What is Kubernetes, and How to Use It?
For those of you not closely familiar with the subject, please allow us to define the matter in more detail to make sure everyone is on the same page.
Overview of Kubernetes
Turning a little bit back in history, Google open-sourced the Kubernetes project in 2014, and K8s effectively turned into a rapidly growing ecosystem, making its services, support, and tools widely available to all stakeholders involved.
The actual roots of the ecosystem lead to the Greek language, meaning helmsman or pilot, whereas K8s abbreviation resulted from counting the eight letters between the “K” and the “S.” Overall, Kubernetes mobilized and united over 15 years’ worth of ideas and efforts contributed by Google teams and their hands-on experience, in running production workloads at scale.
And yet, talking of definition, Kubernetes is a portable, extensible, open-source platform for managing containerized workloads and services that facilitate declarative configuration and automation.
In other words, Kubernetes is an open-source container orchestration platform that automates many of the manual processes involved in deploying, managing, and scaling containerized applications.
Thus, the fundamental idea of Kubernetes is to further abstract machines, storage, and networks away from their physical implementation. Hence, it is a single interface to deploy containers to all kinds of clouds, virtual machines, and physical machines. Yet, we will dive deeper into this at a slightly later stage.
However, to fully understand the rationale behind such an approach, we suggest taking a little walk back in time.
What is the Use of Kubernetes: Rather Useful, K8s Really is!
We should split deployment into three different eras, beginning with traditional deployment. Those days, organizations used to run applications on physical servers (in fact, many still do so these days). The massive limitation of such an approach is that it is impossible to define resource boundaries for applications within those physical servers. That is to say that allocation conflicts were an ongoing issue, causing significant troubles when it came to the use of multiple apps on one server.
In particular, in such cases, one application could easily consume almost all of the server’s resources, leaving other apps with no choice but underperform. Some of you may remember those days, and the only solution was to employ a single server to perform the needs of a single app. And given that there were a number of apps, organizations were forced to maintain a number of physical servers, which was significantly resource consuming and did not really provide any scale as overall, resources were underutilized.
Nothing lasts forever, and a solution of virtualized deployment was suggested and introduced. Again, it should be admitted that this approach remains quite a force these days as it suits all kinds of stakeholders. Technically speaking, a single vervet’s CPU allows to run multiple numbers of Virtual Machines, probably more known as VPS (Virtual Private Server) often provided by a third-party offshore hosting provider like, for instance, VSYS.
Such a degree of virtualization allows resources to be isolated between Virtual Servers (that is not to say that the whole physical server can still be dedicated to the needs of a single client or shared with respect to their particular needs). Anyways, the level of security was significantly raised so that one app couldn’t be freely accessed by another one.
There are numerous perks that come with virtualization, ranging from better utilization of physical sever’s resources to significant and almost instant scalability further reinforced by noticeable reduction of hardware costs and maintenance expenses. In addition, with virtualization, you can present a set of physical resources as a cluster of disposable virtual servers, whereas each VS features its own operating system on top of the virtualized hardware.
It’s crucial to develop APIs fit for purpose in today’s world. Cloud-native application development relies on connecting a microservices application architecture through your APIs to share data with external users, such as your customers. In a way, classic clouds are VPSs managed using APIs.
Finally, the container deployment era has arrived at our doorstep. Technically speaking, containers are pretty similar to VSs, but they have relaxed isolation properties to share the Operating System (OS) among the applications. Thus, containers are considered lightweight and being very similar to Virtual Servers. Containers feature share of CPU, process space, available memory, and shave their own file system. Importantly, containers are portable across clouds and OS distributions, thanks to being decoupled from the underlying infrastructure.
What is Containerization in Kubernetes?
K8s unites several concepts so that before we can explain what Kubernetes does, we need to explain what containers are and why people find them useful and usable.
Putting it bluntly, a container is a mini-virtual server. No need to mention the benefits of VSs we’ve identified to this point. The reason for naming it mini as it does not have device drivers and all the other components of an ordinary virtual machine.
Talking of popularity, Docker is undoubtedly the most popular container today. Mind you, it was written for Linux, whereas Microsoft has also provided containers for Windows. That is a tribute to their popularity.
However, a practical example from industry experts should help the most to prove the above point.
Let’s imagine you want to install the Nginx web server on a Linux server. Probably, you can think of a number of ways to tackle this task. The most obvious one is to install it directly on the physical server’s OS. Although, given that virtual servers are rising in popularity and are more practical, it makes sense to install it right there.
So far, so good but, bearing in mind the very need to make sure that the virtual server is not underutilized being dedicated to one task only as well as minimize admin costs and other efforts. Hence, it would be better to load that one machine up with Nginx, messaging software, a DNS server, etc.
Great minds behind container invention have thought about this and suggested that since Nginx or any other application just needs some bare minimum operating system to run, then why not make a stripped-down version of an OS, put Nginx inside, and run that. Voila, you have a self-contained, machine-agnostic unit that can be installed anywhere.
To sum up, there is a chance of containers eventually replacing virtual servers due to their more significant popularity and practical implementation.
Infrastructure as Code: Kubernetes
Worth mentioning that infrastructure as Code (IaC) means that you use code to define and manage your infrastructure automatically rather than with manual processes. With IaC, you can automatically build, deploy and manage your infrastructure much more effectively and reliably than you can manually.
Kubernetes has been around for a few years now, and it has enabled having your infrastructure written as a code. This is a tremendous benefit in two ways: your infrastructure can now be versioned and committed to a Git repository, and your infrastructure can easily be “deployed” elsewhere.
What is Kubernetes Architecture and How Does it Work?
The Kubernetes architecture is designed to run containerized applications. Frankly speaking, containers encapsulate an application in such form to make it portable and easy to deploy. A Kubernetes cluster consists of at least one control plane and at least one worker node (typically, these are physical or virtual servers, respectively). In its turn, the control plane has two primary responsibilities. It exposes the Kubernetes API through the API server and manages the nodes that make up the cluster. The control plane makes decisions about cluster management and detects and responds to cluster events.
Please note that the smallest unit of execution for an application running in Kubernetes is the Kubernetes Pod, which consists of one or more containers. Kubernetes Pods run on worker nodes.
Core Kubernetes Concepts
The following concepts should further clarify how Kubernetes operates and what it does.
A node is a physical or virtual machine. It is not created by Kubernetes. You create those with a cloud operating system or manually install them. Thus you need to lay down your basic infrastructure before you use Kubernetes to deploy your apps. Although, from that point, it can define virtual networks, storage, etc.
A pod is one or more containers that logically go together. Pods run on nodes. Pods run together as a logical unit. So they have the same shared content. They all share the share IP address but can reach one another via localhost. And they can share storage. But they do not need to all run on the same server as containers can span more than one server. One node can run multiple pods. Pods are cloud-aware.
A set of pods is a deployment. A deployment ensures that a sufficient number of pods are running at one time to service the app and shuts down those pods that are not needed.
Even though it was invented by Google, Google is not said to dominate its development. Kubernetes works with many cloud and server products. And the list is constantly growing as so many companies are contributing to the open-source project.
What are Kubernetes Container Benefits?
Please allow us to summarize those extra benefits provided by containers:
- K8s containers provide agile application creation and deployment
- Continuous development, integration, and deployment
- Dev and Ops separation of concerns
- Environmental consistency across development, testing, and production.
- Cloud and OS distribution portability
- Application-centric management
- Resource isolation, high efficiency, and full utilization
- Auto-scaling responding to usage requirements
- Lifecycle management being able to roll back, pause, and continue deployment
- Resilience and self-healing
- Persistent storage
- Load balancing
- DevSecOps support. DevSecOps is an advanced approach to security that simplifies and automates container operations across clouds, integrates security throughout the container lifecycle, and enables teams to deliver secure, high-quality software more quickly. Combining DevSecOps practices and Kubernetes improves developer productivity.
To wrap up the benefits, please allow us to step further and provide you with the advantages Kubernetes offers its fire-breathing partisans.
Use of Kubernetes Leads to Major Advantages
For sure, Google’s name standing behind Kubernetes provides a great degree of credibility, yet, the K8s platform itself provides quite tasty bonuses:
Portability is something, to begin with, suggesting that K8s containers are portable across all sorts of environments ranging from virtual environments to bare metal. Moreover, Kubernetes is supported in all major public and private clouds so that K8s containerized applications can run across very different environments.
Furthermore, Kubernetes stand for Integration and extensibility. In particular, K8s is extendable to work with the solutions already in use, including logging, monitoring, and alerting services. Don’t forget that the Kubernetes community is working on a variety of open source solutions complementary to Kubernetes, creating a rich and fast-growing ecosystem.
K8s saves money, say nothing of its cost efficiency achieved via inherited resource optimization, automated scaling, and flexibility to run workloads, placing you in total control of your spending.
Another major factor is scalability. Kubernetes uses “auto-scaling,” spinning up additional container instances and scaling out automatically in response to demand, whereas cloud-native applications scale horizontally.
It is essential to remember that K8s is API-based, making REST API the fundamental fabric of Kuberneteand, allowing for programming control of literally everything within the Kubernetes.
Last but not least is simplified CI/CD. CI/CD is a DevOps practice that automates building, testing, and deploying applications to production environments. Enterprises are integrating Kubernetes and CI/CD to create scalable CI/CD pipelines that adapt dynamically to load.
he primary strength of Managed Kubernetes is its modularity and generality. Kubernetes is an excellent tool for orchestrating containerized applications. It automates the very complex task of dynamically scaling an application in real-time. Nearly every kind of application that you might want to deploy you can fit within Kubernetes, and no matter what kind of adjustments or tuning you need to make to your system, they’re generally possible.
The problem with K8s is that it’s a complex system itself, so you may need to involve someone with professional expertise in the area, allowing you to focus on your project. VSYS is always happy to serve this role for you.