To understand what Kubernetes (or K8s) is, let’s get back to the basics and take a look at what are software containers and why they are so useful.
Every innovation in the technical sphere is meant to overcome the limitations posed by the previous concept. Something similar is in the case of containers as well. They were introduced to the software development world to deal with the challenges of physical servers and virtualization.
For a long time, organizations have been running their applications on physical servers. With this traditional mode of deployment, multiple applications would run on a single server. In such a scenario, one application might take up all the resources, affecting the performance of other applications. To overcome this problem of resource allocation, the solution would be to run the applications on different servers. But, this would result in the under-utilization of resources for an application that requires minimal resources. Also, it becomes a costly affair to maintain an individual server for every application.
As a solution to this, virtualization was introduced that allowed running multiple virtual machines on resources of a single physical server. And in doing so, the hypervisor has a key role to play. A hypervisor is a software that divides the power of a physical server to multiple users or workloads. It creates a line of demarcation between multiple virtual server instances to ensure that data on a virtual machine is not visible to another user (despite all of them using the same computing machine).
When virtualization offered so many benefits, then why containers? Virtual machines work well for monolithic software architecture. Modern applications run on different platforms (mobile, TV, laptops, etc.), and to reduce the complexity of these solutions, developers prefer to group the application into loosely coupled light-weight services (microservice software architecture).
When multiple application components run within a single VM, there are chances of components/libraries conflicting with each other. This can be related to problems that IT teams generally encounter when they run multiple applications on a single physical server.
In addition to this, virtualization imposes performance challenges. Virtual machines that run their own execution environment and a copy of OS use entire hardware resources to run the applications. This is where containers come into the picture.
Contrary to virtual machines that perform application isolation at the hardware level, containers do this job at the operating system level. A single OS instance can support multiple containers, running in a separate execution environment. When multiple components run on a single OS, it helps to reduce the overhead and also free up processing power for the application components.
Containers are lightweight because they share the kernel of the OS. They have their own memory, CPU share, filesystem, process space, etc. Because they are decoupled from the underlying infrastructure, they are portable across OS distributions and clouds.
Now that we have a fair understanding of software containers and why do they exist, we can move ahead and discuss the importance of Kubernetes.
What is Kubernetes (K8s)?
Kubernetes is a container orchestration tool.
Container orchestration is the automation of operational efforts that are required to run containerized services and workloads. This may include (but is not limited to) provisioning, deployment, networking, load balancing, scaling up & down, etc.
Just think of a simple scenario where a container goes down and another container needs to start. If this job has to be automated, then a platform like Kubernetes is the solution.
Kubernetes is an open-source, portable platform for orchestrating containers. With a platform like Kubernetes, the operations team has the following advantages:
- Automate Load Balancing: If traffic to a container is high, Kubernetes distributes the network traffic to ensure that the deployment is stable. K8s is helpful in balancing the container load.
- Container Management: Kubernetes monitor all the pods and take relevant actions accordingly For example, for containers that fail to work, Kubernetes restarts or replaces them.
- Automatic Scheduling: K8s optimize the application performance by distributing pods in the most appropriate node.
- Automate Rollouts & Rollbacks: Kubernetes automates the process of creating or removing containers. It helps to manage the rollouts and rollbacks so that the applications are easily containerized for deployment.
Kubernetes was open-sourced by Google in 2014 after utilizing it for almost a decade to run production workloads. In a worldwide survey by Statista that took place in March 2021 (with 4,291 respondents), 46% confirmed that they use Kubernetes to dynamically scale applications and containerize them.
By 2022, 75% of organizations would be running containerized applications in production, according to Gartner. Some of the powerful reasons behind its adoption include Kubernetes being a platform that minifies cloud computing costs whilst simplifying the running of complex, scalable applications.
Along with a huge market adoption, Kubernetes has got several competitors. Azure Container Instances (ACI), Google Cloud Run, Openshift Container Platform, Docker Swarm, Rancher, Nomad are to name a few.
Kubernetes is a set of independent, composable control processes. These processes help in driving an application from the current state to the provided desired state.
Platforms like Kubernetes are also driving us towards the containerization era that’s enabling the software development ecosystem to overcome the limitations of virtualization. What are your thoughts on the benefits of container orchestration platforms like Kubernetes? Share with us in the comments below.