Posted on : 17 May, 2021, 10:14:29 AM
Docker is setting off a clear path on core development capabilities, establishing a conversation between containers and cross-service management, which is also known as libcontainer, libchan, and libswarm. Meanwhile, industries are already showing a willingness for their own ecosystem to consume with the Orchard Labs acquisition.
Docker was released in 2013 and is known as a helpful tool for application packaging, shipping, and running in containers. Many big companies such as IBM, Google, VMware, Amazon, and Red Hat, etc., have looked towards Docker as the go-to technology for containers that clears that it is high time to learn and make a career out of it. So go ahead and take advantage of all the latest job openings for docker professionals with this blog that Wissenhive designed with the industry expert includes the top 50 frequently asked Docker interview questions.
Docker refers to a lightweight open-source technology used for containerization. It has gained widespread popularity in the application packing world and cloud computing services. Docker allows an individual to automate the application deployment in portable and lightweight containers.
There are six different features included in Docker.
There are few drawbacks of Docker, which includes
A Docker container refers to a standard unit of the software that holds, operates, and packages up code with its dependencies to make the application run quickly, smoothly, and reliably from one computing ecosystem to another. An image contained in a docker container is an executable, standalone, and lightweight software package that combines everything needed to run an application, such as system tools, System setting, system libraries, runtime, and code.
There are mainly four uses of Docker container, and those are
Container orchestration helps in maintaining and managing the containers running in a large and dynamic environment. It can automate and control the tasks such as
The Docker images help in building docker containers, and individuals can create the Docker images with the build command. Due to this procedure, it creates a container that starts when it begins to run. Docker registry helps in storing all the built images in Docker.
All the Docker images are stored in Docker Registry. The Docker Hub refers to a public registry that is the default storage for docker images. Docker Cloud is another public registry, and the docker hub is one of the most significant public storehouses for image containers, which is maintained and managed by a large number of developers consistently along with individual contributors.
Hypervisor refers to software that helps in presenting thoughts through visualization, which is also known as Virtual Machine Monitor. It divides the host system into several systems and allocates the resources to every distributed virtual environment. An individual can have the various OS on a particular separate host system through this.
Virtualization is the process used to build a software-based practical version of something such as servers, compute storage, application, etc. These environments or virtual versions are designed from a particular physical hardware device or system. Virtualization allows users to split one system into various sections representing distinct, separate individual systems. A software named Hypervisor performs this sort of splitting. The virtual environment produced by the Hypervisor is termed a Virtual Machine.
There are mainly three different types of Virtualization.
Docker images work on generating docker containers. There must be a registry where docker images remain live on the device. This registry is known as Docker Hub. An individual can choose any Docker Hub images and utilize them to perform customized containers and images. Currently, the Docker Hub is one of the world’s largest public repositories of image containers
Docker Architecture is made up of or consists of a Docker Engine that refers to a client-server application with some major components:
The three main components of Docker architecture are
A Dockerfile is a text report or document which holds all the commands, and an operator could name or call to assemble an image on the command line. Users can design an automatic build that performs numerous command-line instructions in succession by using Docker build.
The common instructions used in Dockerfile are
Docker Compose is a YAML file containing details about the networks, services, and volumes for setting and fixing up the Docker application. Users can use Docker Compose to build particular containers separately, hosting them and preparing them to interact with each other. Each and every container will present a port for interacting and communicating with other containers.
Docker Swarm refers to a native clustering for Docker, which helps in turning a pool of docker hosts into a virtual, single Docker host. It serves the standard Docker API, and any tools that are already interacting and communicating with Daemon of Docker can use Docker Swarm to scale to multiple hosts transparently.
A Namespace is a feature of Linux and plays an important role in containers. It helps in adding the isolation layer in containers. Docker gives multiple namespaces in order to stay portable, manageable, and not harm the underlying host of the system. Some types of Namespace supported by Docker include Mount, User, PID, IPC, and Network.
Docker machine is a mechanism that allows users on virtual hosts to install Docker Engine. These virtual hosts can now be managed using the commands of docker-machine. Docker machines also give individuals provision Clusters of Docker Swarm.
Memory-swap refers to a modified flag process that only has worth if the memory is also set. Swap provides the container to communicate and express memory specification and requirements to disk when the container has consumed all the RAM that is available to it.
This command is “$ docker system prune” used for removing all the paused or stopped containers, each and every network that is not in use, all build caches and all dangling images. It is known as one of the most useful commands in docker.
There are five different types of Docker commands, and those are
Docker swarm is a native tool that is used for scheduling and clustering Docker containers. IT supervisors, developers, use docker swarm to build, manage and maintain a set of nodes in the solitary virtual system or Docker.
Docker objects include three different terms, and those are Docker images, docker services, and Docker containers.
There are three different types of the default network in Docker, and those are
Docker object labels is a process that helps in applying metadata to docker objects including,
The communication happens between Docker Daemon and Docker Client with the combination of
When there are changes in the deployment process within a production environment, then the basic deployment process is followed.
|Process||One container can’t see processes in another container.||Process in on Virtual Machine can’t see processes in another VM.|
|Root File||Every container has its own root file system||Every Virtual Machine has its own root filesystem.|
|Virtual Network Adapter||Can get a virtual network adapter with the separate ports and IP||Can get its own virtual network adapter|
|Running Instances||Docker containers are running instances of Docker Image||A virtual machine is a running instance of physical files (.VMDK and . VMS)|
|Host OS||It can be different from Container OS||Can be the difference from guest OS|
|Operating System||All containers share the same host kernel||Every Virtual Machine runs its own OS|
|Boot up timing||In seconds||In seconds|
|Snapshots||Images are incrementally built on top of another layer with lots of snapshots/images.||Virtual machines use snapshots or images sparingly.|
|Version Controlled||Images can be different and version-controlled Docker Hub such as GITHUB.||Neither effective differences nor version controlled.|
|Running in Laptop||Able to run many Docker containers on a laptop||Not able to run more than a couple of Virtual machines on a laptop.|
There are mainly two different ways to configure the Docker Daemon, and those are by using a
IT contains Docker images, containers, and daemons, which offers a complete environment for executing and running the applications.
The full form of CNM is Container Networking Model, which is the specification and standard from Docker, Inc. that forms a container networking basis in the Docker environment. It is one of the approaches of Docker to provide networking to the container with support from various network drivers.
Bridge networks help in connecting two different networks while building a particular aggregate network from various network segments or communication networks.
Overlay networks are used for building a virtual network between two separate hosts. Virtual since networks are created over an existing network.
Bridge networks can provide or work with a single host, while overlay networks are designed for multiple hosts.
|Scope||Hyper-V Container||Windows Server Container|
|Basic Image||Can be different from the host||Same as host|
|Kernel||Independent kernel||Shared with host|
|Admin within Container||Yes||No|
|Resource Management||New services started inside||Same sharing with the host|
|IP||New IP address per instance||New IP address per instance or shared host's|
|Domain join support||Yes||No|
|Machine Identify||Different||Same as host|
|Support for Block Storage||No||Yes|
In a Dockerfile, both ENTRYPOINT and CMD instructions define that command will be administered while running containers. There are some rules for their cooperation, such as
Docker implements functionalities such as docker events and docker stats for monitoring Docker in production. Docker stats include memory and CPU usage of the container. Docker events work on providing detailed information about the activities that are taking place in the docker daemon.
There are three different types of mounts available in docker.
Here, this blog brings us to the end of the top 50 interview questions on docker asked by interviewers in a Docker professional interview. Wissenhive covered almost every question that can help you in gaining and updating your knowledge to the next level and help you in clearing your interview.
Are you stuck with any questions? Feel free ''Learners'' to mention it down in the comment section, and we will get back to you as soon as possible.
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