What is Docker and How to install Docker?
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What is Docker?
Docker is a containerization technology that enables us to cleanly abstract an environment configuration to a file (or set of files), and run it in a protected, isolated environment on a host. This is similar to but more performant than, a virtual machine. On a lower level, this secure isolation is achieved via application namespaces, similar to how Linux LXC and BSD jails work. This provides isolation for services without the overhead of running an entire operating system on the host.
What is Dockerfile?
A Dockerfile is a file that contains a set of instructions that describe an environment configuration. Dockerfiles starts with defining a docker image FROM which the build process starts. Followed by various other methods, commands, and arguments (or conditions), in return, provide a new image that is to be used for creating docker containers. They can be used by providing a Dockerfile content - in various ways - to the Docker daemon to create an image.
What is Dockerfile Syntax?
Dockerfiles use simple and easy syntax which makes them strikingly easy to create and use. They are designed to be
easily understood, especially because they allow commenting just like a good and properly written application source-code.
What is Docker Image?
A Docker image is a template that contains a set of instructions that is used to create a container that can run on the Docker platform. It provides a convenient way to package up applications and preconfigured server environments, which you can use for your own private use or share publicly with other Docker users.
What is Docker Container?
Docker is a standard unit of software that stores up all your code and its dependencies so the application runs fast and reliably from one computing environment to different ones. Containers can be started, running, restarted, and stopped. We're able to create as many containers from a single image as we need. This Concept helps to scale up a service easier .re-built Dockerfile. It is ready to run and can be run on any host the only requirement is installed, docker. The concept of images is where Docker gets its portability.
What is Docker Hub?
Docker Hub may be a cloud-based repository during which Docker users and partners create, test, store, and distribute container images. Through Docker Hub, a user can access public, open-source image repositories, also as use an area to make their own private repositories, automated build functions, webhooks, and workgroups.
How to install Docker in RHEL 8?
1.Configure the YUM Repository for Installing docker : cd /etc/yum.repos.d/
2.Create a file with extension .repo and copy the following code :
3. Save the file.
4. Now yum repository is configured, now we can install docker in our RHEL 8: yum install docker -y
5. To check whether Docker is installed properly use Command: docker --version
6. How to pull the Docker image in RHEL 8?
"docker pull image_name "