Kubernetes & Cloud-Native Container Orchestration - Pods, Deployments & Services Flashcards

Question 1

Kubernetes Control Plane Components

Accepted Answer

The master management layer of a K8s cluster consisting of:
- `kube-apiserver`: Exposes the Kubernetes REST API.
- `etcd`: Consistent, distributed key-value store for cluster state.
- `kube-scheduler`: Assigns newly created Pods to optimal worker Nodes.
- `kube-controller-manager`: Runs controller loops to maintain desired state.

Question 2

etcd

Accepted Answer

A strongly consistent, highly available distributed key-value store that acts as Kubernetes' single source of truth. It stores all cluster state data, API object definitions, and metadata.

Question 3

Pod

Accepted Answer

The smallest deployable unit in Kubernetes. A Pod encapsulates one or more co-located containers that share network namespaces (IP address and ports), storage volumes, and container specifications.

Question 4

Sidecar Container Pattern

Accepted Answer

A design pattern where a helper container runs alongside the main application container inside the same Pod. Common uses include log forwarding, monitoring agents, and service mesh proxies (e.g., Envoy).

Question 5

Deployment

Accepted Answer

A declarative Kubernetes workload object used to manage stateless applications. It manages `ReplicaSets` under the hood to handle zero-downtime rolling updates, rollbacks, and pod scaling.

Question 6

ReplicaSet

Accepted Answer

A low-level controller that guarantees a specified number of identical Pod replicas are running at any given time. Usually managed automatically by a higher-level `Deployment` resource.

Question 7

StatefulSet

Accepted Answer

A workload object used for stateful applications (e.g., databases like PostgreSQL or Kafka). It provides unique, persistent network identities (`pod-name-0`), ordered deployment/scaling, and stable persistent storage per replica.

Question 8

DaemonSet

Accepted Answer

A workload controller that ensures a copy of a specific Pod runs on all (or selected) worker Nodes. Ideal for cluster background services such as log collectors (`Fluentd`) and monitoring agents (`Prometheus Node Exporter`).

Question 9

Kubernetes Service (ClusterIP)

Accepted Answer

The default Kubernetes Service type. Exposes the Service on an internal cluster-only IP address, making the workload accessible only from within the cluster network.

Question 10

Kubernetes Service (NodePort)

Accepted Answer

Exposes the Service on each worker Node's IP at a static port (typically in the range `30000-32767`). Automatically routes traffic incoming on `:` to the internal `ClusterIP` service.

Question 11

Kubernetes Service (LoadBalancer)

Accepted Answer

Exposes the Service externally by provisioning an external cloud provider load balancer (e.g., AWS NLB, GCP Load Balancer) that automatically routes traffic to `NodePort` and `ClusterIP` endpoints.

Question 12

Ingress & Ingress Controller

Accepted Answer

- **Ingress**: An API object defining HTTP/HTTPS routing rules (hostnames, paths, TLS certs) to internal services.
- **Ingress Controller**: The reverse proxy daemon (e.g., NGINX, Traefik, HAProxy) that evaluates Ingress rules and routes incoming external traffic.

Question 13

PersistentVolume (PV) vs. PersistentVolumeClaim (PVC)

Accepted Answer

- **PersistentVolume (PV)**: A cluster-wide storage resource provisioned manually or dynamically via a `StorageClass`.
- **PersistentVolumeClaim (PVC)**: A request for storage made by a Pod/user that specifies size, storage class, and access modes (`ReadWriteOnce`, `ReadWriteMany`).

Question 14

kubelet

Accepted Answer

The primary agent running on every worker Node. It accepts `PodSpecs` from the `kube-apiserver` and ensures that the specified containers are created, running, and healthy using the container runtime (e.g., `containerd`).

Question 15

kube-proxy

Accepted Answer

A network proxy that runs on each worker Node. It maintains network rules (via `iptables` or `IPVS`) to allow network communication to Pods from inside or outside of the cluster based on Service specifications.

Question 16

Liveness Probe vs. Readiness Probe

Accepted Answer

- **Liveness Probe**: Checks if the container is alive. If it fails, Kubernetes kills and restarts the container.
- **Readiness Probe**: Checks if the application is ready to accept traffic. If it fails, the Pod is temporarily removed from Service endpoint load balancers.

Question 17

ConfigMap vs. Secret

Accepted Answer

- **ConfigMap**: Stores non-sensitive configuration parameters as plain key-value pairs.
- **Secret**: Stores sensitive operational data (passwords, tokens, keys) encoded in Base64 with enhanced access control standard settings.

Question 18

Container Network Interface (CNI)

Accepted Answer

A standard plugin interface that enables pod-to-pod networking across worker nodes. Popular CNI plugins (e.g., Calico, Flannel, Cilium) ensure every Pod gets a unique, routable IP address without NAT.

Question 19

Deployment Update Strategies: RollingUpdate vs. Recreate

Accepted Answer

- **RollingUpdate** (Default): Progressively replaces old Pods with new ones, ensuring zero downtime (`maxSurge` and `maxUnavailable` control step size).
- **Recreate**: Kills all existing Pods before starting new ones, incurring temporary downtime but preventing concurrent schema/version conflicts.

Question 20

Essential kubectl Diagnostic Commands

Accepted Answer

- `kubectl get `: Lists basic resource status. - `kubectl describe `: Shows detailed specs and recent events for debugging. - `kubectl logs -f `: Streams stdout/stderr logs from container. - `kubectl exec -it -- /bin/sh`: Opens an interactive shell inside a running container.

Kubernetes & Cloud-Native Container Orchestration - Pods, Deployments & Services

Cards in this deck

Related Flashcard Sets

Kubernetes Fundamentals - Container Orchestration & Deployment

TypeScript - Advanced Type Systems, Generics & Design Patterns

Harvard ECON1011 - Intermediate Microeconomics: Game Theory & Market Structures

MIT 18.03 - Differential Equations: Ordinary Differential Equations, Laplace & Fourier