Kubernetes, often abbreviated as K8s, is an open-source platform used to automate the deployment, scaling, and management of containerized applications. It was originally developed by Google and is now maintained by the Cloud Native Computing Foundation (CNCF).
Key Features of Kubernetes:
1. Automated Deployment: Kubernetes can automatically deploy containers across a cluster of machines, ensuring that the right resources are allocated.
2. Self-Healing: If a container fails, Kubernetes can restart or replace it automatically to maintain high availability.
3. Scaling: Kubernetes can automatically scale the number of running containers up or down based on demand, ensuring optimal resource usage.
4. Load Balancing: It distributes traffic evenly across containers to ensure high availability and performance.
5. Service Discovery: Kubernetes provides built-in service discovery, so applications don’t need to hard-code the location of services.
6. Storage Orchestration: Kubernetes can automatically manage storage for containers, connecting them to persistent storage if needed.
7. Rolling Updates and Rollbacks: Kubernetes allows for smooth updates of applications with minimal downtime. If something goes wrong, it can also roll back to a previous version.
Kubernetes Architecture:
• Nodes: Individual servers (physical or virtual) that run containerized applications.
• Pods: The smallest deployable units in Kubernetes, which can contain one or more containers.
• Cluster: A set of nodes managed by Kubernetes.
• Master Node: The central control point for the cluster, responsible for maintaining the desired state of the system (e.g., what apps should be running and where).
• Scheduler: Decides where to place new containers based on resource availability.
• Controller Manager: Ensures the system maintains the desired state, e.g., if a container fails, the Controller will bring up a new one.
• etcd: A key-value store that Kubernetes uses to store all its configuration data.
• kubelet: An agent running on each node that communicates with the master node and ensures containers are running correctly.
Kubernetes and Docker:
• Docker is used to create and manage individual containers.
• Kubernetes is used to orchestrate and manage groups of containers (including those created by Docker) across multiple nodes.
By combining containerization (e.g., Docker) and Kubernetes, organizations can achieve highly efficient, scalable, and resilient systems that support modern application architectures like microservices.