Kubernetes is a leading tool for deploying and managing large containerized applications. As a result, it’s no surprise that more and more enterprises are using Kubernetes as their primary tool for managing and operating large-scale, containerized applications. In this blog post, you’ll learn everything you need to know about Kubernetes, the Containers they manage & why Kubernetes is right for your organization.
Before we dive into the ins and outs of Kubernetes, let us first briefly go over the concept of Containers.
Before Kubernetes, let’s discuss Containers
Containers are lightweight, self-contained units of software that can be launched and managed as individual processes. Containerization is the process of packaging an application into a container and shipping it across the network. It allows applications to be shipped from Development to Production without changes or recompiling.
The two most frequently used mechanisms to host applications in a computer system are Containerization and Virtualization. Unlike Containerization, which involves encapsulating an application in a container with its own operating environment, virtualization uses the notion of a virtual machine as the fundamental unit, having an independent OS for each virtual machine.
Containers Vs Virtual Machines (VMs)
- Containers are small, fast, and portable. Unlike a VM, containers do not have to include the guest OS on each instance and instead can just leverage features and resources from the host operating system. Because containers generally share an operating system kernel and do not have the overhead of having an entire operating system inside of each container, they are generally considered more lightweight compared with virtual machines (VMs).
- VMs allow an organization to run several virtual servers – no matter what the OS is – on the same piece of hardware. However, containers offer a means to virtualize the OS in order to run multiple workloads on the same OS instance.
- Containers provide light, high-density application virtualization, the ability to turn applications and instances on and off in seconds, and a certain level of security that comes from having individual applications within their containers. As the name suggests Virtual Machines provide complete isolation from the host operating system and the other VMs.
Kubernetes as Container Orchestrators
Kubernetes, also known as K8s, makes it easier to deploy, scale, and operate containerized applications in production by providing tools for setting up containerized application clusters, managing application lifecycles, and executing workflows that span multiple containers. In other words, Kubernetes is the best tool for managing and operating large-scale, containerized applications. It’s a critical piece of the puzzle for DevOps teams who want to automate application deployment and management across distributed environments.
Kubernetes can be used to deploy and manage containerized applications on any cloud, including Azure. It also supports hybrid environments that are composed of on-premises and cloud-based resources.
Why use Kubernetes?
For software architects and engineers, K8s provide a number of benefits in managing software applications, including:
- A consistent and controlled environment for every application
Containerization makes it easy to deploy applications, but managing those containers becomes a challenge when the application scales up. Kubernetes helps to manage environments for containers so that every application is running in a consistent, controlled environment.
- Automated application deployment and lifecycle management
Kubernetes automates the deployment of new application versions and the reconfiguration of existing application instances. This results in a reduction in the time it takes to deploy new application versions and a reduction in the resources used when managing application instances.
- Increased application security
Kubernetes offers features that can help organizations to reduce the risk of security breaches. For example, Kubernetes supports the use of identity and access control systems, such as Microsoft Azure Active Directory, to manage application user access.
- Improved visibility into application performance
Kubernetes provides tools for monitoring application performance and identifying issues that may affect application performance. This enables organizations to identify and isolate issues quickly and take appropriate action.
Kubernetes and Docker
Kubernetes and Docker together provide a highly integrated platform for managing, deploying, and orchestrating containers at scale.
You can use Docker for building container images on a laptop, then run the containers in your Kubernetes cluster. The containers can then be deployed and started on any container-friendly platform, like Kubernetes, Docker Swarm, Mesos, or HashiCorp Nomad.
The difference between them is that Docker is for packaging containerized applications onto a single node, while Kubernetes is for running them on a cluster. Put in layman’s terms, Docker is about building single containers, whereas Kubernetes is about managing and orchestrating a vast amount of them.
For those who are already using Docker, Kubernetes leverages existing containers and workloads, all the while taking care of the difficult issues involved with scaling up. When demand spikes, Kubernetes provides Docker container orchestration, scheduling, and automatic deployments within its environments, to provide high availability.
Also, now that Docker has been deprecated by Kubernetes, any similar container runtime like Containerd or CRI-O could do the packaging for you.
Components of Kubernetes
To understand how K8s or Kubernetes work, let us look at their core components and their role in the functioning of a K8s system. The first step is to understand the foundations of the functionality and how Kubernetes clusters are set up.
A cluster is created when Kubernetes is deployed. Components, which are assemblages of services, make up a cluster. Kubernetes offers a lot of components you can use, but which one should you use? That depends on your overall needs. Here’s a list of some common components:
Kubernetes Engine: Kubernetes Engine is a managed cluster of Kubernetes components. It’s deployed in a cloud service and comes with multiple built-in templates, preconfigured clusters, an integrated scheduler, auditing, analytics, and reporting. Kubernetes Engine instances can be upgraded or downgraded. Kubernetes Engine is best used as a backend for on-premise clusters or building a production cluster with a minimum amount of configuration necessary.
Nodes: A Kubernetes cluster consists of a set of worker machines, called nodes, that run containerized applications. Every cluster has at least one worker node. All the other nodes expose a port on the network, which is called a Kube-public network. The Kube–public network is where you should select your cloud provider’s load balancer, so that your services, which are the applications, can be reached by the rest of your cluster.
Pod: The worker node(s) host the Pods that are the components of the application workload. The control plane manages the worker nodes and the Pods in the cluster. In production environments, the control plane usually runs across multiple computers and a cluster usually runs multiple nodes, providing fault tolerance and high availability. Prior to deployment, the control plane is configured by the project team, and a load balancer is bootstrapped that serves each Pod at a predefined IP address.
Kubernetes Dashboard: It is used to view and manage your on-premises Kubernetes cluster. The Kubernetes Dashboard allows you to create advanced, customized clusters and then manage all of the Kubernetes components using the tooling and workflows provided by Kubernetes.
Key features of Kubernetes and its benefits
Kubernetes offers a number of key features that make it easier to deploy, scale and operate containerized applications in production. These features include:
- Replication: Replication is a Kubernetes feature that allows developers to automatically create copies of containers across the entire application cluster. Replication is useful for a variety of use cases, including horizontal scaling, failover, and disaster recovery.
- Service abstraction: Kubernetes provides service abstraction which allows developers to create applications without having to worry about the underlying infrastructure. This abstraction enables developers to deploy applications that are portable across different environments, including public cloud platforms and on-premises environments.
- Service discovery: Kubernetes also offers service discovery functionality that allows developers to find each other’s services, even when those services are running in different containers across the application cluster.
Is Kubernetes right for your organization?
Now that you are all caught up on what Kubernetes (K8s) are and how they work… is it right for you? We will attempt to answer this question in the below section by listing out a few examples of what Kubernetes does best:
- In recent years, Kubernetes has become an industry standard to handle containers at scale because Kubernetes runs uniformly in all environments, on-premises as well as cloud-based ones such as AWS, Azure, and GCP. Kubernetes provides a more continuous, guided pathway for migrating applications from on-premises environments to cloud-based environments.
- Kubernetes users typically run more than one cluster for their production environments in the cloud. Kubernetes has also evolved to become a hybrid computing platform, which allows public cloud providers to run their managed services on clusters deployed in on-prem environments. In doing so, the Kubernetes platform makes many aspects of managing an application’s infrastructure focused on services straightforward and simple. In combination with the latest in CI/CD (Continuous Integration/Continuous Deployment) tools, Kubernetes is capable of scaling up such applications without requiring an extensive engineering project.
- Over the years, the big cloud providers, including AWS, GCP, and Microsoft Azure, have introduced tools and services to better enable getting started with Kubernetes and managing it. This finding, from the Sumo Logic continuous intelligence report, identified a very interesting trend in the uptake of K8s. Over 86% of organizations are using managed or native Kubernetes solutions. The Fortune 100 companies’ acceleration in using Kubernetes as the platform for their extensive hybrid cloud/multi-cloud infrastructure mirrors one of the macro trends: skyrocketing Kubernetes’s adoption in various industries.