The Role of Docker in DevOps
Tags: docker, beginners, career
Published: 2020-02-22 07:43:22

A developer builds an application and sends it to the tester. But, the environments of development and testing systems are different; thus, the code does not work. There are two solutions to this: Docker and Virtual Machines, but Docker is far better in terms of performance, scaling, and efficiency. 
In this article, we will dive into Docker, its comparison with VMs, and its uses with DevOps. 

###What is Docker?
Docker is an open-source project with a friendly-whale logo that facilitates the deployment of applications in software containers. It is a set of PaaS products that deliver containers (software packages) using OS-level virtualization. It embodies resource isolation features of the Linux kernel but offers a friendly API. 

In simple words, Docker is a tool or platform design to simplify the process of creating, deploying, and packaging and shipping out applications along with its parts such as libraries and other dependencies. Its primary purpose is to automate the application deployment process and operating-system-level virtualization on Linux. It allows multiple containers to run on the same hardware and provides high productivity, along with maintaining isolated applications and facilitating seamless configuration. 

####Docker benefits include:
* High ROI and cost savings
* Productivity and standardization
* Maintenance and compatibility
* Rapid deployment
* Faster configurations
* Seamless portability
* Continuous testing and deployment
* Isolation, segregation, and security

####Docker vs. Virtual Machines
Virtual Machine is an application environment that imitates dedicated hardware by providing an emulation of the computer system. Docker and Vmboth have their set of benefits and uses, but when it comes to running applications in multiple environments, both can be utilized. So which one wins? Let's get into a quick Docker vs. VM comparison. 

OS Support: VM requires a lot of memory when installed in an OS, whereas Docker containers occupy less space. 

Performance: Running several VMs can affect the performance, whereas, Docker containers are stored in a single Docker engine; thus, they provide better performance. 

Boot-up time: VMs have a longer booting time compared to Docker. 
Efficiency: VMs have lower efficiency than Docker.

Scaling: VMs are difficult to scale up, whereas Docker is easy to scale up. 

Space allocation: You cannot share data volumes with VMs, but you can share and reuse them among various Docker containers. 

Portability: With VMs, you can face compatibility issues while porting across different platforms; Docker is easily portable. 
Clearly, Docker is a hands-down winner. 

###What is DevOps?
Before talking about how Docker integrates with and simplifies DevOps, let's briefly discuss DevOps and its uses. In a nutshell, DevOps is an ecosystem or set of practices that automate processes between development, testing, and IT teams to facilitate seamless building, testing, launching of the software efficiently and reliably. 

####DevOps benefits include:

Technical advantages:
* Fast and continuous software delivery
* Quicker resolution of problems
* Reduced management complexities

Business advantages:
* Fast feature delivery
* Enhanced collaboration and communication
* More time for creativity and innovation
* Stable operating environments

Cultural benefits:
* Happier, productive. and collaborative teams
* Improved employee engagement
* More growth opportunities

###Docker for DevOps
Docker is a platform that turns out to be a perfect fit for the DevOps ecosystem. It is developed for software companies that are struggling to pace up with the changing technology, business, and customer requirements. The benefits Docker offers to the DevOps environment has made it an irreplaceable tool in the toolchain. 

The reason for Docker being soo good for DevOps is its benefits and use cases of containerizing the applications that support the development and quick release. DevOps is primarily used to overcome 'Dev' and 'Ops' problems, and Docker seems to solve most of them, with the main one being that it can work on any machine. Thus, it allows all the teams to collaborate and work effectively and efficiently. 

Docker allows you to make inevitable development, production, and staging environments, thereby providing you seamless control overall changes. If you want to return to the previous version, you can do that anytime, as all the environments become more alike. Docker guarantees that if a feature is functioning in the development environment, it will work in the production and staging environment as well.  

####Best practices for creating Docker images
* Begin with an appropriate base image
* Use multi-stage builds. If you want to use a Docker version that does not include multi-stage builds, try reducing the number of layers in your image.
* If you have multiple images that have a lot in common, you can create your own base image with shared components and then base your unique images on them. 
* Use production image as the base image to keep production image lean but enable it for debugging
* When you build images, consider tagging them with useful tags that codify intended destination, version information, and stability.

###How Docker improves the DevOps approach?
One of the biggest benefits of using Docker with DevOps is that developers, testers, and system admins all use it. For instance, developers can use Dockerfiles to create Docker images on local computers and run them. The system administrators can use the same Docker images to make updates and stage the production environments. 

Thus, you can create stable environments for development, production, and staging; this approach offers several benefits as well, as discussed below. 

###Benefits of using Docker with DevOps
Docker and DevOps, both intend to promote collaboration among various teams involved in a software life cycle. Although the two platforms offer a broad range of development, business, and cultural benefits, they have some drawbacks as well. The good news is, these pitfalls can be overcome by using the two concepts together. 

####Here are some key benefits of using Docker with DevOps

* You get a high level of control over all the changes because they are made using Docker containers and images. Thus, you can return back to the previous version whenever you want to. 

* With Docker, you get a guarantee that if a feature is working in one environment, it will work in others as well. 

* Docker, when used with DevOps, simplifies the process of creating application topology embodying various interconnected components. 

* It makes the process of load balancing configuration easier with Ingress and built-in service concepts.

* It enables you to run CI/CD using them, which is more comfortable to use when compared to just using it with Docker. 

####Final thoughts
Docker is a revolutionary technology that is adopted and loved by many. It provides a unified platform for all the stages of application development, ensuring seamless collaboration among development and testing teams. DevOps environment consists of various continuous stages, including development, integration, testing, deployment, and monitoring. 
Docker is used in the Continuous Deployment stage of the DevOps ecosystem and plays a vital role in the environment. With the security, scalability, and simplicity it brings to the software cycle, Docker is a must-use in any DevOps environment.

To know more about Docker, you can sign up to [KodeKloud](https://kodekloud.com/) and [learn Docker for free](https://kodekloud.com/p/docker-for-the-absolute-beginner-hands-on).

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