deVops pathshala Blog – Notes for Me & You

  Subscribe YouTube Channel @devops-pathshal a   1. What is Docker ? Ans:- Docker is a platform that allows you to package an application and all its dependencies into lightweight portable containers. 2. What are Containers ? Ans:- Containers are lightweight, isolated environment that package an application along with all dependencies so it run consistently on any system. 3. What is the difference between a container and a Virtual Machine ? Ans:- Containers are lightweight because they share the host operating system, while virtual machine are heavy because they run their own full operating system. Containers start very quickly, use fewer resources and are ideal for microservices. Virtual machines provide stronger isolation but require more RAM and CPU since each VM containers a full OS. So overall, containers are fast and efficient, whereas VMs are heavier but more isolated. 4. What are docker engine ? Ans:- Docker Engine is the core component of  Docker that runs and ma...

                                                                    Docker Image Management  A docker image is a read only blue print used to create containers. It contains the application code, dependencies and environment required to run the containers.                                              Image vs Container  Feature Docker Image Docker Container Definition Read-only template used to create containers  Running instance of a Docker image State Static (does not change) Dynamic (changes during runtime) Purpose Used to build containers Used to run applications Mutability Immutable (cannot be modified) Mutable (can be modified) Storage Stored on disk Runs in memory + disk Creation Creat...

  🟢 Basic Kubernetes Interview Questions What is Kubernetes? Why do we use Kubernetes? Difference between Docker and Kubernetes? What is a Pod in Kubernetes? What is a Node in Kubernetes? What is a Namespace? What is a Deployment in Kubernetes? What is a Service in Kubernetes? Types of Services in Kubernetes? What is a Kubelet? What is a Kubernetes Master Node? What are Labels and Selectors? What is ReplicaSet? What is the difference between ReplicaSet and Deployment? What is kubectl? (common commands) What are ConfigMaps? What are Secrets? Difference between Secret and ConfigMap? What is ETCD? What is Scheduler? What is Container Runtime in Kubernetes? 🟡 Intermediate Kubernetes Questions Difference between NodePort, ClusterIP, LoadBalancer? What is Ingress and Ingress Controller? What is Horizontal Pod Autoscaler (HPA)? What are taints and tolerations? What is Node Affinity vs Pod Affinity? What is DaemonSet? What is StatefulSet? Difference between StatefulSet and Deployment? Wh...

  🔹 Linux Networking – Basic to Advanced Questions ✅ Basic Level 1.What is the difference between IP address, Subnet mask, and Gateway? 2.How do you check your system’s IP address in Linux? (commands) 3.Difference between ifconfig and ip addr command. 4.How do you check active network connections in Linux? 5.What is the difference between TCP and UDP? Give examples. 6.How to test connectivity between two systems? (ping, telnet, nc). 7.What is the use of /etc/hosts file in Linux? 8.What is the difference between public IP and private IP? 9.How do you check open ports on a Linux system? ✅ Intermediate Level 10.What is the difference between switch, router, and bridge in networking? 11.What is DNS? How do you check DNS resolution in Linux? 12.Explain the difference between static IP and DHCP. 13.What is ARP? How to check ARP table in Linux? 14.What is the use of /etc/resolv.conf file? 15.How do you trace the path packets take to a destination? 16.What is netstat command? Why is it re...

  • Computer Networking refers to interconnected computing devices that can exchange date and share resource with each other. Hardware Requirements    • Etherent Card, NIC, Interface, Lan Card  • Cables (wireless/wired)  • Networking Devices (HUB/Switch/Router)  Logical Terms   • IP Address (Public,Private,static,Dynamic,Virtual)   • Mac Address   • Source & Destination Address   • Ports, Sockets  • Network Address, Broadcast Address Mac address:- Mac address is the physical address , which uniqualy identifies each devices on a given network. It’s persistent.  IP address:- IP address stand for “Internet Protocol Address”. The inetenet protocol is a set of rule for communication over the internet. • Type of IP addres   1. IPv4 (Internet Protocol Version 4)   2. IPv6 (Internet Protocol Version 6)  IPv4 = 32 bit   IPv6 = 128 bit Bit = 0,1   *IPv4 = 32 bit 4 octats...

  1. docker –version --> to check docker version   2. docker version --> to check client and host version    3. docker container run httpd --> create container foreground   4. docker container run –d httpd --> create container byground  5. docker container ls --> to show only running container    6. docker container la –a --> to show all container   7. docker ps --> to show container   8. docker container stop container name --> to stop container  9. docker container start container name --> to statr container    10. docker container rm container name --> to delete stop container    11. docker container rm –f container name --> to delete running container   12. docker container run –d –it ubuntu --> to create OS image  13. docker image ls --> to show images   14. docker container run –d –name team httpd --> naming the...

1. Docker Client: a. This is where the user interacts with Docker using commands like docker build, docker run, docker pull, etc. b. It sends these commands to the Docker Daemon.   2. Docker Daemon (dockerd):  a. This is the background service that actually performs all Docker operations like building images, running containers, and communicating with the Docker registry.  b. It listens to the Docker Client's requests and manages Docker objects.  3. Dockerfile:  a. A text file that contains a set of instructions to create a Docker image.   b. The Docker Daemon reads this file to build a Docker image using the docker build command.   4. Docker Image:  a. A read-only template that contains the application code, runtime, libraries, and dependencies.  b. This is built from the Dockerfile and used to launch containers.   5. Docker Container:   a. A running instance of a Docker image.  b. It is isola...

   Are you confused about where to start your DevOps journey? This post will help you understand the complete DevOps learning path step by step. The roadmap image below shows all the important tools and concepts you should learn to become a successful DevOps Engineer in 2025 and beyond. ✅ What this roadmap covers: The correct learning order – from basics to advanced Most essential tools every DevOps engineer must know Cloud, container, automation, and CI/CD topics Real-world skills needed for job readiness 📌 Key Learning Stages: Linux Fundamentals – The base of every DevOps journey Version Control – Git & GitHub Scripting – Shell scripting and Python basics Containers – Docker and containerization Orchestration – Kubernetes fundamentals Cloud – AWS (or any major cloud provider) Configuration Management – Ansible Infrastructure as Code – Terraform CI/CD – Jenkins, GitHub Actions Monitoring & Logging – Prometheus, Grafana, ELK stack 🎯 How to use this roadmap: Don’t try...

                                                   LINUX BASIC COMMANDS                                           1. whoami - Display the current logged-in user.                    whoami - Shows username.                    Example: whoami  2. pwd - Print the current directory path.                pwd - Outputs the current directory.  Example: pwd  3. . ls - Lists directory contents.             ls - Basic list.             ls -l - List with details.             Example: ls -la Directory  4. . cd - Chan...