Kubernetes: Everything You Need to Know


Kubernetes is the leading container orchestration system. It is a tool that facilitates the automation of all aspects of application deployment and management. Kubernetes plays a key role within the world of cloud applications. The platform accelerates time to market, offers enhanced scalability and availability, combines neatly with cloud optimization tools, works flexibly across multiple and hybrid cloud environments, and makes all aspects of cloud migration smoother.

Containers: A Brief Overview

To understand Kubernetes, you first need to understand containers.

cloud containers

Back in 2013, Docker changed everything. Building on existing virtualization technologies, Docker introduced containers. A container is an abstraction, implemented at the kernel level, that consists of an entire runtime environment. This means that a container contains an application, but it also contains all of its dependencies, libraries and configuration files.

Containers allow you to quickly and smoothly move software from one computing environment into another. (For example, from staging to production, or from a physical server to a virtual machine (VM).) By “containerizing” an application and its dependencies, differences in infrastructure or OS distributions are abstracted away. An app will run the same on your laptop as it does in the cloud.

Unlike with older virtualization and VM frameworks, containers are able to share an operating system kernel with one another thanks to their relaxed isolation properties. As a result, a container is considerably more lightweight than a VM (virtual machine), which typically contains its own dedicated OS. This means that servers can host many more containers than it can VMs.

Containers are integral to modern DevOps frameworks. Their modular nature is what allows for a microservices approach, where different parts of an app are split up across different containers. Containers allow for quick and easy rollbacks, due to their image immutability. Containers accelerate the time-to-value for code, allowing releases to arrive daily, rather than quarterly. In modern cloud computing, containers are fast becoming the new norm. The 2019 Container Adoption Survey found that 87% of respondents used container technologies, compared to just 55% back in 2017. 451 Research predicts that containers will be a $4.3-billion industry by the end of 2022.

Container Organization: Kubernetes to the Rescue

What is Kubernetes exactly?

But: Containers need to be managed. They are complex entities, and many DevOps teams are managing thousands of containers. 

Enter Kubernetes. Originally designed by Google, Kubernetes (pronounced “koo-ber-NET-eez”) is an open-source container orchestration software designed to simplify the management, deployment, and scaling of containerized applications. Also referred to as “K8s”, “Kube”, or “k-eights”, Kubernetes is actually the Greek word for helmsman – the person in charge of steering a ship. Kubernetes integrates with a range of container tools, but the majority of people pair it with Docker. 

In short, Kubernetes is what people use to manage their containers. Kubernetes automates and simplifies the various processes involved in the deployment and scaling of containers, as well as in directing traffic into and between containerized applications. In a production environment, enterprises need full control over the containers that run their applications, to ensure that there is no downtime. Kubernetes gives them this level of control. 

Kuberenetes also facilitates the efficient management of clusters of containers. Kubernetes clusters can be distributed across multiple environments, including on-premise, public, private, or hybrid clouds. This makes Kubernetes an ideal hosting platform to manage cloud-native applications that rely on rapid, real-time scaling (such as data streaming through Apache Kafka).

How Kubernetes Works: Some Technical Details

From a 30,000-foot level, Kubernetes provides DevOps reams with a framework to run distributed networks of containers resiliently. Kubernetes enables flexible and reliable scaling of large clusters of containers, provides failover for applications, provides deployment patterns, and everything else teams need.

The base of the Kubernetes architecture consists of the containers that communicate with each other via a shared network. These containers form into clusters, where several components, workloads, and capabilities of the Kubernetes environment are configured.

Every node in every cluster is provided a specific role within the Kubernetes infrastructure. One particular node typeis deployed as the master node. The master server is the cluster’s main point of contact. It is in charge of the majority of the centralized logic that Kubernetes supplies  This is basically the gateway and brain for the cluster. The master server reveals an API for both clients and users, monitors the health of other servers, identifies the best ways to split up and delegate work, and facilitates and organizes communication between other components. In highly available Kubernetes clusters, there are multiple master nodes (typically 3) in order to ensure that the cluster can be contacted and continues to operate even if a master node fails. Kubernetes arranges for the automatic failover between master nodes.

Worker nodes are tasked with accepting and running workloads. To ensure isolation, efficient management, and unmatched flexibility, Kubernetes places and runs applications and services in containers. A container runtime (like Docker or rkt) needs to be equipped per node for this setup to work.

Once everything is up and running, the master node sends work instructions to the worker nodes. Fulfilling these instructions, worker nodes stand up or tear down containers accordingly, make adjustments to the networking rules to route and direct traffic appropriately.

Quick Definitions of Kubernetes Key Elements

Master node. Functions as the main control and contact point for administrators and users. It also distributes (schedules) workloads to worker nodes and handles failover for master and worker nodes.

Worker nodes. Act on assigned tasks and perform requested actions. Worker nodes take their instruction from the master node.

Pods. A group of containers that share network and storage and are alwaysplaced in a single node. Containers within the same pod typically collaborate to provide application’s functionality and are relatively tightly coupled.

Replication controller. This provides users with total control over the number of identical copies of a pod operating on the cluster.

Service. A named abstraction that exposes an application running on a set of pods as a network service and load balances traffic among the pods.

Kubelet. Running on nodes, Kubelet takes the container manifests, reads them, and ensures the defined containers are activated and functioning.

kubectl. The command line tool for controlling Kubernetes clusters.

The Business Advantages of Kubernetes

Kubernetes brings obvious benefits when viewed from an IT or DevOps perspective. But how does Kuberentes positively impact the business goals of an enterprise? In five key ways:

1. Accelerated time to market.

Kubernetes allows enterprises to utilize a microservices approach to creating and developing apps. This approach enables companies to split their development teams into smaller groups, and achieve more granular focus on different elements of a given app. Because of their focused and targeted function, smaller teams are more nimble, and more efficient.

Additionally, APIs between microservices reduce the volume of cross-team communication needed to build and deploy apps. Teams can do more, while spending less time in discussions. Businesses can scale different small teams composed of experts whose individual functions help support thousands of machines.

Because of the streamlining effect of the microservices model that Kubernetes empowers, IT teams are able to handle huge applications across many containers with increased efficiency. Maintenance, management, and organization can all be largely automated, leaving human teams to focus on higher value add tasks.

2. Enhanced scalability and availability.

Today’s applications rely on more than their features to be successful. They need to be scalable. Scalability is not just about meeting SLA requirements and expectations; it’s about the applications being available when needed, able to perform at an optimum level when activated and deployed, and not swallowing up resources that they don’t need when they are inactive.

Kubernetes provides enterprises with an orchestration system that automatically scales, calibrates, and improves the app’s performance. Whenever an app’s load requirements change – due to an increasing volume of traffic or low usage – Kubernetes, with the help of an autoscaler, automatically changes the number of pods in a service in order for the application to remain available and meet the service level objectives at the lowest cost.

For instance, when concert ticket prices drop, a ticketing app experiences a sudden and large spike in traffic. Kubernetes immediately spawns new pods to handle the incoming load that is above the defined threshold. Once the traffic subsides, Kubernetes scales down the app back to configurations and metrics that optimize infrastructure utilization. In addition, Kubernetes’ auto-scaling capability not only relies on infrastructure metrics to initiate the scaling mechanism. It scales automatically using custom metrics as triggers to the scaling process.

3. Optimization of IT infrastructure-related costs.

Kubernetes reduces all expenses pertaining to IT infrastructure drastically, even when users are operating on a large scale. The platform groups apps together using hardware and cloud investments, and runs them on a container-based architecture.

Prior to Kubernetes, administrators addressed the instances of unexpected spikes by ordering tons of resources and putting them on reserve. While this helps them handle unforeseen and unpredicted increases in load, ordering too many resources quickly becomes extremely costly.

Kubernetes schedules and solidly packs containers, while taking into consideration the available resources. Because it automatically increases or decreases the load on applications based on prevailing business requirements, Kubernetes helps enterprises free up their manpower resources, which they can then assign to other pressing tasks and priorities.

4. Flexibility of multiple cloud and hybrid cloud environments.

Kuberentes helps enterprises to fully realize the absolute potential of multiple and hybrid-cloud environments. That’s a big plus, considering the number of modern companies running multiple clouds is increasing every day.

With Kubernetes, users find it much easier to run their app on any public cloud service or in a hybrid cloud environment. What this means for enterprises is they can run their apps on the most ideal cloud space, with the right-sized workloads.

This helps them avoid vendor lock-in agreements, which typically come with specific requirements around cloud configurations and KPIs. Getting out of lock-in agreements can be expensive, especially when there are other options that are much more flexible, more cost-effective, and have a bigger ROI, over both the short and long term.

5. Effective cloud migration.

Whether a Kubernetes user requires a simple lift and shift of the app, making adjustments to the app runs, or a total overhaul of the entire app and its services, migrating to the cloud can be a tricky enterprise, even for experienced IT professionals. But Kubernetes is designed to make such cloud migrations much easier.

How? Thanks to the nature of containers, Kubernetes can run across all environments consistently, whether on-premise, cloud, or hybrid. The platform supplies users with a frictionless and prescriptive path to transfer their on-premise applications to the cloud. By migrating via a prescribed path, users don’t have to face the complexities and variations that usually come with the cloud environment.

The Future of Kubernetes

For the moment, enterprise organizations are chiefly using Kubernetes because it is the best way to manage containers, and containers supercharge the possibilities of app creation and deployment. Kubernetes automates processes that are critical to the management of IT infrastructure and app performance, and helps organizations optimize their cloud spend.

The future of Kubernetes could get even more interesting. Chris Wright, VP and CTO of Red Hat, summarizes the new ecosystem that is emerging around Kubernetes: “Just as Linux emerged as the focal point for open source development in the 2000s, Kubernetes is emerging as a focal point for building technologies and solutions.”

Kubernetes is currently the leading container orchestration platform. But increasingly, it is doing more than simply enabling organizations to manage their containers, optimize their cloud apps, and reduce spend. Kubernetes is actually driving new forms of “Kubernetes-native” app and software development. As the shift toward microservices continues to pick up pace, organizations will create and deploy apps with Kubernetes in mind from the jump – as a formative influence, not merely a tool.