What is Container, What is Docker on Container - Get Started

This tutorial will help you to understand everything about containerization also called Container. At the end of this article, you will be able to understand the below topics,

1. Why do we need containerization?
2. What is container?
3. Difference of conterization over virtualization
4. Advantages of container
5. What is docker on container?

In the previous posts, already we have explained the below topics. Refer those links to understand this topic from basics.

What is Docker - Get Started from Basics - Docker Tutorial
What is Container, What is Docker on Container - Get Started
How to Install Docker on CentOS 7 / RHEL 7
Docker Images Explained with Examples - Docker Tutorial
Dockerfile Instructions Explained with Examples
Docker ONBUILD Command Explained with Examples
Docker ARG vs ENV Command Differences Explained in Detail
Docker CMD & ENTRYPOINT Differences Explained in Detail

What is Container, What is Docker on Container - Get Started

Lets get started.

Also Watch this "What is Container" Tutorial video on our YouTube Channel.

Why do we need containerization (Container)?

Containers are a solution to the problem of how to run the applications efficiently when moved from one environment to another environment. This is what the biggest problem we had before containerization.

lets say,  A developer has developed the Application code in his own machine, and it was working fine in his machine. But when he moved the same code to development server, application will not work properly.

Because, His own machine and development environment server configuration and versions are not similar. He developed the application code in python 2 and Development server has python 3.

So again he need to work on the application code to make it work based on development server version ie Python 3. Now he fixed the issue and its working now on development server.

This time, He is moving the application code to testing or production environment. But still not working because of some libraries are missing to run the application.

Its a big problem. So we needed a solution to make the applications able to run anywhere, on any machine.

That is why we have a technology called containerization (Container).

What is Containerization (Container)?

Containerization is a lightweight virtualization technology alternative to hypervisor virtualization. Any application can be bundled in a container can run without any worries about dependencies, libraries and binaries.

Because container creates the isolated environment with all the required dependencies, libraries and binaries to run your application with out any issue. Hence you can build the packages, ship the application to any environment and run it.

So Containers are designed to run on physical servers, virtual machines and any cloud instances.

Difference of containerization and Virtualization

Virtualization technology that allow us to have multiple operating systems to share a single hardware processor.

It is mainly used to utilize the maximum hardware resources efficiently by deploying the application into “virtual machines” (VMs) with their own operating systems, so an application can run independently on top of a server’s operating system which is a dedicated virtual machine for an application.

Operation system / Guest OS lies on top of the hypervisor softwares. That might be Vmware esx, Microsoft Hyper V, Kvm, Xen and so on.

But Container runs on a single operating system i.e. host os, and each container shares the Host operating system kernel with the other containers.

Here you would have only one operating system, on top of it you will have applications within container, so it doesnt require an additional operating system for each application as we have in virtualization technology.

So i would say Containerization is an application-specific virtualization, because it provides application with dedicated environments in the form of container to run on, which can be deployed and run anywhere without a dedicated virtual machine with Operating system for each application.

Also Container was designed to solve modern problems and application management issues. so it’s not a replacement for virtualization,  but it’s complementary to it.

Advantages of Container

Containers are isolated, doesnt require operating system and it shares a host kernel. So containers run on the same server and use the same resources, they do not interact with each other because its isolated.

If one application crashes, other containers with the same application will keep running without any issues.

Its a Portable and light weight operating system and it contains only the required binaries, dependencies and libraries to run the application. so it can be move anywhere easily and can run without worrying about compatibility, dependencies kind of issues.

Faster and Resource Efficiency - Its very fast to boot, because containers are lightweight and start in less than a second since they do not require an operating system boot.

Resource efficiency Since containers do not require a separate operating system, they use less resources.

Improves Scalability and lowers costs - By allowing more containers in the environment without the need for more servers, containerization increases scalability anywhere from 10 to 100 times that of traditional VM environments.

What is Docker on container?

Docker is a tool designed to manage the containers. Using Docker you can create, deploy, and run the applications containers.

Hope you have got an idea about container, Going forward, we will play more with docker and containers.

If you are interested in learning, Request you to go through the below recommended tutorial.

DevOps Full Course Tutorial for Beginners - DevOps Free Training Online
Docker Full Course Tutorial for Beginners - Docker Free Training Online
Kubernetes Full Course Tutorial for Beginners - Kubernetes Free Training Online
Ansible Full Course Tutorial for Beginners - Ansible Free Training Online
Openstack Full Course Tutorial for Beginners - Openstack Free Training Online

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