Introduction to Kubernetes on vSphere (Part 1)

Introduction

Kubernetes is an open-source container orchestration platform for managing containerized applications. Almost all enterprises use VMware’s virtualization platforms when it comes to implementing their IT infrastructure. As containers become more common, a growing requirement is deploying containers alongside traditional virtual machines and managing them alongside traditional virtual machines.

Containers were first introduced on Linux in 2008 as a lightweight & portable platform for distributing and running applications across operating systems and clouds. In 2019 VMware began supporting Kubernetes within its vSphere virtualization platform, which includes the ESXi hypervisor.

By being lightweight, containers don’t have the same boundaries – security, and performance – as virtual machines. The development of applications can be greatly enhanced by using containers. A key feature of Kubernetes is its ability to automate and orchestrate deployments and availability, which makes it ideal for managing many challenges associated with deploying those applications.

Kubernetes is an open-source project that is governed by the Cloud Native Computing Foundation. It is a platform for managing containerized workloads and services, which facilitates both declarative configuration and automation of workloads, and is defined as a portable, extensible, and open-source platform. In addition to contributing heavily to open-source Kubernetes software, VMware has also actively participated in Kubernetes communities and governance.

Due to Kubernetes’ API-driven nature, automation is a breeze. As application developers strive to implement modern development practices, short or continuous development cycles, well-defined APIs, and separated and defined services, such as microservices, it is very attractive.

In today’s IT infrastructure and governance environment, vSphere and Virtual Infrastructure administrators often find themselves positioned between developers seeking to implement modern application development practices and more traditional practices rooted in decades of IT experience. We are posting this guide to help administrators understand what vSphere with Kubernetes is, how it helps build bridges between applications, and how to start using it both on-premises and in the cloud.

Figure 1: Image Source VMware blogs

What is Kubernetes?

It has a large, rapidly growing ecosystem. Kubernetes services, tools, and support are widely available. Kubernetes is a portable, extensible, open-source platform for managing containerized workloads and services.

Application development and deployment are being revolutionized by container orchestration tools such as Kubernetes. Development teams are becoming more focused on delivering value through software with the growth of microservices architecture and decoupling infrastructure from application logic.

What does Kubernetes mean to a VMware Administrator?

Using Kubernetes, modern, container-based workloads can be orchestrated and managed throughout their lifecycle. To better understand how Kubernetes fits into the modern enterprise, perhaps we should look at the history of the different approaches to application deployment:

Figure 2: Deployment Type

Traditional Deployment Era

The traditional deployment method is to deploy applications and workloads directly to physical servers. These types of deployments tend to be inflexible, hard to scale, and waste resources by tying them to specific systems. For Example, if multiple applications run on a physical server, there can be instances where one application takes up most of the resources, and as a result, the other applications suffer. There would be a solution to this if each application were run on a separate physical server. Organizations were unable to scale this because resources were underused, and maintaining many physical servers was expensive.

Virtualized Deployment Era

To fix the traditional deployment problem, virtualization was introduced. A new deployment type allows multiple virtual machines to run on a single physical server. Since the VM was isolated, applications could not easily access other applications on different VMs. The cost of hardware and other expenses can be reduced due to the efficient use of resources on physical servers. In addition, it is easier to add and update applications as well, which helps reduce operational costs.

By mimicking the functions of a physical server with a hypervisor such as VMware ESXi workloads can appear as if they are running on them. As well as vMotion, and dynamic resource scheduling VMware ESXi provides many other features that make it an attractive alternative to traditional workload deployment

Containerized Deployment Era

Containers are like Virtual Machines but are lightweight; the fundamental difference lies in their isolation properties as well as it doesn’t have rigid boundaries which VM has. Because containers share the operating system (OS), they are ultralightweight.  In contrast, containers have their filesystems and resource allocation mechanisms since they are decoupled from the underlying infrastructure. Containers can run on multiple cloud providers as well as running on different operating systems. The lightweight nature of containers makes continuous development and integration for deployment possible, a capability that makes containers popular.

Kubernetes Deployment

Kubernetes is a powerful container management tool that automates container deployment and management. Running containers in production requires the deployment, management, and updating of thousands of containers, if it is done manually, it would require a large team and long hours. Kubernetes users can now consume services in a VMware environment like using public cloud service. VMware vSphere can now manage workloads uniformly, regardless of whether they are containers, applications, or virtual machines.

vSphere with Kubernetes

At VMworld 2019, VMware announced vSphere with Kubernetes as Project Pacific. In Addition to adding Kubernetes capabilities to vSphere, respect the traditional vSphere experience of developers and administrators.

To a Developer, it works like a standard Kubernetes cluster with the same tools and processes, Kubernetes is based on a declarative syntax for defining resources such as storage, network, scalability, and availability. It eliminates developers’ need to directly access vSphere APIs or infrastructure and even relationships between entities.

To a vSphere Administrator, Kubernetes clusters for VMware can provide developers with a way to manage security, resource consumption, and networking functions using namespaces (used in Kubernetes for policy and resource management). Vsphere Administrators can manage the security, resource consumption, and networking capabilities available to developers by deploying “namespaces”, which are Kubernetes terms for managing resources and policies.

Figure 3: vSphere with Kubernetes

With vSphere and Kubernetes, you can host both traditional workloads and modern, cloud-native applications. For developers, it’s Kubernetes. For administrators, it’s vSphere. For Business-critical workloads along with modern, cloud-native applications are deployed and managed seamlessly while IT infrastructure security and compliance are maintained.

How does Kubernetes work with vSphere?

In vSphere, you will find a Kubernetes API, with a control panel based on the namespace entity managed by administrators, providing cloud service like a public cloud. This architecture enables consistent orchestration and management no matter what form or shapes the workload takes – container, virtual machine, or application.

Spherelet and Pod Service

With Spherelet, a customs agent from vSphere, Kubernetes API can be accessed directly from the ESXi hypervisor. Kubelet agent allows the ESXi hypervisor to connect with the Kubernetes cluster locally by acting as a local Kubernetes node.

A Linux VM or instance doesn’t need to be run separately on this hypervisor for containers to be hosted. From Kubernetes’s perspective, vSphere Pods services appear as vSphere containers running on ESXi which is called CRX (Container Runtime for ESXi).

Supervisor

In the Supervisor, the Spherelet agent is integrated directly into the ESXi hypervisor as a worker node instead of Linux, a special Kubernetes cluster type. Direct integration of the spherelet agent with the hypervisor ESXi is performed for this purpose.

In vSphere Pods, the Spherelet runs directly on ESXi, taking advantage of the hypervisor’s high availability, security, and performance.

Tanzu Kubernetes Cluster

Its production-grade operational capabilities make it highly suitable for support in large Kubernetes deployments. Tanzu Kubernetes Grid Integrated Edition is VMware’s first Kubernetes – first infrastructure solution. With TKG (Tanzu Kubernetes Grid), the infrastructure layer and the application layer of Kubernetes are managed together.

Conclusion

The combination of vSphere and Kubernetes allows VMware Administrators to remain familiar with the traditional vSphere environment while also delivering a world-class environment for containerized workloads.

It can be challenging to install and operate open-source Kubernetes. It’s like nothing else in the industry brings Kubernetes to enterprises like VMware vSphere with Kubernetes and the VMware Cloud Foundation. These products help businesses position themselves for the future without sacrificing current investments by leveraging existing infrastructure, people, processes, and workloads.

With Kubernetes namespaces, we can manage applications inside virtual infrastructure in a whole brand-new way. The sets of operational and security boundaries, but the developers get freedom and self-service. As with namespaces, Kubernetes orchestrates deployment, availability, security, and other operational details for workload administrators, developers, and VMware administrators.

Kubernetes clusters come in different flavors in VMware vSphere with Kubernetes. While Supervisor Clusters are tightly integrated with vSphere, they’re not as secure and performant as Kubernetes. When it comes to lifecycle operations, Tanzu Kubernetes Clusters are more flexible and conform to upstream Kubernetes releases.

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