Q.21 Explain the concept of a Kubernetes ReplicaSet.
A ReplicaSet is a Kubernetes controller that’s primary job is to make sure a specified number of pod replicas (identical copies) are always running.
If pods exit/fail, the ReplicaSet creates new ones. If too many pods exist, it terminates extra ones.
Use Cases:
- Ensuring High Availability: Keeps your application running even with node failures or pod crashes.
- Scaling: Easily increase or decrease the number of replicas to handle varying workloads.
Example:
Q.22 How do you perform rolling updates in Kubernetes?
- Rolling updates are a deployment strategy to update application pods with zero downtime.
- Pods are updated incrementally: a few new version pods are launched, then a few old ones are terminated, in a controlled and gradual manner.
Use Cases:
- Deploying New Code: Roll out new code versions without service interruption.
- Configuration Changes: Apply configuration updates safely.
Example (using kubectl):
kubectl set image deployment/myapp-deployment myapp-container=myapp-image:v2
Q.23 What is a Kubernetes ingress, and how does it work?
- An Ingress is a Kubernetes resource that manages external access (HTTP/HTTPS) to services inside a cluster.
- It works by defining routing rules: incoming traffic is matched against these rules and then sent to the correct service within the cluster.
- An Ingress Controller (e.g., NGINX, Traefik) is needed to interpret Ingress rules and route the traffic
Use Cases:
- Exposing Multiple Services: Provide a single entry point for multiple services running in your cluster.
- Load Balancing: Distribute traffic among different pods of a service.
- TLS Termination: Handle secure HTTPS connections at the Ingress level.
Q.24 Describe the role of a Kubernetes scheduler.
- The Kubernetes scheduler is a key component that decides which available node a new pod should run on.
- It uses factors like:
- Resource Requests: Pods requiring certain amounts of CPU and memory.
- Node Capacity: The resources a node has available.
- Policies: Rules controlling which pods can run on specific nodes.
Use Cases:
- Optimal Placement: Ensures pods are distributed efficiently across the cluster, improving resource utilization.
Q.25 How do you troubleshoot a pod that is not running as expected?
Basic Checks:
kubectl get pods: Check pod’s status (Running, CrashLoopBackOff, etc.)kubectl describe pod <pod-name>: Detailed status, events, recent errors.
Pod Logs:
kubectl logs <pod-name>: View application logs, potentially revealing errors.
Network and Resource Issues:
kubectl get nodes: Verify nodes are healthy and have capacity- Check for relevant pod events to pinpoint root causes.
Part 1- Kubernetes Interview Q & A (Q1-Q5)
Part 2- Kubernetes Interview Q & A (Q6-Q10)
Part 3 – Kubernetes Interview Questions & Answers (Q.11 to Q.15)
Part 4 – Kubernetes Interview Questions & Answers (Q.16 to Q.20)
Hope you find this post helpful.
Telegram: https://t.me/LearnDevOpsForFree
Twitter: https://twitter.com/techyoutbe
Youtube: https://www.youtube.com/@T3Ptech