Kubernetes

What is Kubernetes?

Kubernetes is a container orchestration tool—an open-source, extensible platform for deploying, scaling and managing the complete life cycle of containerized applications across a cluster of machines. Kubernetes is Greek for helmsman, and true to its name, it allows you to coordinate a fleet of containerized applications anywhere you want to run them: on-premises, in the cloud, or both.

Where did Kubernetes originate?

Docker has taken the world by storm, with container orchestration solutions like Kubernetes helping enterprises scale, monitor, and automate applications in containers. Kubernetes is managed by the Cloud Native Computing Foundation under the auspices of the Linux Foundation. It’s supported by thousands of contributors, including top corporations such as Red Hat and IBM, as well as certified partners—experienced service providers, training providers, certified distributors, hosted platforms, and installers.

Kubernetes originate

What is Kubernetes used for?

Kubernetes is used to manage microservices architectures and is often deployed in most cloud environments.

Amazon Web Services, Google Cloud Platform, and Microsoft Azure all support Kubernetes, enabling IT to move applications to the cloud more easily. Kubernetes offers many benefits for developers, with capabilities such as service discovery and load balancing, automatic deployment and rollback, and auto-scaling based on traffic and server load. Kubernetes is crucial because:

  • As the Containerization ecosystem is maturing, Kubernetes is the default for the cloud
  • Platform-as-a-Service (PaaS) offerings like Red Hat’s OpenShift, based around Docker containers, enable developers to share source code and extensions
  • When developers contribute code to the open source Kubernetes project on GitHub, they are contributing their expertise and making the platform even more robust
  • Containers are a must-have for DevOps; they provide developers a way to quickly build, deploy, run, and scale their applications. They enable long-running services to always be available and help to eliminate the need to worry about infrastructure issues and infrastructure updates.

What is a Kubernetes cluster?

A Kubernetes cluster is the physical platform that underpins Kubernetes architecture. If you think of it, it’s a way to bring together individual physical and virtual machines on a network and can be viewed as a series of layers, each of which abstracts the layer beneath it. Whether you use Kubernetes, the control plane of the cloud, the building blocks of which are the nodes, pods, and a control plane.

In the control plane, we run on a server, or, for purposes of fault tolerance and high availability, in a group of servers. Also known as the master node, the control plane runs the Kubernetes API and manages the worker nodes and pods in the cluster.

Kubernetes cluster

K8s is a tool that ensures that Kubernetes interacts well with applications and maintains the cluster’s desired state, such as which applications are running and which container images they use. The four major components of the control plane are

  • API server: The front-end of the cluster controls the overall cluster health by directing all of the messages between components. Local computers interact with the Kubernetes cluster using a client called kubectl.
  • Scheduler: This component assigns newly formed pods to a node and assigns workloads to specific nodes in the cluster.
  • Controller-manager: This ensures that the cluster is functioning correctly and tracks the available capacity of each controller and other services in the cluster. 
  • etcd: The distributed key-value store that maintains details about how Kubernetes needs to be configured.

Worker nodes perform tasks requested by the control plane. They include the following components that run on every node to maintain running pods:

  • Kubelet: This software agent executes orders from the master node and ensures the containers are running and healthy.
  • Kube-proxy: This service maintains network rules on nodes.
  • Container runtime: This software, such as Docker, is responsible for starting and running containers.

Kubelets are the group of one or more containers and the smallest units in Kubernetes architecture. They have the same computing resources and the same network. Each pod represents a single instance of an application, and each is assigned a unique IP address. This enables applications to use ports. The pods are created and destroyed on the nodes as needed to keep the system stable.

What is a service in Kubernetes?

 Kubernetes, a container orchestration platform, enables developers to run any containerized application across many servers or nodes, regardless of language or framework. The service maintains a stable IP address and a single DNS name for a set of pods so that as they are created and destroyed, the other pods can connect using the same IP address. The Kubernetes documentation says that the pods that make up the backend of an application don’t need to change, but the front end does.

What are Kubernetes networking and load balancing?

Networking is central to the distributed systems that run a cluster. Kubernetes networking uses the idea that every container in a pod has a unique IP address that is shared by all the containers in the pod and is routable from all other pods regardless of what node they are on. To ensure that a container is always running and able to respond to service requests, you must designate a shared network namespace for the container.

Kubernetes networking and load balancing

If each pod contains its own IP address, then there is only one port per pod. You can run multiple applications in a pod without affecting traffic between pods. The POD-per-Pod model is a new and promising approach that empowers container developers to run containerized apps in any size that fits their needs. To provide services that require Internet connectivity, Cloud platforms like Amazon EC2 use IP addresses to control access to these services. There is a Kubernetes feature called kube-proxy, which implements the iptables feature of using either random or round-robin IP management to distribute network traffic among pods on an IP list.

What is a Kubernetes ingress controller?

As a result, kube-proxy does not provide advanced features, including Layer 7 load balancing and observability, making it unsuitable for Ingress as a load balancer. An Ingress API object that enables you to set up traffic routing rules for managing external access to the Kubernetes cluster. Ingress is just the first step. However, it specifies the traffic rules and the destination but requires an additional component, an ingress controller, to actually grant access to external services.

A Kubernetes ingress controller provides routing, filtering, and other services that ensure that incoming requests reach the appropriate applications. There is a wide range of open-source ingress controllers available, and all major cloud providers support ingress controllers that are compatible with their load balancers and integrate natively with other cloud services. You can use Kubernetes to run many ingress controllers within your cluster. They can be used to address each request and select the one that matches the best conditions at that point in time.

AppViewX solutions for Kubernetes

Microservice deployment in a Kubernetes-enabled environment is critical for any organization that’s embarking on its journey to microservices. With AppViewX ADC+, IT and DevOps managers can deploy applications in Kubernetes without worrying about the complexities of running a highly scaled system themselves. With one package containing all these benefits that come from isolation, efficiency, and safety.

  • Cloud agnostic managed Kubernetes support (EKS, AKS, GKE)
  • Cloud agnostic native deployment support (AWS, Azure, GCP)
  • Eliminate operational complexity with a user-friendly platform
  • Enterprise-ready architecture and standardized deployment

Appviewx product that automates the deployment of applications using Kubernetes: ADC+