The Deployment adds or removes pods to maintain the desired application state, and tracks pod state to ensure optimal deployment. However, Kubernetes also supports a persistent storage mechanism called PersistentVolumes. Suppose you want to migrate to cloud technologies or enhance your current cloud infrastructure using Kubernetes. Migration to the cloud is not just complicated but can be expensive if done incorrectly.
Its main responsibility is to allocate non-overlapping pod subnets out to every node in the cluster. It exposes the Kubernetes API, which allows users and other components to interact with the cluster. The API server handles requests for creating, modifying, and deleting Kubernetes objects such as pods, services, and deployments.
It validates and processes these requests, enforces authentication and authorization policies, and stores the cluster state in etcd. Worker nodes in a cluster are machines or servers running applications, controlled by the Kubernetes master. In organizations, multiple numbers of containers run on multiple hosts at a time. So it becomes very hard to manage all the containers together, a simple solution to this would be Kubernetes. Kubernetes is an open-source platform for managing containerized workloads and services. Kubernetes take care of scaling and failover for our application running on the container.
Docker is the most popular tool for creating and running Linux® containers. Containers are lightweight, executable application components that combine application source code with all the operating system (OS) libraries and dependencies required to run the code in any environment. Multiple applications can now share the same underlying operating system.
It acts as a network proxy and service load balancer on its node, handling network routing for user datagram protocol (UDP) and transmission control protocol (TCP) traffic. Etcd is a distributed, fault-tolerant key-value store database that keeps configuration data and cluster status information. Although etcd may be set up independently, it often serves as a part of the Kubernetes control plane. Gartner’s Container Best Practices suggest a platform strategy that considers security, governance, monitoring, storage, networking, container lifecycle management and orchestration like Kubernetes. VMware is addressing cloud chaos with our portfolio of multi-cloud services, VMware Cross-Cloud services, which enable you to build, run, manage, secure, and access applications consistently across cloud environments.
Additionally, you can choose to run Kubernetes on your own or work with a vendor who can provide a supported version. Beyond just managing the containers that run an application, Kubernetes can also manage the application data attached to a cluster. Kubernetes allows users to request storage resources without having to know the details of the underlying storage infrastructure. Persistent volumes are specific to a cluster, rather than a pod, and thus can outlive the life of a pod. GitOps is a modern software development and operations approach gaining industry-wide traction with tools like ArgoCD and Flux.
Here, a third-party server provider will lend a space in their servers to an organization. Even though it is an excellent way for many, the lock-in by such providers may be a deal-breaker for some. On the other hand, Kubernetes architecture lets the organization build a serverless platform with the existing infrastructure. Sometimes replicating a controller can kill the existing pod and commence a new set. Moreover, Kubernetes does not claim that a physical pod will remain alive in any such stance. Service depicts a set of pods that lets pods send a necessary request to the service.
It has intelligent logic to forward the request to the right pod in the worker node. Kubernetes Cluster mainly consists of Worker Machines called Nodes and a Control Plane. The Kubectl CLI communicates with the Control Plane and Control Plane manages the Worker Nodes. When run in high-availability mode, many databases come with the notion of a primary instance and secondary instances. Other applications like Apache Kafka distribute the data amongst their brokers; hence, one broker is not the same as another.
The master node and other components interact with etcd to read and write the desired state of the cluster. Etcd ensures data consistency and provides a reliable source of truth for the cluster. Kubernetes is a software framework for building and operating containerized applications. Kubernetes is designed to be easy to use and to give developers the power to control and scale their applications. Kubernetes is an open source project that is being developed by Google. Some companies merge Kubernetes with their existing systems for better performance.
Kubernetes is growing swiftly in the IT infrastructure within the organizations, but why is it happening? To understand that, it is essential to know the traditional method of running applications. In the traditional methods, its impossible to define resource boundaries for any application running on a physical server. The situation worsened when the organization needed to run more than one application on a physical server. There are various controllers in a Kubernetes ecosystem that drive the states of endpoints (pods and services), tokens and service accounts (namespaces), nodes, and replication (autoscaling). The controller manager—sometimes called cloud controller manager or simply controller—is a daemon which runs the Kubernetes cluster using several controller functions.
Each compute node has a network proxy known as a kube-proxy, which aids Kubernetes networking services. To manage network connections inside and outside the cluster, the kube-proxy either forwards traffic or depends on the operating system’s packet filtering layer. Kubernetes is a portable, extensible, open source platform for managing containerized
workloads and services, that facilitates both declarative configuration and automation. Etcd primarily stores the kubernetes objects, cluster information, node information, and configuration data of the cluster, such as the desired state of the applications running on the cluster. Cloud controller integration allows Kubernetes cluster to provision cloud resources like instances (for nodes), Load Balancers (for services), and Storage Volumes (for persistent volumes).
Thus, Google’s third-generation container management system, Kubernetes, was born. Red Hat OpenShift offers these components with Kubernetes at their core because—by itself— Kubernetes is not enough. The kubernetes based assurance control plane manages the cluster nodes responsible for running the containers. Every node runs a container runtime engine and acts as an agent to communicate with the primary Kubernetes controller.
In addition, other components for service discovery, monitoring, and logging are also done by these nodes. Being directly related to the control plane, knowing about the components of Kubernetes architecture is crucial. A modern, distributed application services platform is the only option for delivering an ingress gateway for applications based on Kubernetes microservices architecture. For web-scale, cloud-native applications deployed using container technology as microservices, traditional appliance-based ADC solutions are not up to the task of managing Kubernetes container clusters. Each can have hundreds of pods with thousands of containers, mandating policy driven deployments, full automation, and elastic container services. Managed by the control plane, cluster nodes are machines that run containers.
Configuration data and information about the state of the cluster lives in etcd, a key-value store database. Fault-tolerant and distributed, etcd is designed to be the ultimate source of truth about your cluster. Please register here to join a live demo of our new Kubernetes experience on December 14, 2023, delivered by our engineering and product management team. The rollout of all capabilities will start in February 2024 on all Dynatrace SaaS environments. Dynatrace supports DevOps teams in their independence from platform engineers by enabling observability features for their applications using a simple toggle in the Dynatrace web UI. This way, DevOps teams can independently decide which namespaces they want to enable APM for, all the way down to self-service log collection.