Ravindra BagaleCourses & study guides मराठी

Ravi Sir's Cards › DevOps

Chapter 15: Kubernetes Introduction: Cards

मराठी cards · Open the chapter

Revision cards

Why Kubernetes after Compose. Compose runs a stack on one machine. If that machine dies, the app dies.
Revision card 1 of 17: Why Kubernetes after Compose · Download PNG · Open card page

Lesson: 15.1 Why Kubernetes after Compose

Local tool: kind. Learning on a cloud cluster costs money and takes time to set up.
Revision card 2 of 17: Local tool: kind · Download PNG · Open card page

Lesson: 15.2 Primary local tool — kind

Core objects: Pod, Deployment, Service, Namespace. Kubernetes has many objects. Four cover most daily work.
Revision card 3 of 17: Core objects: Pod, Deployment, Service, Namespace · Download PNG · Open card page

Lesson: 15.3 Core objects — Pod, Deployment, Service, Namespace

kubectl everyday verbs. You need a few commands to see and fix anything in a cluster.
Revision card 4 of 17: kubectl everyday verbs · Download PNG · Open card page

Lesson: 15.4 kubectl everyday verbs

Manifest: Deployment + Service for badge-api. Kubernetes reads YAML files that describe what you want.
Revision card 5 of 17: Manifest: Deployment + Service for badge-api · Download PNG · Open card page

Lesson: 15.5 Manifest sketch — Deployment + Service for badge API

Reaching the app: port-forward. Services in kind are inside the cluster, not open on your laptop.
Revision card 6 of 17: Reaching the app: port-forward · Download PNG · Open card page

Lesson: 15.6 Reaching the app — port-forward (kind-friendly)

Rolling update and rollback. Updating all Pods at once causes downtime.
Revision card 7 of 17: Rolling update and rollback · Download PNG · Open card page

Lesson: 15.7 Rolling update and rollback (light)

Probes: readiness vs liveness. Kubernetes can't tell if your app is ready or stuck unless it checks.
Revision card 8 of 17: Probes: readiness vs liveness · Download PNG · Open card page

Lesson: 15.8 Probes — readiness vs liveness (awareness)

Config and Secrets (concepts). Settings inside the image force a rebuild for every change.
Revision card 9 of 17: Config and Secrets (concepts) · Download PNG · Open card page

Lesson: 15.9 Config and secrets — concepts only

Troubleshooting table. Pod statuses look scary, but each points to a known cause.
Revision card 10 of 17: Troubleshooting table · Download PNG · Open card page

Lesson: 15.10 Troubleshooting table

Security basics. A default Pod runs with more power than it needs.
Revision card 11 of 17: Security basics · Download PNG · Open card page

Lesson: 15.11 Security basics (pointer)

Kubernetes anti-patterns. Small shortcuts make clusters unstable.
Revision card 12 of 17: Kubernetes anti-patterns · Download PNG · Open card page

Lesson: 15.12 Anti-patterns

Declarative apply vs imperative run. Commands typed by hand can't be reviewed or repeated.
Revision card 13 of 17: Declarative apply vs imperative run · Download PNG · Open card page

Lesson: 15.12b Declarative apply vs imperative run

Resource requests (awareness). Without requests, Kubernetes can pack too many Pods on one node.
Revision card 14 of 17: Resource requests (awareness) · Download PNG · Open card page

Lesson: 15.12c Resource requests (awareness)

Loading a local image into kind. kind can't see images on your laptop's Docker by default.
Revision card 15 of 17: Loading a local image into kind · Download PNG · Open card page

Lesson: 15.12d Loading a local image into kind (common lab snag)

Namespaces: who can break what. Everything in one place means one mistake hits all.
Revision card 16 of 17: Namespaces: who can break what · Download PNG · Open card page

Lesson: 15.12e Namespaces and who can break what

Lab: kind cluster, deploy, curl. Doing it once yourself makes every interview question easier.
Revision card 17 of 17: Lab: kind cluster, deploy, curl · Download PNG · Open card page

Lesson: 15.13 Lab — kind cluster, deploy, curl

Interview cards

Why use Kubernetes when Docker Compose works? Compose runs on one machine. Kubernetes runs across many, restarts failed containers and scales easily.
Interview card 1 of 17: Why use Kubernetes when Docker Compose works? · Download PNG · Open card page

Lesson: 15.1 Why Kubernetes after Compose

How do you practise Kubernetes locally? Use kind (or minikube): a full small cluster in Docker on your laptop.
Interview card 2 of 17: How do you practise Kubernetes locally? · Download PNG · Open card page

Lesson: 15.2 Primary local tool — kind

What are Pod, Deployment and Service? Pod: runs containers. Deployment: keeps N Pods and does updates. Service: stable address for those Pods.
Interview card 3 of 17: What are Pod, Deployment and Service? · Download PNG · Open card page

Lesson: 15.3 Core objects — Pod, Deployment, Service, Namespace

Which kubectl commands do you use most? get, describe, logs, apply, delete, and rollout.
Interview card 4 of 17: Which kubectl commands do you use most? · Download PNG · Open card page

Lesson: 15.4 kubectl everyday verbs

How does a Service find its Pods? By labels. The Service selector must match the Pod labels in the Deployment template.
Interview card 5 of 17: How does a Service find its Pods? · Download PNG · Open card page

Lesson: 15.5 Manifest sketch — Deployment + Service for badge API

How do you reach an app in kind from your laptop? kubectl port-forward to the Service or Pod, then use localhost.
Interview card 6 of 17: How do you reach an app in kind from your laptop? · Download PNG · Open card page

Lesson: 15.6 Reaching the app — port-forward (kind-friendly)

How do you update and roll back a Deployment? Change the image (set image or apply), watch rollout status, and use rollout undo if needed.
Interview card 7 of 17: How do you update and roll back a Deployment? · Download PNG · Open card page

Lesson: 15.7 Rolling update and rollback (light)

What is the difference between a readiness probe and a liveness probe? Kubernetes runs your app in small units called Pods. A probe is a health check it runs again and again.Readiness = “Can this Pod take traffic now?” If no, traffic stops going to it.Liveness = “Is this app stuck?” If no, Kubernete
Interview card 8 of 17: What is the difference between a readiness probe and a liveness probe? · Download PNG · Open card page

Lesson: 15.8 Probes — readiness vs liveness (awareness)

ConfigMap vs Secret? ConfigMap: normal settings. Secret: sensitive values. Secrets are only base64 by default, so restrict access.
Interview card 9 of 17: ConfigMap vs Secret? · Download PNG · Open card page

Lesson: 15.9 Config and secrets — concepts only

A Pod is in CrashLoopBackOff. What do you do? The app keeps crashing. Check logs --previous, describe events, config and probes.
Interview card 10 of 17: A Pod is in CrashLoopBackOff. What do you do? · Download PNG · Open card page

Lesson: 15.10 Troubleshooting table

How do you make a Pod safer? runAsNonRoot, drop capabilities, read-only root filesystem, resource limits, and RBAC.
Interview card 11 of 17: How do you make a Pod safer? · Download PNG · Open card page

Lesson: 15.11 Security basics (pointer)

Name Kubernetes anti-patterns. Bare Pods, latest tags, no probes, no limits, secrets in Git, everything in default namespace.
Interview card 12 of 17: Name Kubernetes anti-patterns. · Download PNG · Open card page

Lesson: 15.12 Anti-patterns

Declarative vs imperative in Kubernetes? Imperative: commands like kubectl create. Declarative: YAML files applied with kubectl apply, kept in Git.
Interview card 13 of 17: Declarative vs imperative in Kubernetes? · Download PNG · Open card page

Lesson: 15.12b Declarative apply vs imperative run

What are resource requests and limits? Requests: what the Pod reserves, used to place it. Limits: the maximum it may use.
Interview card 14 of 17: What are resource requests and limits? · Download PNG · Open card page

Lesson: 15.12c Resource requests (awareness)

kind says ErrImagePull for my local image. Why? kind nodes don't see your laptop's images. kind load docker-image copies it in.
Interview card 15 of 17: kind says ErrImagePull for my local image. Why? · Download PNG · Open card page

Lesson: 15.12d Loading a local image into kind (common lab snag)

Why use namespaces? To group apps by team or env, and apply RBAC and quotas per group.
Interview card 16 of 17: Why use namespaces? · Download PNG · Open card page

Lesson: 15.12e Namespaces and who can break what

Walk me through deploying an app to a kind cluster. Create cluster, build and load image, apply Deployment + Service, port-forward, curl.
Interview card 17 of 17: Walk me through deploying an app to a kind cluster. · Download PNG · Open card page

Lesson: 15.13 Lab — kind cluster, deploy, curl

Comparison cards

Readiness probe vs Liveness probe. Readiness: can this Pod take traffic now?Liveness: is the app stuck?
Comparison card 1 of 3: Readiness probe vs Liveness probe · Download PNG · Open card page

Lesson: 15.8 Probes — readiness vs liveness (awareness)

ConfigMap vs Secret. ConfigMap: normal settings.Secret: passwords, tokens, keys.
Comparison card 2 of 3: ConfigMap vs Secret · Download PNG · Open card page

Lesson: 15.9 Config and secrets — concepts only

kubectl apply vs kubectl create. apply: makes the cluster match a file; creates or updates.create: makes a new object; fails if it exists.
Comparison card 3 of 3: kubectl apply vs kubectl create · Download PNG · Open card page

Lesson: 15.12b Declarative apply vs imperative run