Which two statements are correct about Kubernetes resources?

Kubernetes resources are the building blocks of Kubernetes clusters, enabling the deployment and management of applications. Let’s analyze each statement:

A. A ClusterIP type service can only be accessed within a Kubernetes cluster.

Correct:

AClusterIPservice is the default type of Kubernetes service. It exposes the service internally within the cluster, assigning it a virtual IP address that is accessible only to other pods or services within the same cluster. External access is not possible with this service type.

B. A daemonSet ensures that a replica of a pod is running on all nodes.

Correct:

AdaemonSetensures that a copy of a specific pod is running on every node in the cluster (or a subset of nodes if specified). This is commonly used for system-level tasks like logging agents or monitoring tools that need to run on all nodes.

C. A deploymentConfig is a Kubernetes resource.

Incorrect:

deploymentConfigis a concept specific to OpenShift, not standard Kubernetes. In Kubernetes, the equivalent resource is called aDeployment, which manages the desired state of pods and ReplicaSets.

D. NodePort service exposes the service externally by using a cloud provider load balancer.

Incorrect:

ANodePortservice exposes the service on a static port on each node in the cluster, allowing external access via the node's IP address and the assigned port. However, it does not use a cloud provider load balancer. TheLoadBalancerservice type is the one that leverages cloud provider load balancers for external access.

Why These Statements?

ClusterIP:Ensures internal-only communication, making it suitable for backend services that do not need external exposure.

DaemonSet:Guarantees that a specific pod runs on all nodes, ensuring consistent functionality across the cluster.

JNCIA Cloud References:

The JNCIA-Cloud certification covers Kubernetes resources and their functionalities, including services, DaemonSets, and Deployments. Understanding these concepts is essential for managing Kubernetes clusters effectively.

For example, Juniper Contrail integrates with Kubernetes to provide advanced networking features for services and DaemonSets, ensuring seamless operation of distributed applications.