Kubernetes Orchestration & Cloud-Native Deployment Flashcards

Question 1

What is Kubernetes?

Accepted Answer

An open-source container orchestration system for automating deployment, scaling, and management of containerized applications. It groups containers that make up an application into logical units for easy management and discovery.

Question 2

Explain the concept of a Pod in Kubernetes.

Accepted Answer

A Pod is the smallest deployable unit in Kubernetes, representing a single instance of a running process in a cluster. It encapsulates one or more containers (e.g., Docker containers), storage resources, a unique network IP, and options that govern how the containers should run.

Question 3

What is a Kubernetes Deployment?

Accepted Answer

A Deployment is a higher-level API object that manages the desired state of a set of Pods. It provides declarative updates for Pods and ReplicaSets, enabling rolling updates and rollbacks.

Question 4

How does a ReplicaSet relate to a Deployment?

Accepted Answer

A ReplicaSet ensures a stable set of replica Pods are running at any given time. Deployments manage ReplicaSets, which in turn manage Pods. When you create a Deployment, it automatically creates a ReplicaSet to maintain the specified number of Pod replicas.

Question 5

When would you use a StatefulSet instead of a Deployment?

Accepted Answer

A StatefulSet is used for stateful applications, providing stable, unique network identifiers, stable persistent storage, and ordered, graceful deployment and scaling. Unlike Deployments, StatefulSets maintain a sticky identity for each Pod, which is crucial for databases or message queues.

Question 6

What is a Kubernetes Node?

Accepted Answer

A Node is a worker machine in Kubernetes, which can be a VM or a physical machine. Each Node runs Pods and is managed by the Kubernetes control plane. It contains the necessary services to run Pods, such as a container runtime (e.g., containerd), `kubelet`, and `kube-proxy`.

Question 7

Define a Kubernetes Cluster.

Accepted Answer

A Kubernetes Cluster is a set of Nodes that run containerized applications. It consists of at least one control plane (master) node and multiple worker nodes. The control plane manages the worker nodes and the Pods running on them.

Question 8

What is `kubectl`?

Accepted Answer

`kubectl` is the command-line tool for running commands against Kubernetes clusters. It allows you to deploy applications, inspect and manage cluster resources, and view logs.

Question 9

What is a Kubernetes Service?

Accepted Answer

A Service is an abstract way to expose an application running on a set of Pods as a network service. It provides a stable IP address and DNS name, allowing other applications to discover and communicate with the Pods, even if the Pods' IPs change.

Question 10

Explain the `ClusterIP` Service type.

Accepted Answer

`ClusterIP` is the default Service type. It exposes the Service on an internal IP in the cluster. This type makes the Service only reachable from within the cluster, ideal for internal microservices communication.

Question 11

Describe the `NodePort` Service type.

Accepted Answer

`NodePort` exposes the Service on each Node's IP at a static port (the `NodePort`). A `ClusterIP` Service is automatically created, and the `NodePort` routes to it. This allows external traffic to reach the Service via any Node's IP and the specified `NodePort`.

Question 12

What is the `LoadBalancer` Service type?

Accepted Answer

`LoadBalancer` exposes the Service externally using a cloud provider's load balancer. It automatically provisions a load balancer in the cloud (e.g., AWS ELB, GCP Load Balancer) that routes external traffic to the Service. This type also creates a `NodePort` and `ClusterIP` Service.

Question 13

What is Kubernetes Ingress?

Accepted Answer

Ingress manages external access to services in a cluster, typically HTTP/HTTPS. It provides HTTP routing based on host or path, SSL termination, and load balancing, acting as a layer 7 proxy. An Ingress controller is required to fulfill the Ingress rules.

Question 14

What is a ConfigMap in Kubernetes?

Accepted Answer

A ConfigMap is an API object used to store non-confidential data in key-value pairs. It allows you to decouple configuration artifacts from image content, making applications more portable. ConfigMaps can be consumed by Pods as environment variables, command-line arguments, or as files in a volume.

Question 15

What is a Kubernetes Secret?

Accepted Answer

A Secret is an API object used to store sensitive information, such as passwords, OAuth tokens, and SSH keys. It is similar to a ConfigMap but designed for confidential data. Secrets are base64 encoded by default but not encrypted at rest without additional configuration.

Question 16

Explain PersistentVolume (PV) in Kubernetes.

Accepted Answer

A PersistentVolume (PV) is a piece of storage in the cluster that has been provisioned by an administrator or dynamically provisioned using Storage Classes. It is a resource in the cluster, independent of any Pod, and represents actual storage capacity (e.g., NFS, iSCSI, cloud-provider-specific storage).

Question 17

What is a PersistentVolumeClaim (PVC)?

Accepted Answer

A PersistentVolumeClaim (PVC) is a request for storage by a user. It consumes PV resources. PVCs specify the desired size, access mode (e.g., ReadWriteOnce, ReadOnlyMany), and storage class, and Kubernetes binds a suitable PV to the PVC.

Question 18

How do you list resources using `kubectl`?

Accepted Answer

Use `kubectl get` followed by the resource type.
Example: `kubectl get pods`, `kubectl get deployments`, `kubectl get svc`

Question 19

How do you get detailed information about a Kubernetes resource?

Accepted Answer

Use `kubectl describe` followed by the resource type and name.
Example: `kubectl describe pod my-pod-xyz`

Question 20

How do you deploy or update resources using `kubectl`?

Accepted Answer

Use `kubectl apply -f <filename.yaml>`. This command creates or updates resources based on the configuration defined in the YAML file.

Question 21

How do you delete a Kubernetes resource?

Accepted Answer

Use `kubectl delete` followed by the resource type and name, or by specifying a YAML file.
Example: `kubectl delete pod my-pod-xyz` or `kubectl delete -f <filename.yaml>`

Question 22

How do you view logs from a Pod's container?

Accepted Answer

Use `kubectl logs [-c ]`. Example: `kubectl logs my-app-pod-12345-abcde`

Question 23

How do you execute a command inside a running Pod's container?

Accepted Answer

Use `kubectl exec -it [-c ] -- `. Example: `kubectl exec -it my-app-pod-12345-abcde -- /bin/bash`

Kubernetes Orchestration & Cloud-Native Deployment

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