KCNA EXAM 1

Explanation:

Here’s a breakdown of what each option does:

• A. kube_pod_container_resource_requests_cpu_cores{pod=""}
  → Shows CPU resource requests configured for a pod. Doesn’t show actual usage or request volume.

• B. kube_pod_container_status_restart_count{pod=""}
  → Shows how many times a pod/container has restarted. Not relevant for identifying a traffic spike to a specific endpoint.

• C. kube_http_server_requests_seconds_bucket{job="", method="GET", uri="/specific_endpoint"}
  ✅ This is a histogram metric that tracks the number of HTTP requests to a specific URI (/specific_endpoint). This is directly useful for identifying heavily accessed endpoints.

• D. kube_deployment_status_replicas{deployment=""}
  → Shows the number of replicas in a deployment. Useful for scaling insights, but not for identifying request spikes to specific endpoints.

• E. kube_pod_status_phase{pod=""}
  → Shows whether a pod is Running, Pending, etc. Not useful for endpoint-level traffic analysis.

Explanation:

In a cloud-native migration, the Cloud Architect is primarily responsible for:

• Designing the overall Kubernetes infrastructure.

• Defining resource allocation strategies (e.g., node sizing, pod limits).

• Designing network architecture (e.g., ingress controllers, service meshes, network policies).

• Establishing security policies (e.g., RBAC, pod security standards).

• Ensuring the architecture meets business and technical requirements for scalability, reliability, and compliance.

Breakdown of Other Roles:

• A. Data Scientist
  ❌ Focuses on data analysis and modeling, not infrastructure design.

• B. DevOps Engineer
  🔄 Often implements and automates the infrastructure, but does not typically design the entire architecture.

• C. Site Reliability Engineer (SRE)
  🔄 Focuses on reliability, performance monitoring, and operational aspects. Might contribute to the infrastructure, but isn’t the primary designer.

• D. Security Engineer
  🔐 Focuses on securing the environment, including policies and compliance — typically collaborates with the architect but doesn’t own the overall design.

Explanation:

To ensure reliable and efficient data ingestion from Kafka to Azure Functions, the recommended and most scalable approach is to use Azure Event Hubs, which supports a Kafka-compatible endpoint.

Why Option E is Correct:

• Azure Event Hubs can act as a Kafka broker, allowing you to ingest Kafka messages directly into Azure.

• Azure Functions can then be triggered by Event Hubs, enabling real-time, serverless processing of Kafka messages.

• This avoids the need for custom polling or connectors and leverages fully managed, scalable infrastructure.

Other Options:

• A. Use a custom connector
  ❌ Not optimal — custom connectors add maintenance overhead and reliability concerns.

• B. Use Azure Service Bus
  ❌ Azure Service Bus is not Kafka-compatible. You would need an additional translation layer, which introduces complexity.

• C. Use Azure Data Factory
  ❌ ADF is primarily for batch ETL, not real-time streaming or serverless event processing.

• D. Configure Azure Functions to poll Kafka topics directly
  ❌ Azure Functions do not natively support polling Kafka. This would require running additional infrastructure (e.g., Kafka consumer apps), defeating the purpose of serverless.

✅ Correct Answer:

C. Use both the nodeSelector field and resources field to schedule on GPU-enabled nodes

🔍 Explanation of Each Option:

• A. tolerations ❌
  Tolerations are used to allow Pods to be scheduled on tainted nodes but don’t guarantee access to a GPU or identify GPU-enabled nodes.

• B. affinity ❌
  Node affinity (with preferredDuringScheduling...) helps influence scheduling, but it doesn’t enforce or guarantee GPU availability. It’s a soft rule.

• C. nodeSelector + resources ✅
  This is the correct and recommended approach:

  • nodeSelector: Targets nodes labeled with something like gpu: "true" or accelerator: "nvidia".

  • resources: Specifies GPU requirements, e.g.:

    resources:
limits:
nvidia.com/gpu: 1


  This ensures the Pod only runs on nodes that are both labeled appropriately and have a GPU resource available.

• D. podAffinity ❌
  podAffinity is used to co-locate Pods near each other, but it’s unrelated to requesting specific hardware resources like GPUs.

✅ Correct Answer: B. Database

🔍 Explanation of Each Option:

• A. Deployment ✅
  A valid Kubernetes resource used to manage stateless applications by handling pod creation, scaling, and rolling updates.

• B. Database ❌ (Not Valid)
  Not a built-in Kubernetes resource type.
  Although you might run a database inside a Pod, Kubernetes does not have a native resource type called Database. Managing databases typically requires using StatefulSets, PVCs, or third-party operators.

• C. Ingress ✅
  A valid resource that manages external access to services within the cluster, typically HTTP/HTTPS traffic.

• D. pod ✅
  The smallest and most basic deployable unit in Kubernetes. It represents a single instance of a running process.

• E. Service ✅
  A valid resource that exposes a set of Pods as a network service, enabling stable communication across components.

✅ Correct Answer: A. Only Node1

🔍 Explanation of Each Option:

• A. Only Node1 ✅
  Node1 has the label role: web, which matches the Pod’s nodeSelector. It is the only eligible node.

• B. Only Node3 ❌
  Node3 has no labels. Since nodeSelector requires role: web, this node is excluded.

• C. Only Node2 ❌
  Node2 is labeled role: database, which does not match role: web, so it’s not eligible.

• D. Node1 and Node2 ❌
  Only Node1 matches the role: web label. Node2 does not.

• E. Any of the nodes ❌
  A nodeSelector restricts scheduling to nodes with matching labels. Without a match, nodes are not eligible.

✅ Correct Answer: D. Use a Dockerfile to include the specific Node.js version in the container image for the web application

🔍 Explanation of Each Option:

A. Install Node.js manually on each node ❌
This approach is manual, error-prone, and not scalable. It violates the principles of containerization where dependencies should be included within the container image.

B. Use a Kubernetes init container ❌
Init containers are useful for pre-setup tasks, but installing runtime environments like Node.js dynamically at pod startup adds delay and complexity. It’s not best practice.

C. Define a custom Kubernetes resource ❌
This is unnecessarily complex and not standard for managing application runtime dependencies like Node.js.

D. Use a Dockerfile to include Node.js ✅
This is the best and most standard approach. You define a Dockerfile that uses a base image (like node:18) which guarantees the correct version of Node.js is present inside the container, regardless of the host node.

Example:

FROM node:18
WORKDIR /app
COPY . .
RUN npm install
CMD ["npm", "start"]

E. Use a Helm chart to install Node.js on nodes ❌
Helm is for managing Kubernetes resources, not for installing runtime environments on nodes. Helm should deploy the application that already has Node.js bundled in the container.

✅ Correct Answer: D. StatefulSets

🔍 Explanation of Each Option:

• A. Pods ❌
  A Pod is the basic unit of deployment, but managing multiple Pods manually is not scalable or resilient. Pods do not maintain identity or ordered startup needed for databases.

• B. Deployments ❌
  Deployments are good for stateless applications. However, they don’t guarantee stable network identities or persistent volumes per replica, which are essential for stateful databases.

• C. Services ❌
  A Service is a network abstraction that provides access to a set of Pods, but it doesn’t manage replication or storage configuration.

• D. StatefulSets ✅
  StatefulSets are specifically designed for stateful applications like databases.
  They ensure:

  • Stable, unique network identities (e.g., db-0, db-1, db-2)

  • Persistent storage tied to each replica

  • Ordered, graceful deployment and scaling
    This is ideal for managing multiple database instances with consistency and resilience.

• E. DaemonSets ❌
  A DaemonSet ensures that a copy of a Pod runs on every node, which is not suited for managing a specific number of database replicas.

✅ Correct Answer: B. Deployment

🔍 Explanation of Each Option:

• A. Pod Disruption Budget (PDB) ❌
  PDBs are used to limit voluntary disruptions (like upgrades or drains) by ensuring a minimum number of Pods remain available — they do not automatically replace failed Pods.

• B. Deployment ✅
  A Deployment manages ReplicaSets and ensures the desired number of Pods are running at all times.
  If a Pod fails or is deleted, the Deployment (via its underlying ReplicaSet) will automatically create a new Pod.

• C. Service ❌
  A Service provides network access to Pods but does not manage Pod lifecycle or availability.

• D. Namespace ❌
  A Namespace is just a logical grouping of Kubernetes objects. It does not manage Pods or their replacement.

• E. ReplicaSet ❌
  While a ReplicaSet can replace failed Pods, it is typically managed by a Deployment. You should use a Deployment directly, as it provides additional features like rollbacks and declarative updates.

✅ Correct Answer: B. Services

🔍 Explanation of Each Option:

A. Deployments ❌
A Deployment manages the desired state of application Pods (e.g., number of replicas, rollout strategy) but does not expose them externally. It needs to be paired with a Service or Ingress for exposure.

B. Services ✅
A Service of type LoadBalancer is the correct Kubernetes resource to expose an application to external traffic via a cloud provider’s load balancer. Example:

apiVersion: v1
kind: Service
metadata:
  name: my-service
spec:
  type: LoadBalancer
  selector:
    app: my-app
  ports:
    - protocol: TCP
      port: 80
      targetPort: 8080

C. Ingress ❌
An Ingress is used to manage HTTP(S) traffic routing, often with host/path rules. It requires an Ingress controller and typically works on top of a Service — not as a direct load balancer.

D. ConfigMaps ❌
ConfigMaps are used to store configuration data, not to expose services or handle networking.

E. StatefulSets ❌
StatefulSets are used to manage stateful applications (e.g., databases), but they do not expose applications to external traffic.