What is Kubernetes?
Kubernetes is the most popular orchestrator for deploying and scaling containerised systems. You can use Kubernetes to reliably build and distribute your applications that use cloud solutions . In this article, you will learn what Kubernetes can do and how to start running your own containerised solutions.
What is Kubernetes?
Kubernetes is an open-source system that automates container deployment tasks . It was originally developed at Google, but is now maintained as part of the Cloud Native Computing Foundation (CNCF).
Kubernetes has gained prominence because it solves many of the problems associated with using containers in production . It facilitates the launch of unlimited container replicas, their distribution across multiple physical hosts, and the establishment of a network to access your services.
Most developers start by using containers with Docker . Although it is a complete tool, it is a relatively low-level tool that relies on CLI commands that interact with only one container at a time.
Kubernetes provides much higher-level abstractions that allow you to define applications and their infrastructure using declarative models on which you can collaborate.
How does Kubernetes work?
Kubernetes has a reputation for being complex , as it has several moving elements . Understanding the basics of how they fit together will help you understand how Kubernetes works.
A Kubernetes environment is called a cluster . It includes one or more nodes . A node is simply a machine that will run your containers . It can be a physical hardware or a VM (virtual machine or Virtual Machine).
In addition to the nodes, the cluster also has a control plane . The control plane coordinates all cluster operations. It allows you to schedule new containers on the available nodes and to provide the Kubernetes service you are interacting with.
It is possible to run a cluster with multiple control plane instances to create a highly available configuration with more resilience.
Here are the main components of Kubernetes:
Kube-apiserver
This is the part of the control plane that runs the API server. This is the only way to interact with a running Kubernetes cluster. You can send commands to the API server using the Kubectl CLI or an HTTP client.
Kube-controller-manager
The Controller Manager starts and runs the built-in Kubernetes controllers. A controller is essentially an event loop that applies actions after changes in your cluster. They create, scale, and drop objects in response to events such as an API request or a load increase.
Kube-scheduler
The scheduler assigns new pods (containers) to the nodes in your cluster. It determines which nodes can meet the requirements of the pod, then selects the most optimal location to maximize performance and reliability.
Kubelet
Kubelet is a worker process that runs on each of your nodes. It maintains communication with the Kubernetes control plane to receive its instructions. Kubelet is responsible for extracting container images and starting containers in response to scheduling requests.
kube-proxy
The proxy is another component present on the individual nodes. It configures the host network system so that traffic can reach your cluster’s services.
Kubectl is usually the last element of a functional Kubernetes environment . You will need this CLI to interact with your cluster and its objects. Once your cluster is configured, you can also install the official dashboard or a third-party solution to control Kubernetes from a graphical interface.
The advantages of Kubernetes
Kubernetes and containerization offer many advantages for businesses and providers looking to build and maintain scalable, resilient, and portable applications. Here are some of the key benefits of Kubernetes:
Containerisation
Kubernetes uses containerization technology, such as Docker, to encapsulate applications and their dependencies in lightweight, isolated units called containers. Containers offer several advantages, including better resource utilization, easy packaging of applications, and consistent behavior across different environments.
Scalability
Kubernetes enables effortless application scalability. It allows you to scale your microservices applications horizontally by adding or removing instances, called pods, depending on the workload. This helps you ensure your application can handle increased traffic or accommodate larger resource requirements. This improves performance and responsiveness, and is especially necessary when migrating workloads to DevOps.
High availability
Kubernetes supports high availability by providing automated failover and load balancing mechanisms. It can automatically restart failed containers, replace unhealthy instances, and distribute traffic between healthy instances. This ensures that your application remains available even in the event of infrastructure or container failure. This helps to reduce downtime and improve reliability.
Resource efficiency:
With advanced planning capabilities, Kubernetes optimizes resource allocation and utilization. It intelligently distributes containers across nodes based on resource availability and workload requirements. This helps maximize the use of IT resources, minimize waste, and reduce costs.
Self-healing:
Kubernetes has self-healing capabilities, which means it automatically detects and processes problems within the application environment. If a container or node goes down, Kubernetes can reschedule containers on healthy nodes. It can also replace failed instances and even perform automated updates without interrupting the overall availability of the application.
Portability:
Kubernetes offers portability, making it easy to move applications between different environments, such as on-premises datacentres, public clouds, or hybrid configurations. Its container-centric approach ensures that applications and their dependencies are aggregated. This reduces the risk of compatibility issues and enables seamless deployment across various infrastructure platforms.
DevOps facilitation:
Kubernetes enables collaboration between development and operations teams by providing a unified platform for application deployment and management. It allows developers to define application configurations as code using Kubernetes manifests, enabling repeatable, version-controlled deployments.
Operations teams can leverage Kubernetes to automate deployment workflows, monitor application health, and implement continuous integration and delivery (CI/CD) pipelines.
Types of applications that work with Kubernetes
Kubernetes can be used to deploy a wide range of applications, including web applications, microservices, databases, and more. Let's explore the different types of applications that can be deployed on Kubernetes.
Web applications
Web applications are the most common type of application deployed on Kubernetes. They are usually made up of several containers , including a web server , an application server and a database . Kubernetes can easily manage these containers and ensure that they work properly. Kubernetes also allows you to easily scale your web applications, both horizontally and vertically, according to demand.
Web applications are also very well-suited due to their ability to be deployed quickly and on a continuous basis . While applications with long running states can be hosted on Kubernetes, web applications usually have a very short lifecycle for processing their requests . This means they can quickly be upgraded to a new version without affecting end users.
Microservices
Kubernetes is an excellent platform for deploying microservices , as it allows you to deploy each microservice as a separate container . This makes it easy to scale individual microservices independently and also allows you to update and deploy new versions of a microservice without affecting the rest of the application.
Databases
Databases are essential components of many applications, and Kubernetes can also be used to deploy and manage them. There are different types of databases that can be deployed on Kubernetes, including SQL, NoSQL, and key-value databases (also known as the KVS or Key-Value Store ).
Kubernetes provides features such as stateful sets and persistent volumes that allow you to deploy databases and ensure that their data persists even if containers are restarted or moved to another node.
When you are in the cloud, you can use EC2 (or equivalent solution) to create fast, persistent storage directly on your containers . Moving this storage to a new container is also trivial. Your on-premises solutions are much more varied and complex to manage. Be careful when it comes to this, as storage issues can quickly put an end to your Kubernetes database adventure.
BigData
Kubernetes can also be used to deploy big data applications such as Apache Spark and Hadoop. These applications require a large number of resources to operate, and Kubernetes can manage these resources efficiently. Kubernetes can also be used to orchestrate the deployment of different big data components , such as data ingestion, processing and storage.
Machine learning
Kubernetes provides features such as resource quotas and resource limits that can be used to ensure machine learning models work properly.
IoT
The Internet of Things (IoT) is a growing field of connecting physical devices to the internet. Kubernetes can be used to deploy and manage IoT applications, including edge computing applications.
Container solutions
The container solutions are well-suited to Kubernetes, as it offers a powerful and flexible orchestration to manage large-scale container deployments. With Kubernetes, you can easily deploy and manage container solutions in cloud environments or on-premises environments.
OVHcloud and Kubernetes
Free Managed Kubernetes® service to orchestrate your containers
Kubernetes® is one of the most widely-used container orchestration tools on the market. It is used by companies of all sizes. It can be used to deploy applications, scale them up and make them more resilient – even in hybrid or multi-cloud infrastructures.
Service Managed Kubernetes® is powered by OVHcloud Public Cloud instances. With OVHcloud Load Balancers and additional disks integrated into it, you can host any kind of work load on it with total reversibility.
FAQs
What are the differences between Kubernetes and Docker?
Docker packages and deploys applications in lightweight containers, while Kubernetes automates the deployment and management of these containers at scale. Together, they form a powerful ecosystem for developing and managing modern applications.
Is Kubernetes a DevOps tool?
Kubernetes, well used in DevOps practices, automates the deployment, management and scaling of applications, facilitating collaboration between development and operations teams for agile and scalable deployments.