🧑🏽‍💻Containers and Containerization in DevOps🔥
Tags: webdev, devops, containers, tutorial
Published: 2023-08-01 01:09:34


In this tutorial you will learn and discover the power of containers. Learn how they ensure environment consistency, enabling smooth deployment from development to production environments,Differences and between VMs and containers,and many more. Let's revolutionize your DevOps workflow with containers.
Let's go! 🎉🤓

In software development, two effective methods of bundling an application with its environment and dependencies are containers and virtual machines (VMs). Both approaches aim to minimize differences between development and production environments, enabling seamless application deployment.

1. **Containers**: Containers use containerization technology, with [Docker](https://dev.to/denzubechi/concepts-of-docker-3je9) being the most popular containerization platform. They package applications along with their dependencies, libraries, and configurations, creating isolated and portable units. Containers share the same host operating system kernel, which makes them lightweight and resource-efficient. This shared kernel facilitates faster startup times and better performance. Containers are perfect for deploying microservices-based applications and are a fundamental building block in the cloud-native ecosystem.

2. **Virtual Machines (VMs)**: Virtual machines, on the other hand, offer a different approach. They create virtualized instances of a complete operating system, including the application and all its dependencies. VMs provide stronger isolation between applications, as each VM runs its own separate kernel. While this isolation comes with some overhead in terms of resource consumption and slower startup times, VMs are highly versatile and can run a broader range of applications and operating systems.

Both containers and VMs are capable of horizontal scaling, meaning you can replicate instances to handle increased traffic or demand. This scalability is crucial for modern applications that need to adapt to varying workloads.

It's important to note that while containers and VMs offer similar benefits in terms of environment consistency and scalability, they differ significantly in their architecture and use cases. In the next page, you'll delve deeper into virtual machines, exploring their unique characteristics and how they contrast with containers.

## What is a container? 🧐
A container is a self-contained and isolated unit that encapsulates an application along with all its required dependencies and the necessary runtime environment to run the application. It leverages operating system-level virtualization to enable the execution of multiple isolated processes concurrently.
The key components of a container include:

- **Application Code**: The container holds the application's code, which includes all the files and binaries required to run the application successfully.

- **Dependencies**: Containers package all the dependencies necessary for the application to function correctly. These dependencies typically include libraries, utilities, configuration files, and any other supporting files required by the application.

- **Runtime Environment**: The container includes the runtime environment needed to execute the application. This environment ensures that the application runs consistently across different systems and environments, regardless of variations in the underlying host system.

### Benefits of Containers😋🤩
The benefits of using containers are manifold, revolutionizing the way applications are developed, deployed, and run. Here are some key advantages of containers:
- **Portability**: Containers provide an efficient and consistent way to package applications and their dependencies, making it easier for developers to move applications between different environments, such as development, testing, and production. This portability ensures that the application behaves consistently across various hardware and platforms, reducing the risk of issues caused by environment discrepancies.

- **Isolation and Efficiency**: Containers offer lightweight and isolated execution environments for applications. Each container shares the same host operating system kernel, which allows for better resource utilization and less system overhead compared to traditional virtual machines. This efficiency results in faster startup times and better performance for applications running in containers.

- **Simplified Development and Deployment**: Containers streamline the development process by bundling all the necessary components into a single package. This reduces the likelihood of "it works on my machine" issues, as developers can create applications in a controlled and consistent environment. Deployment becomes more straightforward and predictable, as the same container used in development can be deployed to production without modification.

- **Scalability**: Containers facilitate horizontal scaling, allowing applications to handle varying workloads by replicating instances of the container across multiple nodes or servers. With container orchestration platforms like Kubernetes, scaling applications becomes automated and flexible, responding to changing demand effortlessly.

- **Resource Utilization**: Containers enable higher resource density on a single host, making better use of available hardware resources. This ability to run multiple containers on a single machine contributes to cost efficiency and maximizes server utilization.

- **Version Control and Rollbacks**: Containers can be versioned, allowing developers to maintain a history of changes to the application and its dependencies. If an issue arises after deployment, it's easy to roll back to a previous version, ensuring the stability and reliability of the application.

- **DevOps Collaboration**: Containers bridge the gap between development and operations teams. Developers package applications and dependencies into containers, and operations teams can then deploy and manage these containers consistently across different environments, promoting collaboration and reducing deployment-related conflicts.

### How to create Containers? 🧑‍🔧 
Containers can be created using various container runtime/engines, each offering unique features and functionalities. Some of the well-known container runtime/engines include:
- [Docker](https://www.docker.com/products/container-runtime/): Widely recognized for its standardized packaging format, Docker simplifies container creation, distribution, and management for diverse applications.

- [CRI-O](https://cri-o.io/): Designed as a lightweight container runtime specifically for Kubernetes, CRI-O optimizes container execution within Kubernetes clusters.

- [OpenVZ](https://openvz.org/): An open-source container-based virtualization solution, OpenVZ provides isolation for Linux-based containers.

- [Containerd](https://containerd.io/): Focused on simplicity, robustness, and portability, Containerd serves as a container runtime that can work alongside higher-level container platforms.

- [Rkt](https://coreos.com/rkt/): Tailored for cloud-native environments, Rkt emphasizes application containerization and modern production capabilities.

- [LXC and LXD](https://linuxcontainers.org/): LXC facilitates a vendor-neutral environment for Linux container development, while LXD manages and enhances the user experience with Linux containers.

**Docker** is the most popular one and hence, in my next [article](https://dev.to/denzubechi/concepts-of-docker-3je9), you will learn to create containers using the Docker engine.😎 🥳

Now let's learn more about the differences between containers and VMs.

![VMs vs Containers](https://www.veritis.com/wp-content/uploads/2019/08/containers-vs-virtual-machines-vm.jpg)

### What is a VM?🧐
A **Virtual Machine (VM)** is comparable to a complete computer, functioning with its own operating system and virtualized hardware. Like containers, a host machine can run multiple VMs to scale isolated applications effectively. However, VMs require significant resources since they virtualize an entire machine, making them somewhat resource-intensive. This is where containers present a compelling advantage.

- When managing multiple VMs on a host machine, each VM operates with its independent operating system. The host OS oversees these VMs using a hypervisor, specialized software responsible for creating and managing the VMs while ensuring their isolation from each other.
- Conversely, containers package an application along with its dependencies, without requiring a separate OS or virtualized hardware. Instead, containers share the underlying host operating system kernel. In practice, a container manager takes care of managing the containers, serving a role akin to that of a hypervisor in the VM scenario.

In essence, VMs offer strong isolation, simulating complete machines but come with higher resource overhead. On the other hand, containers leverage shared resources and lightweight isolation, making them more efficient and agile. Containers' streamlined approach significantly simplifies the management and scaling of applications, making them an increasingly preferred solution in modern software development and deployment scenarios.

### How to create VMs? 🧑‍🔧 
To set up Virtual Machines (VMs), you can utilize specialized software known as Hypervisors. These Hypervisors allow you to create complete computers, each with its own operating system and virtualized hardware. Here are some popular Hypervisors you can use locally:

- [Microsoft Hyper-V](https://docs.microsoft.com/en-us/virtualization/hyper-v-on-windows/quick-start/quick-create-virtual-machine)
- [Oracle VM VirtualBox](https://www.virtualbox.org/manual/ch01.html)
- [VMware](https://www.vmware.com/)
- [Parallels Desktop](https://www.parallels.com/)

Each Hypervisor comes with its unique features, allowing you to create and manage VMs tailored to your needs. However, in this course, we won't dive into the specifics and various types of Hypervisors, as it goes beyond our current scope.

Additionally, if you prefer a cloud-based approach, leading cloud service providers like [AWS](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/concepts.html), [GCP](https://cloud.google.com/compute/docs/instances), and [Azure](https://azure.microsoft.com/en-in/services/virtual-machines/) offer Infrastructure as a Service (IaaS) options. They allow you to create VMs on their cloud infrastructure, providing flexibility, scalability, and ease of management.

Though the details of VM creation are not covered in this tutorial, it's crucial to grasp the relative distinctions between containers and VMs. Containers offer lightweight, efficient, and consistent application packaging, sharing a single host operating system kernel. VMs, on the other hand, virtualize complete machines with their independent OS, providing strong isolation but potentially consuming more resources.

Understanding these differences will help you make informed decisions on when to use containers or VMs, depending on your specific application requirements and deployment scenarios.

### Problems with VMs 😔💔
As we've explored before, a Virtual Machine (VM) functions like a self-contained computer, operating with its individual copy of an operating system and virtual hardware. While VMs effectively scale applications, their drawback lies in their resource-intensive nature since they replicate an entire machine virtually. However, there is a more efficient alternative for scaling up your applications – containers.

Containers offer a significant improvement over VMs in terms of resource utilization and scalability. Unlike VMs, containers don't require a complete OS or virtualized hardware. Instead, they bundle an application together with its dependencies, sharing the host operating system kernel. This lightweight approach reduces resource overhead and accelerates performance, making containers a preferred choice when scaling applications.

By leveraging containers, you can achieve a streamlined and more agile deployment process. The ability to rapidly create, distribute, and manage containers empowers developers to scale applications effortlessly without the resource burdens associated with traditional VMs.

In summary, containers offer an efficient and powerful solution for application scaling, making them an ideal choice when you seek to optimize resource usage and enhance your development and deployment workflows.


### Summary: Benefits of using Containers versus VMs 📌👌🏽
In comparing Containers to Virtual Machines (VMs), we find several compelling benefits that containers offer:
- **Size**: Containers are significantly smaller in size compared to VMs. While VMs can occupy several gigabytes of storage, containers are typically in the megabytes range. This reduced size makes it easier to store, transfer, and deploy containers efficiently.

- **Speed**: VMs can be relatively slow to start up and may take minutes to launch fully. In contrast, containers boast impressive speed and responsiveness, often launching in a matter of seconds. This rapid startup time allows for quicker application deployment and scalability.

- **Composability**: Containers are designed with a focus on programmable creation, defined as source code. They can be built, deployed, and managed programmatically, promoting a more flexible and automated approach to application development and deployment. In contrast, VMs often replicate conventional computer systems, leading to less agility in certain scenarios.

In essence, containers present a more lightweight, nimble, and programmable alternative to VMs. Their compact size, speedy boot times, and composability make them an attractive choice for modern software development and deployment, particularly when seeking rapid scalability and streamlined workflows.

## Let's wrap it up 🎁
In this tutorial, you discovered the power of containers, ensuring environment consistency for smooth deployment from development to production. You learned the differences between VMs and containers, and how containers revolutionize your DevOps workflow. Let containers be your key to faster, more efficient, and scalable software development. 

Happy Coding and Thank you for reading! 🎉!