JN0-214 Exam Dumps : Cloud Associate (JNCIA-Cloud)

The YAML file provided in the exhibit defines a KubernetesServiceobject of typeNodePort. Let’s break down the key components of the configuration and analyze how external users access the WEB application:

Key Fields in the YAML File:

type: NodePort:

This specifies that the service is exposed on a static port on each node in the cluster. External users can access the service using the node's IP address and the assignednodePort.

port: 8080:

This is the port on which the service is exposed internally within the Kubernetes cluster. Other services or pods within the cluster can communicate with this service using port8080.

targetPort: 5000:

This is the port on which the actual application (WEB application) is running inside the pod. The service forwards traffic fromport: 8080totargetPort: 5000.

nodePort: 31000:

This is the port on the node (host machine) where the service is exposed externally. External users will use this port to access the WEB application.

How External Users Access the WEB Application:

External users access the WEB application using the node's IP address and thenodePortvalue (31000).

The Kubernetes service listens on this port and forwards incoming traffic to the appropriate pods running the WEB application.

Why Not Other Options?

A. 80:Port80is commonly used for HTTP traffic, but it is not specified in the YAML file. The service does not expose port80externally.

B. 8080:Port8080is the internal port used within the Kubernetes cluster. It is not the port exposed to external users.

D. 5000:Port5000is the target port where the application runs inside the pod. It is not directly accessible to external users.

Why 31000?

NodePort Service Type:TheNodePortservice type exposes the application on a high-numbered port (default range: 30000–32767) on each node in the cluster.

External Accessibility:External users must use thenodePortvalue (31000) along with the node's IP address to access the WEB application.

JNCIA Cloud References:

The JNCIA-Cloud certification covers Kubernetes networking concepts, including service types likeClusterIP,NodePort, andLoadBalancer. Understanding howNodePortservices work is essential for exposing applications to external users in Kubernetes environments.

For example, Juniper Contrail integrates with Kubernetes to provide advanced networking features, such as load balancing and network segmentation, for services like the one described in the exhibit.

OpenStack provides various services to manage cloud infrastructure resources, including compute nodes and virtual machines (VMs). Let’s analyze each option:

A. Keystone

Incorrect: Keystoneis the OpenStack identity service responsible for authentication and authorization. It does not display server details of compute nodes.

B. Neutron

Incorrect: Neutronis the OpenStack networking service that manages virtual networks, routers, and IP addresses. It is unrelated to displaying server details of compute nodes.

C. Cinder

Incorrect: Cinderis the OpenStack block storage service that provides persistent storage volumes for VMs. It does not display server details of compute nodes.

D. Nova

Correct: Novais the OpenStack compute service responsible for managing the lifecycle of virtual machines, including provisioning, scheduling, and monitoring. It also provides detailed information about compute nodes and VMs, such as CPU, memory, and disk usage.

Why Nova?

Compute Node Management:Nova manages compute nodes and provides APIs to retrieve server details, including resource utilization and VM status.

Integration with CLI/REST APIs:Commands likeopenstack server showornova hypervisor-showcan be used to display compute node and VM details.

JNCIA Cloud References:

The JNCIA-Cloud certification covers OpenStack services, including Nova, as part of its cloud infrastructure curriculum. Understanding Nova’s role in managing compute resources is essential for operating OpenStack environments.

For example, Juniper Contrail integrates with OpenStack Nova to provide advanced networking and security features for compute nodes and VMs.

Docker provides various commands to manage and interact with Docker objects such as containers, images, networks, and volumes. To obtainlow-level informationabout these objects, thedocker inspectcommand is used. Let’s analyze each option:

A. docker info <OBJECT_NAME>

Incorrect:Thedocker infocommand provides high-level information about the Docker daemon itself, such as the number of containers, images, and system-wide configurations. It does not provide detailed information about specific Docker objects.

B. docker inspect <OBJECT_NAME>

Correct:Thedocker inspectcommand retrieves low-level metadata and configuration details about Docker objects (e.g., containers, images, networks, volumes). This includes information such as IP addresses, mount points, environment variables, and network settings. It outputs the data in JSON format for easy parsing and analysis.

C. docker container <OBJECT_NAME>

Incorrect:Thedocker containercommand is a parent command for managing containers (e.g.,docker container ls,docker container start). It does not directly provide low-level information about a specific container.

D. docker system <OBJECT_NAME>

Incorrect:Thedocker systemcommand is used for system-wide operations, such as pruning unused resources (docker system prune) or viewing disk usage (docker system df). It does not provide low-level details about specific Docker objects.

Why docker inspect?

Detailed Metadata: docker inspectis specifically designed to retrieve comprehensive, low-level information about Docker objects.

Versatility:It works with multiple object types, including containers, images, networks, and volumes.

JNCIA Cloud References:

The JNCIA-Cloud certification covers Docker as part of its containerization curriculum. Understanding how to use Docker commands likedocker inspectis essential for managing and troubleshooting containerized applications in cloud environments.

For example, Juniper Contrail integrates with container orchestration platforms like Kubernetes, which rely on Docker for container management. Proficiency with Docker commands ensures effective operation and debugging of containerized workloads.