Q. What is the difference between a Docker container and a virtual machine?
A Docker container is a lightweight, portable environment that contains all of the dependencies and libraries required to run an application. Containers run directly on the host operating system and share the host's kernel, making them faster and more efficient than virtual machines. In contrast**, a virtual machine emulates an entire operating system and runs within a hypervisor, which requires more resources and is less efficient than a container.**
Q. What is Docker?
Docker is a popular open-source platform used to build, deploy and run applications in containers.
Docker is a tool that lets developers package up their software applications and dependencies into portable containers, which can be run on any platform that supports Docker.
Q. How does Docker work?
Docker works by using containers to package and isolate applications along with their dependencies and libraries. Docker containers are built from Docker images, which contain all of the necessary files and configuration settings to run an application. Once an image is built, it can be run within a container using the Docker runtime, which manages the container's resources and provides access to the host operating system.
Q. What is Dockerfile?
A Dockerfile is a text file, which contains instructions for building the image. These instructions specify the base image to use, the commands to run, and any configuration settings or dependencies required by the application.
Q. What is Docker Image?
In Docker, an image is a read-only file that contains everything needed to run an application, including the code, libraries, dependencies, and runtime environment. It's a snapshot of a container that can be used to create new containers that are identical to the original.
Q. What is Container?
Docker containers are similar to virtual machines, but they are more lightweight and have a smaller overhead. Each container runs as an isolated process on the host operating system, sharing the kernel with other containers and the host itself. This allows containers to be more resource-efficient and portable than virtual machines.
Q. How do you create a Docker image?
To create a Docker image, you first need to write a Dockerfile, which contains a series of instructions for building the image. Once the Dockerfile is complete, you can use the "docker build" command to build the image. The Dockerfile specifies the base image to use, any packages or libraries to install, and any configuration settings required for the application.
Q. What is Docker Compose?
Docker Compose is a tool for defining and running multi-container Docker applications in single node. It allows you to define the services and dependencies for an application in a single file, and then start and stop all of the containers required to run the application using a single command.
Q. What is Docker Swarm?
Docker Swarm is a native clustering and orchestration tool for Docker containers. It allows you to create and manage a cluster of Docker nodes, and then deploy and manage services across the cluster. Docker Swarm provides features like load balancing, service discovery, and scaling, making it easier to manage large-scale container deployments.
Q. What is Docker Hub?
Docker Hub is a central repository for Docker images. It allows developers to store and share Docker images with other users, making it easier to distribute and deploy applications. Docker Hub also provides tools for automating image builds, managing permissions, and scanning images for security vulnerabilities.
Q. What is the difference between docker image and docker container?
The main difference between a Docker image and a Docker container is that an image is a static, read-only file that contains the application code, libraries, dependencies, and configuration required to run the application, while a container is a running instance of that image.
In other words, an image is a template or a blueprint for a container, while a container is a live instance of that image, with its own state and settings.
Q. What is docker stack and docker swarm? Explain the difference btw this two?
Docker Swarm is a container orchestration tool that enables the management of a cluster of Docker hosts, providing high availability and scalability to your application. With Swarm, you can deploy, manage, and scale services and containers across multiple Docker hosts.
Docker Stack, on the other hand, is a tool that allows you to deploy a stack, which is a group of interrelated services, across a Docker Swarm cluster. A stack can be thought of as a group of related services that make up an application, such as a web server, a database, and a caching layer. Docker Stack uses a YAML file to define the services that make up the stack, and it can deploy and manage these services across a Docker Swarm cluster.
The main difference between Docker Swarm and Docker Stack is that Docker Swarm is the container orchestration tool, while Docker Stack is a tool for deploying stacks of services on a Docker Swarm cluster. In other words, Docker Swarm is used to manage the infrastructure and Docker Stack is used to manage the applications running on that infrastructure.