Chanthiraprabu B S

Many of you have asked for Kubernetes notes with hands-on and here are in depth notes which will help you https://lnkd.in/dPvCKUry 1) Clear Any DevOps interview with kubernetes 2) Clear CKAD exam To clear the Certified Kubernetes Application Developer (CKAD) exam, you’ll need to be proficient in core Kubernetes concepts, especially from the perspective of someone building, deploying, and troubleshooting applications within Kubernetes. Here's a structured list of topics to master, aligned with the official exam domains: 🧩 1. Core Concepts (13%) Understand Kubernetes architecture (pods, nodes, clusters, control plane) Create and manage Pods and Deployments Understand multi-container Pod patterns (sidecar, ambassador, adapter) 📦 2. Configuration (18%) Use ConfigMaps and Secrets Understand and set environment variables Work with Kubernetes resource limits and requests Manage application configuration through command-line and manifests 🚀 3. Multi-Container Pods (10%) Design Pods with multiple containers Understand how containers in the same Pod communicate Use shared volumes for communication between containers 🔄 4. Observability (18%) Use kubectl logs, kubectl exec, and kubectl describe for troubleshooting Set up liveness and readiness probes Understand and configure logging and monitoring for Pods 🔁 5. Pod Design (20%) Define Deployments, Jobs, CronJobs Understand Labels, Selectors, and Annotations Use Init containers Define resource limits and affinity/anti-affinity rules Use Taints and Tolerations 📡 6. Services & Networking (13%) Understand ClusterIP, NodePort, LoadBalancer services Use NetworkPolicies Create Ingress resources and configure Ingress controllers Understand DNS in Kubernetes 📤 7. State Persistence (8%) Understand and use Volumes (emptyDir, hostPath, etc.) Use PersistentVolumes (PV) and PersistentVolumeClaims (PVC) Use StorageClasses and dynamic provisioning 🛠️ Tools You Should Be Fluent With: kubectl (must be lightning fast with it!) YAML manifests vim or nano (depending on exam environment, usually vim) Don’t trust?? Watch this here -  https://lnkd.in/dPvCKUry Note - Make sure you like and comment and share this link with your DevOps community 

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Preparing for a DevOps / Cloud / SRE interview? Here’s the list of questions asked in an actual MNC interview Great for both self-prep and team discussions 👇 1. Explain about yourself. 2. 3. 4. Which flavour of Linux you know? Which flavours have you worked. Which version of RHEL , have you worked? How do you locate a file name having a string? How do you do this from root directory? Locate it from sub directory as well. 5. How to search a string within a file? From all the sub directory file as well? 6. Systemd and system init difference or correlation. 7. How to check all serives were up after a system boot? 8. If any services didn’t start, how to troubleshoot? 9. On Aws EC2, how to check applications came up? 10. On AWS, how do you check logs? 11. Where do you configure min and maximum pod? 12. How do you check how many pods were started? 13. What are life cycles of a pod? 14. If any pods were failing to start, how do you start troubleshooting? 15. What are ways database can be installed in aws? 16. Explain on load Balancer in AWS? 17. Explain security groups and NACLs. 18. With example, explain application load balancing and network load balancing. 19. Explain, how do min and max pod configuration In load balancing? 20. How does a kubernetes know when to spin up an additional pod? Give the configuration Details. 21. Explain about cluster in kubernetes. 22. In order to host an enterprise application, what are all things you would consider 23. Ingress and egress configuration. Explain in detail. How would you configure it. 24. How would you configure routing of application to accept ingress. 25. How do you handle database creeds in eks or k8? 26. Explain about secrets and configMap 27. How the configMap is used within application 28. How do you secure transport layer security 29. Across zone load balancing - explain the concept and provide details on how will you configure 30. In aws load balancing, what’s the use of sticky session? hashtag #Linux hashtag #AWS hashtag #Kubernetes hashtag #DevOps hashtag #CloudComputing hashtag #InterviewPreparation hashtag #RHEL hashtag #SystemAdministration hashtag #Containers hashtag #EKS hashtag #Microservices hashtag #CloudSecurity

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“This AWS mistake can cost your client thousands 💸” A junior engineer forgot to set a lifecycle policy on an S3 bucket used for logs. Result? → 4TB of logs piling up silently → Monthly bill shot up by ₹50,000+ → No alerts, no cleanup The fix? ✅ S3 lifecycle rules ✅ Versioning awareness ✅ CloudWatch billing alerts Tech Fact: Over 60% of AWS bills have “silent” charges from underused or forgotten services. #Cloud #learn #careers #personalbranding #growth #AI #DevOps #CloudComputing #SoftwareEngineering #CloudServices #ITAutomation #Technology #DigitalTransformation #motivation #communication

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✍️ Day 23/30 – Horizontal Pod Autoscaler (How Kubernetes Decides to Scale) Let’s start with reality 👇 Traffic is unpredictable. Morning → Low traffic Afternoon → Medium traffic Sale / outage / notification → Traffic spike 🔥 Now ask yourself honestly: > “Do I want to manually scale Pods every time traffic changes?” Of course not. --- 📖 A REAL STORY (Very Common) You deploy an app with: replicas: 2 Everything works fine. Suddenly: CPU usage hits 90% Response time increases Users complain On-call phone rings 📞 You scale manually: replicas: 6 Traffic drops after some time. Now: Pods are idle Resources wasted Cloud bill increases 💸 This back-and-forth is not sustainable. --- 🧠 Kubernetes Asks a Simple Question Kubernetes doesn’t guess. It asks: > “Is the current number of Pods enough for the load?” If NO → add Pods If YES → do nothing If MORE than needed → remove Pods This logic is called Horizontal Pod Autoscaler (HPA). --- 🚦 The Traffic Police Story (Properly Explained) Think of a busy junction 🚦 Light traffic → 1 traffic police Heavy traffic → 3 traffic police Midnight → Reduce staff The police don’t: ❌ Panic ❌ Overreact They observe and adjust gradually. That’s exactly how HPA behaves. --- 🧠 What HPA Actually Uses (Important) HPA does not scale randomly. It uses: CPU usage Memory usage (optional) Custom metrics (advanced) Example idea: > “If average CPU > 70%, add more Pods.” HPA continuously compares: Current load vs Desired load --- 🔁 How Scaling Really Happens 1️⃣ Metrics Server collects data 2️⃣ HPA evaluates thresholds 3️⃣ Kubernetes increases replicas 4️⃣ Services route traffic automatically No downtime. No manual action. No panic. --- ⚠️ VERY IMPORTANT PRODUCTION TRUTH HPA works only if: Resource requests are set Metrics server is running App can scale horizontally No requests → 👉 HPA has nothing to measure ❌ --- 🎯 What HPA Is NOT ❌ It doesn’t scale nodes (that’s Cluster Autoscaler) ❌ It doesn’t fix slow code ❌ It doesn’t replace load testing HPA helps good apps scale better. --- ✅ Final Takeaway > HPA doesn’t chase traffic spikes. It responds calmly to sustained load. That’s why it works in production. --- 💬 What metric do you trust most for autoscaling? CPU Memory Custom metrics Still exploring Comment 👇 --- #DevOps #Kubernetes #hpa #autoscaling #DeploymentStrategies #CloudNative #CI_CD #SRE #ProductionSupport #Automation #TechLearning #30DaysOfKubernetes

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