Everything You Should Know About Containers
Picture this: a revolutionary technology that enables seamless, efficient, and scalable deployment of applications across diverse environments. Join me as we discuss the advantages of this innovation
Containers
Many technological tools have revolutionized the way we build software products. Some major ones include Artificial Intelligence and Machine Learning, Cloud Computing, Internet of Things, Blockchain etc. However, one major one that is often overlooked is the introduction of containers and containerized applications. I believe that before using containers, software development teams were in the dark ages. Chaos, multiple bugs, and errors, non-compatibility issues, and long deployment times would characterize a team before containers. Although things worked well with Virtual Machines and Hypervisors, which could be said to be the foundational idea for container technology, containers solved a lot of issues and pushed DevOps practices and culture into the forefront of software development.
Now, what are containers?
I’m sure many have heard of containers but might not clearly understand what they are and how much of an advantage containerization is to development and deployment.
So here is a simple illustration; imagine you are a chef and you own your restaurant. You are doing great and business is really good. Customers come into your restaurant, order their meal, prepare the special dish, and serve it to them at their table hot and steaming on their plates just the way they like it. But with the new age of working from home, most of your customers no longer come into the restaurant and you now have to deliver their food to their location or you go out of business. To do this, you must find a way to keep the food intact and perfect from the kitchen where the meal is prepared to where it is delivered to your customer, still hot and steaming, just the way they like it. But how? You can’t serve it to them on a plate anymore, you now need a container. A container would help you package your food in the right environment to prepare it for the customer.
In software development, an application can run perfectly in one environment that has all the requirements of the application but fails in another environment because there are likely different configurations between the two environments. Containers provide a means for you to create a package of an application containing everything the application needs to be perfect in any environment. Just like the example of our chef who needs the food to remain perfect from his kitchen to his customers' table.
Difference between Containers and Virtual Machines
Before the advent of containers, most applications were deployed on virtual machines. Applications were developed, built, packaged, and then deployed as processes or a collection of processes running on virtual machines. There are still some cases where applications are deployed on virtual machines or hypervisors today, but this method of deployment tends to create compatibility issues and other bugs and errors.
What are containers?
Containers are portable, lightweight executable images that contain applications and all the dependencies needed to run the application within the image. A single container image can contain executables, binary code, libraries, and configuration files required by an application while still being lightweight and portable. This makes them very suitable for running microservices of applications.
What are virtual machines?
Virtual machines on the other hand refer to an abstraction of hardware resources of physical machines that allow you to run separate guest operating systems. Virtual machines make use of a hypervisor to access the physical hardware resources of a machine, this allows different VMs to make use of different abstractions of the memory, storage, and CPU.
Differences
Virtual machines and containers are used for deploying and running applications. However, there are various approaches to how the deployments are handled. Whereas containers share the same operating systems on the same host and are separated in the container runtime, virtual machines are separate instances of operating systems on the host machine, and applications and services are run within these operating systems.
Benefits of Containers
Some of the advantages that using containers offer are:
Efficient Resource Utilization: Containers don’t require an operating system in their image to run applications. This vastly optimized their use of system resources when compared to virtual machines and other forms of deployment environments
Consistent Application Behavior: With containers and images, an application is built with all its requirements and can run the same way in any kind of environment
Increased Portability: Containerized applications can be deployed and managed easily to different operating systems and hardware platforms
Speed: Containers are much faster to create and start up when running applications
Better Application Deployment: Containers are a fundamental part of DevOps practices and they help improve software development processes.
Use Cases of Containers
Containers are very suitable for a wide range of use cases. Some of them include:
Web Development: Containers can easily be deployed to various environments seamlessly. This makes them very suitable for web development.
Microservice Architecture: In a microservice architecture, various components of the application are deployed as loosely coupled, isolated services. Containers are the best medium of deployment for these component's services
CI/CD: The various tasks involved in a ci/cd process such as automation, testing, builds, and deployment processes are best carried out in lightweight environments and containers are most suitable for these processes
Background Jobs and Repetitive tasks: Repetitive tasks, background tasks, and time tasks are best run on lightweight engines because they need specific requirements and often minimal resources. Tasks such as ETL jobs, batch jobs, cron jobs, etc are best run on containers.
Use Cases of Virtual Machines
Virtual Machines are usually used when there is a need to set up an entire machine infrastructure where other applications or containers can run. If you need complete isolated environments to run your workload for development, testing, production, and disaster recovery, then setting up separate virtual machines with their separate operating systems would be best for you. In cases like this, a lightweight, easily disposable machine like a container would be a high-risk environment for your workload. Some of the use cases of virtual machines include:
Disaster Recovery Sites
Testing Environment
Development Environment
Managing Containers
In real-world applications of containerization, it is often the case that an application (usually a microservice application) would need multiple containers to run its operations. It is important to have a way to manage and provide administrative for the containers. Many container orchestration tools can be used to manage containers. Some include:
Docker Swarm
OpenStack
Kubernetes
Containers and containerization are very important concepts in software development and infrastructure engineering. A Software Engineer or DevOps Engineer needs to practice working with tools like this and see how they improve the efficiency of your projects and your workflow. Tools like Docker and Kubernetes should be an important part of your home lab as well. Find out more about how you can set up your home lab for personal projects and practical experience with various tools in this article:
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