud environment and the platform it supports are-
- Amazon EC 2
- Google compute engine
- Microsoft azure
- Rackspace
The user required Docker-compose up UP is used to start or restart the services which are defined under Docker-compose.yml. In the default attached mode, all the logs from containers will be visible to you. In detached mode composed exits by starting the container but containers pursue running in the background.
The Docker-compose run command is utilized for ad hoc or one-off tasks. They also require the services name in which the user wants to utilize run and only start the container for the same services which are dependent on the running services. It is also used to test or perform administrative tasks like removing or adding data to the volume container.
The Docker-compose start command is used to restart the containers that were created earlier but stopped. With this command, new containers cannot be created.
Docker uses cache to enhance the speed of building the project and other instances. All the commands mentioned in the Docker file are used to build other Docker containers and its outcomes are separately stored in a layer. These layers are built on top of every other layer.
Docker runs the Docker file and makes an effort to execute steps one after the other before the finalization. Developing the Docker images with a Docker file is extremely faster as compared to the provision with ansible. This is possible because of the utilization of Docker cache and supreme based images.
Docker containers are rapidly gaining popularity at the enterprise level and it is certainly becoming an essential part of several professional pipelines. Docker is one of the supreme and effective platforms for organizations that understand the consequences of containerization.
In Docker, there can be as many containers defined per host because Docker does not restrict anyone of them. The only thing to be considered is that every container requires the storage space, memory and CPU supporting the hardware as well. It is also advised to consider the size of application as containers are lightweight and extremely dependent upon the host operating system
It is no longer difficult to fulfill your passion being in Docker software with the help of best Docker interview questions and answers. As they will completely assist you by providing the knowledge and specifications of the field. The set of questions and answers are also provided in an organized way considering the levels and increasing the chances of your selection.