Docker for beginners

The Docker is basically an open-source, portable, extensible Linux based containerization Platform which is being used for automating deployment, scaling, and management of application. Like Kubernetes it is also being widely recommended by the developer for developing the application as it provides a better provision for building, running and packaging of application. As it is an open source and free so if we need to create a project in this technique then it is got hosted. The use of Docker enables the efficiency of process and reduces operational overheads which is a major factor for any developer during the development process. It has a extensible dev environment, which can be used to build stable and reliable applications.

Deployment strategy:

In Contrast to the deployment of work without the use of Docker was very tedious and tuff.  Especially, when the team developers are used to develop the DevOps then the managing of the application dependencies were very tuff because they need to maintain the stack across various cloud and environments. Sometimes as a routine work strategy they need to ake the application stable and operational regardless the platform they are used to run the application. Hence, to avoid such inefficiency and problems in the applications, the organizations were decided to increase the use of containerized framework which helps and allows the designing of a stable application framework without adding the contaminants such as:

• Complexities.
• Security vulnerabilities.
• Operational loose ends.

Managing the Docker resources with Cgroups

It should be get noted that the containerization is the process of packaging an application’s code with dependencies, libraries, and configuration files. These are the files which is most essential to make a standalone executable unit for a program so that the application can be able to launch and operate efficiently without having any problems. And hence, to make the containers to become practically mainstream the Docker plays a vital role. As before this the containers didn’t gain much prominence, mostly due to usability issues. 

What is Docker:

In practical way the Docker is basically a Linux based open-source containerization platform which is used to provide the developers to build, run, and package the applications in an effective manner and hassle-free environment. Unlike virtual machines, the Docker containers are mainly used to offer the following benefits to the developers like:

• Operating System-level abstraction.
• Optimum resource utilization.
• Interoperability for Efficient building of application and test.
• Faster application execution.

Docker Components

It should be get noted that the Docker containers are also used to modularize the application’s functionality. They divide the applications into multiple components which allows the developer to deploy, test or scale the application module independently as and when it is needed.

Docker Architecture: 

As we know that the Containers deployment technique are a good way to bundle and run your applications, but the biggest limitation related to downtime. It means if a container goes down due to any reason, then we need another container to get start as soon as possible. When we are going to consider the architecture prospect of Docker then certain components are very essential for this prospect that each one of us should know. The Docker is consist of following components such as:

1. Images.
2. Containers.
3. Registries, and 
4. Docker engine.

1. The Images are basically used as the blueprints which is used to contain the basic instructions. 
2. The developers are going to use this instruction for creating a Docker container. 
3. In addition to this the Images are also used to define the Application dependencies that depends between the modules and the processes which is allowed to get run when the application is going to be launches by the developer. 
4. If you need then you can get images from DockerHub.

1. The Containers are basically the live instances of images which basically used to provide a framework to run systems resiliently.
2. It also provides the better scope for scaling and failover for application, their deployment patterns.
3. In this environment the application or its independent modules are allowed to run.
4. Whenever we are going to consider the OOPS analogy, then we can say that an image is a class, and the container is an instance of that class. 
5. So, in this regards we can say that the containers are used to allow the operational efficiency by allowing the multiple containers from a single image.

1. A Docker registry is another important part in the architecture which is acts as a repository of images. 
2. It is like a hub from where the Docker is used to receive the services. 
3. Here we have the default registry for our operation which is the Docker Hub.
4. When a user will make a request for an image from Docker then by default it is get searched within the Docker Hub registry.
5. In Docker we have the public registry also which is allowed to store the public and official images for different languages and platforms. 
6. Similarly, if we need then we can also create a own a private registry and configure it. 
7. We can used to handle the various source of images for your custom requirements through the Private registry.

Docker Engine:

1. The Docker Engine is the most important core components of a Docker architecture. 
2. It is the central component which is used to manage all the Images, Registry and Container in efficient way and also allows the application to get runs in smother manner. 
3. Docker Engine is also helping the application that’s get installed on the system that manages containers, images, and builds. 
4. Whenever we are going to analyse the responsibility of Docker Engine then it uses a client-server architecture and consists of the following sub-components:
5. The Docker Daemon (A thread-based mechanism) is basically the server which allows the applications to get runs on the host machine. 
6. The prime responsibilities for this are to provide the building components for the system and managing Docker images so that the instances can be get made available.
7. Another important component is Docker Client which is a command-line interface (CLI). 
8. Through the CLI the programmer is used to send the instructions to the Docker Daemon using special Docker commands. 
9. Here the client is get allowed to run on the host machine so to connect remotely with the daemon the Docker Engine’s REST API is being get used. It is also used to enables the interactions between the client and the daemon.