Kubernetes Fundamentals & Container Orchestration Flashcards

Question 1

What is Kubernetes?

Accepted Answer

Kubernetes (K8s) is an open-source container orchestration platform that automates the deployment, scaling, and management of containerized applications. It groups containers into logical units for easy management and discovery.

Question 2

What problem does Kubernetes solve?

Accepted Answer

Kubernetes addresses the complexities of managing containerized applications at scale. It automates tasks like deployment, scaling, self-healing, load balancing, and rolling updates, ensuring high availability and efficient resource utilization.

Question 3

Describe the high-level Kubernetes architecture.

Accepted Answer

Kubernetes operates on a Master-Worker node architecture. The **Master node** (or Control Plane) manages the cluster, while **Worker nodes** (or Minions) run the actual containerized applications.

Question 4

List the key components of a Kubernetes Master Node (Control Plane).

Accepted Answer

The Master node components include: 
1. `kube-apiserver`
2. `etcd`
3. `kube-scheduler`
4. `kube-controller-manager`

Question 5

What is the role of `kube-apiserver`?

Accepted Answer

The `kube-apiserver` is the front-end for the Kubernetes control plane. It exposes the Kubernetes API, allowing communication between various components and external users (via `kubectl`). It's the only component that directly interacts with `etcd`.

Question 6

What is the role of `etcd` in Kubernetes?

Accepted Answer

`etcd` is a consistent and highly available key-value store used as Kubernetes' backing store for all cluster data. It stores the cluster's state, configuration, and metadata.

Question 7

What is the role of `kube-scheduler`?

Accepted Answer

The `kube-scheduler` watches for newly created Pods with no assigned node and selects a node for them to run on. It considers factors like resource requirements, hardware/software/policy constraints, affinity/anti-affinity specifications, and data locality.

Question 8

What is the role of `kube-controller-manager`?

Accepted Answer

The `kube-controller-manager` runs various controller processes that regulate the state of the cluster. Examples include the Node controller, Replication controller, Endpoints controller, and Service Account & Token controllers. It ensures the current state matches the desired state.

Question 9

List the key components of a Kubernetes Worker Node.

Accepted Answer

The Worker node components include: 
1. `kubelet`
2. `kube-proxy`
3. Container Runtime (e.g., Docker, containerd, CRI-O)

Question 10

What is the role of `kubelet`?

Accepted Answer

The `kubelet` is an agent that runs on each worker node. It ensures that containers are running in a Pod, as specified by the PodSpec. It communicates with the `kube-apiserver` to receive instructions and report the node's status.

Question 11

What is the role of `kube-proxy`?

Accepted Answer

The `kube-proxy` runs on each worker node and maintains network rules on the nodes. These rules enable network communication to your Pods from network sessions inside or outside of the cluster. It handles Service abstraction by forwarding requests to the correct Pods.

Question 12

What is a Kubernetes Pod?

Accepted Answer

A Pod is the smallest deployable unit in Kubernetes. It represents a single instance of a running process in your cluster. A Pod typically contains one or more tightly coupled containers that share storage, network, and a unique IP address.

Question 13

What is a Kubernetes Deployment?

Accepted Answer

A Deployment is a higher-level object that manages a set of identical Pods. It provides declarative updates for Pods and ReplicaSets, allowing you to define the desired state (e.g., number of replicas, container image) and Kubernetes will maintain it, handling rolling updates and rollbacks.

Question 14

What is a Kubernetes Service?

Accepted Answer

A Kubernetes Service is an abstraction that defines a logical set of Pods and a policy by which to access them. Services enable network access to a dynamic set of Pods, providing a stable IP address and DNS name, even if Pods are created or destroyed.

Question 15

Explain the `ClusterIP` Service type.

Accepted Answer

A `ClusterIP` Service exposes the Service on an internal IP address within the cluster. It's the default Service type and is only reachable from within the cluster. It's ideal for internal communication between different microservices.

Question 16

Explain the `NodePort` Service type.

Accepted Answer

A `NodePort` Service exposes the Service on each Node's IP at a static port (the `NodePort`). This makes the Service accessible from outside the cluster by requesting `:`. It's often used for development or when a cloud LoadBalancer isn't available.

Question 17

Explain the `LoadBalancer` Service type.

Accepted Answer

A `LoadBalancer` Service exposes the Service externally using a cloud provider's load balancer. The cloud provider provisions a public IP and configures the load balancer to route traffic to the Service. This is the standard way to expose internet-facing applications.

Question 18

What are Kubernetes Namespaces?

Accepted Answer

Namespaces are a way to divide cluster resources among multiple users or teams. They provide a scope for names and allow for logical isolation of resources (e.g., Pods, Deployments, Services) within a single Kubernetes cluster.

Question 19

What is a Kubernetes `ConfigMap`?

Accepted Answer

A `ConfigMap` is an API object used to store non-sensitive configuration data in key-value pairs. It allows you to decouple configuration from application code, making applications more portable. Pods can consume `ConfigMaps` as environment variables, command-line arguments, or files in a volume.

Question 20

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's similar to `ConfigMap` but designed for confidential data. Secrets are base64 encoded by default but not encrypted at rest without additional configuration.

Question 21

What are Kubernetes Volumes?

Accepted Answer

Kubernetes Volumes provide persistent storage for Pods. While containers' filesystems are ephemeral, Volumes allow data to persist across container restarts and even Pod re-scheduling. They are mounted into Pods and can be backed by various storage types (e.g., `emptyDir`, `hostPath`, `PersistentVolumeClaim`).

Question 22

What is `kubectl` and its primary function?

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. It communicates with the `kube-apiserver`.

Question 23

How do you list resources using `kubectl`?

Accepted Answer

You can list various Kubernetes resources using the `kubectl get` command. 
- `kubectl get pods`: Lists all Pods in the current namespace.
- `kubectl get deployments`: Lists all Deployments.
- `kubectl get services -n <namespace>`: Lists Services in a specific namespace.
- `kubectl get all`: Lists common resources (deployments, services, pods, replicasets) in the current namespace.

Question 24

How do you deploy and remove resources using `kubectl`?

Accepted Answer

To deploy or update resources defined in a YAML/JSON file, use `kubectl apply -f `. To remove resources, use `kubectl delete -f ` or `kubectl delete ` (e.g., `kubectl delete pod my-pod`).

Question 25

How do you interact with a running Pod using `kubectl`?

Accepted Answer

You can interact with a running Pod using: - `kubectl exec -it -- /bin/bash`: Executes a command (e.g., `/bin/bash`) inside a container in a Pod, allowing interactive access. - `kubectl logs `: Retrieves the logs from a container in a Pod. - `kubectl logs -f `: Streams logs in real-time.

Kubernetes Fundamentals & Container Orchestration

Cards in this deck

Related Flashcard Sets

Kubernetes - Container Orchestration & Deployment

Kubernetes & Container Orchestration (CKA Fundamentals)

Kubernetes & Container Orchestration Essentials (CKA Prep)

JLPT N5 - Essential Grammar & Kanji