Kubernetes Components – What are they?
Kubernetes is a popular open-source container orchestration platform that automates the deployment, scaling, and management of containerized applications. It consists of several components that work together to provide a robust and scalable container orchestration solution.
Key Kubernetes Components
These components work together to provide a robust and scalable container orchestration solution in Kubernetes. The master components manage the overall state and configuration, while the node components run and maintain containers on individual cluster nodes. Various controllers and services help automate and maintain the desired state of applications within the cluster.
Here are some key Kubernetes components:
Master Components
- kube-apiserver: this component exposes the Kubernetes API and serves as the entry point for all administrative tasks.
- etcd: a distributed key-value store used to store the cluster’s configuration data, ensuring consistency and fault tolerance.
- kube-scheduler: responsible for scheduling containers to run on individual nodes based on resource requirements and other constraints.
- kube-controller-manager: manages controller processes that regulate the state of the cluster, such as node and replication controllers.
Node Components
- kubelet: an agent that runs on each node in the cluster and ensures that containers are running in a Pod.
- kube-proxy: maintains network rules on nodes, enabling communication between Pods and external traffic.
Add-ons
- DNS (kube-dns/coredns): provides DNS-based service discovery for services within the cluster.
- Dashboard: a web-based user interface for managing and monitoring the Kubernetes cluster.
- Ingress Controller: manages external access to services within the cluster, typically by exposing HTTP and HTTPS routes.
- Container Network Interface (CNI): defines how networking is established between Pods.
Pods
The smallest and simplest deployable object in the Kubernetes object model, representing one or more containers deployed together on a node.
Controllers
- Replication Controller/ReplicaSet: ensures that a specified number of replicas for a Pod are running at all times.
- Deployment: provides declarative updates to applications, allowing them to be scaled up or down and updated with ease.
- StatefulSet: manages the deployment and scaling of a set of Pods with unique, stable network identifiers.
Storage
Persistent Volumes (PV) and Persistent Volume Claims (PVC) provide a way for containers to access persistent storage.
These components work together to create a scalable and resilient container orchestration platform. Kubernetes allows users to deploy and manage containerized applications efficiently, abstracting away the underlying infrastructure complexities.
