Kubernetes Entities

1. Cluster-Level Entities

• Node: A physical or virtual machine in the cluster.
• Namespace: A logical grouping of resources within a cluster.
• Context: A combination of cluster, namespace, and user configuration.

2. Workload Management

• Pod: The smallest deployable unit, running one or more containers.
• Deployment: Manages the deployment and scaling of Pods.
• ReplicaSet: Ensures a specified number of pod replicas are running.
• DaemonSet: Ensures that a copy of a pod runs on all nodes.
• StatefulSet: Manages stateful applications with stable network IDs.
• Job: Runs a batch task until completion.
• CronJob: Runs scheduled jobs at specified times.

3. Networking and Traffic Management

• Service: Exposes a set of Pods as a network service.
• Ingress: Manages external access to Services inside the cluster.
• IngressClass: Defines the type of Ingress controller used in the cluster.
• IngressRoute: A CRD (Custom Resource Definition) for managing Ingress traffic in some controllers.
• Endpoint: Represents the IPs where a Service is reachable.

4. Storage and Configuration

• ConfigMap: Stores non-sensitive configuration data as key-value pairs.
• Secret: Stores sensitive information like passwords or API keys.
• PersistentVolume (PV): A piece of storage provisioned by an administrator.
• PersistentVolumeClaim (PVC): A request for storage by a user.
• StorageClass: Defines the storage type and parameters for dynamic volume provisioning.

5. Security and Identity Management

• ServiceAccount: Provides an identity for processes running in a Pod.
• Role & RoleBinding: Defines permissions within a specific namespace.
• ClusterRole & ClusterRoleBinding: Defines permissions across all namespaces.
• NetworkPolicy: Controls communication between pods based on rules.
• ClusterIssuer: Manages certificate issuance at the cluster level.
• CertificateRequest: Requests a certificate from a ClusterIssuer.

6. Resource Management

• LimitRange: Defines constraints on resource usage within a namespace.
• ResourceQuota: Limits resource consumption in a namespace.

7. Logging and Monitoring

• Event: Provides information on state changes and errors in the cluster.
• MetricServer: Collects resource usage data for Pods and Nodes.

8. Custom Resource Definitions (CRDs)

• CustomResourceDefinition (CRD): Allows users to define and manage their own Kubernetes objects.

These entities form the core components of Kubernetes, allowing for scalable, secure, and efficient application deployment and management.