What is Kubernetes ?
Kubernetes is an open-source system that automates the deployment, scaling, and management of containerized applications. It’s essentially a platform that orchestrates clusters of virtual machines, scheduling containers to run on them based on resource availability. Kubernetes also automates operational tasks like rolling out changes, scaling up/down, and monitoring applications.
Here’s a more detailed explanation:
What is Kubernetes?
Kubernetes is an open-source system that automates the deployment, scaling, and management of containerized applications. It’s essentially a platform that orchestrates clusters of virtual machines, scheduling containers to run on them based on resource availability. Kubernetes also automates operational tasks like rolling out changes, scaling up/down, and monitoring applications.
Components of Kubernetes
Containers: Kubernetes works with containerized applications. Containers package an application and its dependencies into a lightweight, portable environment, making it easier to deploy and manage across different systems. Orchestration: Kubernetes orchestrates containers by managing their lifecycle, including deployment, scaling, and scaling back down. It also handles tasks like load balancing, automatic restarts, and fault tolerance. Clusters: Kubernetes clusters consist of a group of computing nodes (or worker machines) that run containerized applications.
Control Plane: A control plane manages the cluster, including tasks like scheduling containers, maintaining resource allocation, and monitoring the health of the cluster. Pods: Containers within a Kubernetes cluster are grouped into pods, which are the basic unit of deployment. Automated Tasks: Kubernetes automates many of the manual tasks involved in managing containerized applications, making it easier to deploy, scale, and manage applications at scale.
Benefits: Using Kubernetes can lead to more resilient, scalable, and easily manageable applications, especially in complex, distributed environments.
Kubernetes Cluster Architecture
Component of a Cluster
- Control Plane:
- API Server: Central management point
- etcd: Cluster state database
- Controller Manager: Maintains desired state
- Scheduler: Places pods on nodes
- Worker Nodes:
- Kubelet: Node agent
- Container Runtime: Runs containers
- Kube Proxy: Networking rules
- Pods: Groups of containers
- External Access:
- kubectl CLI: Command-line interface
- Load Balancer: External traffic distribution
- Ingress: HTTP/HTTPS routing
- Storage:
- Persistent Volumes: Durable storage
- Networking:
- CNI: Pod networking
- Network Policies: Traffic rules
The arrows show the communication flow between components. For example:
- All components communicate through the API Server
- Kubelets on worker nodes report to API Server
- Pods can access Persistent Volumes
- Network policies control pod communication