├── pod-service.yml ├── service.yml ├── name-space.yml ├── minikube-stepup-psa.md ├── eks-setup-psa.md ├── psa-Jenkins-Docker-K8S.md └── Kubernetes-psa-notes.txt /pod-service.yml: -------------------------------------------------------------------------------- 1 | --- 2 | apiVersion: v1 3 | kind: Pod 4 | metadata: 5 | name: testpod 6 | labels: 7 | app: demoapp 8 | spec: 9 | containers: 10 | - name: test 11 | image: psait/pankajsiracademy:latest 12 | ports: 13 | - containerPort: 9090 14 | ... 15 | -------------------------------------------------------------------------------- /service.yml: -------------------------------------------------------------------------------- 1 | --- 2 | apiVersion: v1 3 | kind: Service 4 | metadata: 5 | name: testpod-service 6 | spec: 7 | type: NodePort 8 | selector: 9 | app: demoapp # This must match the Pod's label 10 | ports: 11 | - port: 80 # Exposed port for external access 12 | targetPort: 9090 # Port on which the app is running inside the container 13 | nodePort: 30080 # External port exposed on each node 14 | ... -------------------------------------------------------------------------------- /name-space.yml: -------------------------------------------------------------------------------- 1 | --- 2 | apiVersion: v1 3 | kind: Namespace 4 | metadata: 5 | name: psait-ns 6 | --- 7 | apiVersion: v1 8 | kind: Pod 9 | metadata: 10 | name: testpod 11 | namespace: psait-ns 12 | labels: 13 | app: demoapp 14 | spec: 15 | containers: 16 | - name: webappcontainer 17 | image: psait/pankajsiracademy:latest 18 | ports: 19 | - containerPort: 9090 20 | --- 21 | apiVersion: v1 22 | kind: Service 23 | metadata: 24 | name: test-service 25 | namespace: psait-ns 26 | spec: 27 | type: NodePort 28 | selector: 29 | app: demoapp 30 | ports: 31 | - port: 80 32 | targetPort: 9090 33 | nodePort: 30070 34 | ... -------------------------------------------------------------------------------- /minikube-stepup-psa.md: -------------------------------------------------------------------------------- 1 | ## Step-1 : Setup Linux VM 2 | 3 | 1) Login into AWS Cloud account 4 | 2) Create Linux VM with Ubuntu AMI (t2.medium or t3.medium) 5 | 3) Select Storage as 50 GB (Default is 8 GB only for Linux) 6 | 2) Create Linux VM and connect to it using SSH Client 7 | 8 | ## Step-2 : Install Docker In Ubuntu VM 9 | 10 | ``` 11 | sudo apt update 12 | curl -fsSL get.docker.com | /bin/bash 13 | sudo usermod -aG docker ubuntu 14 | exit 15 | ``` 16 | ## Step-3 : Updating system packages and installing Minikube dependencies 17 | 18 | ``` 19 | sudo apt update 20 | sudo apt install -y curl wget apt-transport-https 21 | 22 | ``` 23 | 24 | ## Step-4 : Installing Minikube 25 | 26 | ``` 27 | curl -LO https://storage.googleapis.com/minikube/releases/latest/minikube-linux-amd64 28 | 29 | sudo install minikube-linux-amd64 /usr/local/bin/minikube 30 | 31 | minikube version 32 | ``` 33 | 34 | ## Step-5 : Install Kubectl (Kubernetes Client) 35 | 36 | ``` 37 | curl -LO https://storage.googleapis.com/kubernetes-release/release/$(curl -s https://storage.googleapis.com/kubernetes-release/release/stable.txt)/bin/linux/amd64/kubectl 38 | chmod +x kubectl 39 | sudo mv kubectl /usr/local/bin/ 40 | kubectl version -o yaml 41 | ``` 42 | 43 | ## Step-6 : Start MiniKube Server 44 | 45 | ``` 46 | minikube start — driver=docker 47 | ``` 48 | 49 | ## Step-7 : Check MiniKube status 50 | 51 | ``` 52 | minikube status 53 | ``` 54 | 55 | ## Step-8 : Access K8S Cluster 56 | 57 | ``` 58 | kubectl cluster-info 59 | ``` 60 | 61 | ## Step-9 : Access K8S Nodes 62 | 63 | ``` 64 | kubectl get nodes 65 | ``` 66 | 67 | 68 | -------------------------------------------------------------------------------- /eks-setup-psa.md: -------------------------------------------------------------------------------- 1 | # Step - 1 : Create EKS Management Host in AWS # 2 | 3 | 1) Launch new Ubuntu VM using AWS Ec2 ( t2.micro ) 4 | 2) Connect to machine and install kubectl using below commands 5 | ``` 6 | curl -o kubectl https://amazon-eks.s3.us-west-2.amazonaws.com/1.19.6/2021-01-05/bin/linux/amd64/kubectl 7 | chmod +x ./kubectl 8 | sudo mv ./kubectl /usr/local/bin 9 | kubectl version --short --client 10 | ``` 11 | 3) Install AWS CLI latest version using below commands 12 | ``` 13 | sudo apt install unzip 14 | curl "https://awscli.amazonaws.com/awscli-exe-linux-x86_64.zip" -o "awscliv2.zip" 15 | unzip awscliv2.zip 16 | sudo ./aws/install 17 | aws --version 18 | ``` 19 | 20 | 4) Install eksctl using below commands 21 | ``` 22 | curl --silent --location "https://github.com/weaveworks/eksctl/releases/latest/download/eksctl_$(uname -s)_amd64.tar.gz" | tar xz -C /tmp 23 | sudo mv /tmp/eksctl /usr/local/bin 24 | eksctl version 25 | ``` 26 | # Step - 2 : Create IAM role & attach to EKS Management Host # 27 | 28 | 1) Create New Role using IAM service ( Select Usecase - ec2 ) 29 | 2) Add below permissions for the role
30 | - Administrator - acces
31 | 32 | 3) Enter Role Name (eksrole) 33 | 4) Attach created role to EKS Management Host (Select EC2 => Click on Security => Modify IAM Role => attach IAM role we have created) 34 | 35 | # Step - 3 : Create EKS Cluster using eksctl # 36 | **Syntax:** 37 | 38 | eksctl create cluster --name cluster-name \ 39 | --region region-name \ 40 | --node-type instance-type \ 41 | --nodes-min 2 \ 42 | --nodes-max 2 \ 43 | --zones , 44 | 45 | ## N. Virgina:
46 | ` 47 | eksctl create cluster --name psait-cluster4 --region us-east-1 --node-type t2.medium --zones us-east-1a,us-east-1b 48 | ` 49 | ## Mumbai:
50 | ` 51 | eksctl create cluster --name psait-cluster4 --region ap-south-1 --node-type t2.medium --zones ap-south-1a,ap-south-1b 52 | ` 53 | 54 | ## After cluster created we can check nodes using below command. 55 | 56 | ` 57 | kubectl get nodes 58 | ` 59 | 60 | # Note: We should be able to see EKS cluster nodes here.** 61 | 62 | # We are done with our Setup # 63 | 64 | # Step - 4 : After your practise, delete Cluster and other resources we have used in AWS Cloud to avoid billing # 65 | 66 | ``` 67 | eksctl delete cluster --name psait-cluster4 --region ap-south-1 68 | ``` 69 | -------------------------------------------------------------------------------- /psa-Jenkins-Docker-K8S.md: -------------------------------------------------------------------------------- 1 | # Creating Ci/CD pipeline using following tools 2 | 1) Maven 3 | 2) Git Hub 4 | 3) Jenkins 5 | 4) Docker 6 | 5) Kubernetes 7 | 8 | # Step - 1 : Create EKS Management Host in AWS # 9 | 10 | 1) Launch new Ubuntu VM using AWS Ec2 ( t2.micro ) 11 | 2) Connect to machine and install kubectl using below commands 12 | ``` 13 | curl -o kubectl https://amazon-eks.s3.us-west-2.amazonaws.com/1.19.6/2021-01-05/bin/linux/amd64/kubectl 14 | chmod +x ./kubectl 15 | sudo mv ./kubectl /usr/local/bin 16 | kubectl version --short --client 17 | ``` 18 | 3) Install AWS CLI latest version using below commands 19 | ``` 20 | sudo apt install unzip 21 | curl "https://awscli.amazonaws.com/awscli-exe-linux-x86_64.zip" -o "awscliv2.zip" 22 | unzip awscliv2.zip 23 | sudo ./aws/install 24 | aws --version 25 | ``` 26 | 27 | 4) Install eksctl using below commands 28 | ``` 29 | curl --silent --location "https://github.com/weaveworks/eksctl/releases/latest/download/eksctl_$(uname -s)_amd64.tar.gz" | tar xz -C /tmp 30 | sudo mv /tmp/eksctl /usr/local/bin 31 | eksctl version 32 | ``` 33 | 34 | # Step - 2 : Create IAM role & attach to EKS Management Host & Jenkins Server # 35 | 36 | 1) Create New Role using IAM service ( Select Usecase - ec2 ) 37 | 2) Add below permissions for the role
38 | - IAM - fullaccess
39 | - VPC - fullaccess
40 | - EC2 - fullaccess
41 | - CloudFomration - fullaccess
42 | - Administrator - acces
43 | 44 | 3) Enter Role Name (eksrole) 45 | 4) Attach created role to EKS Management Host (Select EC2 => Click on Security => Modify IAM Role => attach IAM role we have created) 46 | 5) Attach created role to Jenkins Machine (Select EC2 => Click on Security => Modify IAM Role => attach IAM role we have created) 47 | 48 | # Step - 3 : Create EKS Cluster using eksctl # 49 | **Syntax:** 50 | 51 | eksctl create cluster --name cluster-name \ 52 | --region region-name \ 53 | --node-type instance-type \ 54 | --nodes-min 2 \ 55 | --nodes-max 2 \ 56 | --zones , 57 | 58 | ``` 59 | eksctl create cluster --name psait-cluster --region ap-south-1 --node-type t2.medium --zones ap-south-1a,ap-south-1b 60 | ``` 61 | 62 | 63 | ``` 64 | kubectl get nodes 65 | ``` 66 | 67 | # Step-4 : Jenkins Server Setup in Linux VM # 68 | 69 | 1) Create Ubuntu VM using AWS EC2 (t2.medium)
70 | 2) Enable 8080 Port Number in Security Group Inbound Rules 71 | 3) Connect to VM using MobaXterm 72 | 4) Install Java 73 | 74 | ``` 75 | sudo apt update 76 | sudo apt install fontconfig openjdk-17-jre 77 | java -version 78 | ``` 79 | 80 | 5) Install Jenkins 81 | ``` 82 | sudo wget -O /usr/share/keyrings/jenkins-keyring.asc \ 83 | https://pkg.jenkins.io/debian-stable/jenkins.io-2023.key 84 | echo deb [signed-by=/usr/share/keyrings/jenkins-keyring.asc] \ 85 | https://pkg.jenkins.io/debian-stable binary/ | sudo tee \ 86 | /etc/apt/sources.list.d/jenkins.list > /dev/null 87 | sudo apt-get update 88 | sudo apt-get install jenkins 89 | ``` 90 | 6) Start Jenkins 91 | 92 | ``` 93 | sudo systemctl enable jenkins 94 | sudo systemctl start jenkins 95 | ``` 96 | 97 | 7) Verify Jenkins 98 | 99 | ``` 100 | sudo systemctl status jenkins 101 | ``` 102 | 103 | 8) Open jenkins server in browser using VM public ip 104 | 105 | ``` 106 | http://public-ip:8080/ 107 | ``` 108 | 109 | 9) Copy jenkins admin pwd 110 | ``` 111 | sudo cat /var/lib/jenkins/secrets/initialAdminPassword 112 | ``` 113 | 114 | 10) Create Admin Account & Install Required Plugins in Jenkins 115 | 116 | 117 | ## Step-5 : Configure Maven as Global Tool in Jenkins ## 118 | 1) Manage Jenkins -> Tools -> Maven Installation -> Add maven
119 | 120 | ## Step-6 : Setup Docker in Jenkins ## 121 | ``` 122 | curl -fsSL get.docker.com | /bin/bash 123 | sudo usermod -aG docker jenkins 124 | sudo systemctl restart jenkins 125 | sudo docker version 126 | ``` 127 | # Step - 8 : Install AWS CLI in JENKINS Server # 128 | 129 | URL : https://docs.aws.amazon.com/cli/latest/userguide/getting-started-install.html 130 | 131 | **Execute below commands to install AWS CLI** 132 | ``` 133 | sudo apt install unzip 134 | curl "https://awscli.amazonaws.com/awscli-exe-linux-x86_64.zip" -o "awscliv2.zip" 135 | unzip awscliv2.zip 136 | sudo ./aws/install 137 | aws --version 138 | ``` 139 | 140 | # Step - 9 : Install Kubectl in JENKINS Server # 141 | **Execute below commands in Jenkins server to install kubectl** 142 | 143 | ``` 144 | curl -o kubectl https://amazon-eks.s3.us-west-2.amazonaws.com/1.19.6/2021-01-05/bin/linux/amd64/kubectl 145 | chmod +x ./kubectl 146 | sudo mv ./kubectl /usr/local/bin 147 | kubectl version --short --client 148 | ``` 149 | 150 | # Step - 10 : Update EKS Cluster Config File in Jenkins Server # 151 | 152 | 1) Execute below command in Eks Management host & copy kube config file data
153 | $ cat .kube/config 154 | 155 | 2) Execute below commands in Jenkins Server and paste kube config file
156 | $ cd /var/lib/jenkins
157 | $ sudo mkdir .kube
158 | $ sudo vi .kube/config
159 | 160 | 3) Execute below commands in Jenkins Server and paste kube config file for ubuntu user to check EKS Cluster info
161 | $ cd ~
162 | $ ls -la
163 | $ sudo vi .kube/config
164 | 165 | 4) check eks nodes
166 | $ kubectl get nodes 167 | 168 | **Note: We should be able to see EKS cluster nodes here.** 169 | 170 | # Step - 11 : Create Jenkins CI CD Job # 171 | 172 | - **Stage-1 : Clone Git Repo**
173 | - **Stage-2 : Maven Build**
174 | - **Stage-3 : Create Docker Image**
175 | - **Stage-4 : Push Docker Image to Registry**
176 | - **Stage-5 : Deploy app in k8s eks cluster**
177 | 178 | ``` 179 | pipeline { 180 | agent any 181 | 182 | tools{ 183 | maven "Maven-3.9.9" 184 | } 185 | 186 | stages { 187 | stage('Clone Repo') { 188 | steps { 189 | git 'https://github.com/pankajmutha14/docker-test.git' 190 | } 191 | } 192 | stage('Maven Build') { 193 | steps { 194 | sh 'mvn clean package' 195 | } 196 | } 197 | stage('Docker Image') { 198 | steps { 199 | sh 'docker build -t psait/pankajsiracademy:latest .' 200 | } 201 | } 202 | stage('k8s deployment') { 203 | steps { 204 | sh 'kubectl apply -f k8s-deploy.yml' 205 | } 206 | } 207 | } 208 | } 209 | 210 | ``` 211 | 212 | # Step - 12 : Access Application in Browser # 213 | - **We should be able to access our application**
214 | URL : http://LBR/context-path/ 215 | 216 | 217 | 218 | -------------------------------------------------------------------------------- /Kubernetes-psa-notes.txt: -------------------------------------------------------------------------------- 1 | ################################## 2 | Docker & Kubernetes Overview 3 | ################################## 4 | 5 | What is Docker? 6 | 7 | Docker is a free and open-source containerization software that allows you to package applications along with their dependencies into a single unit called a Docker Image. This image can run on any system that has Docker installed, making deployment easy and consistent across different environments. 8 | 9 | Why use Docker? 10 | 11 | ✅ Portability – Run the same application on any machine, regardless of OS configuration. 12 | ✅ Dependency Management – Ensures that all required software (e.g., libraries, databases, and runtimes) is included within the image. 13 | ✅ Fast Deployment – No need to manually install dependencies every time you set up a new environment. 14 | ✅ Resource Efficiency – Uses fewer resources compared to traditional virtual machines. 15 | 16 | ###################### 17 | How Docker Works? 18 | ###################### 19 | Create a Docker Image – Package the app code + dependencies into a lightweight container image. 20 | 21 | Run the Docker Container – Deploy this image as a container using the docker run command. 22 | 23 | Execute Anywhere – The same image runs on any machine with Docker installed. 24 | 25 | Once the image is built, it can run on any machine without requiring additional software setup. 26 | ____________________________________________________________________________________________________________________ 27 | 28 | ############################################### 29 | Kubernetes (Container Orchestration Software) 30 | ############################################### 31 | 32 | What is Kubernetes? 33 | 34 | Kubernetes (K8s) is a free and open-source orchestration tool developed by Google to manage containerized applications. 35 | 36 | 💡 Orchestration = Managing multiple containers efficiently 37 | 38 | Kubernetes automates key tasks like: 39 | 40 | 1. Creating, starting, and stopping containers. 41 | 42 | 2. Scaling up/down based on demand. 43 | 44 | 3. Handling failures automatically. 45 | 46 | 47 | ###################### 48 | Why use Kubernetes? 49 | ###################### 50 | 51 | ✅ Orchestration – Efficiently manages multiple containers across a cluster of machines. 52 | ✅ Self-Healing – If a container crashes, Kubernetes automatically replaces it. 53 | ✅ Load Balancing – Distributes traffic across multiple containers to avoid overloading. 54 | ✅ Auto Scaling – Increases or decreases the number of running containers based on traffic load. 55 | ✅ Automated Deployments – Supports CI/CD for rolling updates and version control. 56 | 57 | Kubernetes Advantages (Detailed Explanation) 58 | 1) Orchestration – Managing Containers 59 | Kubernetes helps manage multiple Docker containers across different machines (nodes) efficiently. 60 | 61 | 🔹 Instead of running docker run manually for each container, Kubernetes automates deployment. 62 | 🔹 It ensures that all containers are running smoothly and adjusts their status as needed. 63 | 64 | Note: Kubernetes ensures all these containers are running, healthy, and communicating with each other properly. 65 | 66 | 2) Self-Healing – Automatic Recovery 67 | If a container crashes due to an error or system failure, Kubernetes automatically restarts a new instance. 68 | 69 | 📌 Example: 70 | 71 | A web server container (Apache, Nginx) stops unexpectedly. 72 | 73 | Kubernetes detects the failure and starts a new container to replace it. 74 | 75 | Users never notice downtime. 76 | 77 | 3) Load Balancing – Distributes Traffic Efficiently 78 | Kubernetes distributes incoming user requests across multiple containers to avoid overloading any single instance. 79 | 80 | 📌 Example: 81 | 82 | A shopping website experiences high traffic during a sale. 83 | 84 | Kubernetes ensures that requests are evenly distributed across available backend servers. 85 | 86 | Prevents server crashes and ensures smooth performance. 87 | 88 | 4) Auto Scaling – Adjusting Resources Dynamically 89 | Kubernetes can increase or decrease the number of containers automatically based on traffic load. 90 | 91 | 📌 Example: 92 | 93 | If website traffic increases, Kubernetes adds more containers to handle the load. 94 | 95 | If traffic reduces, Kubernetes removes extra containers to save resources. 96 | 97 | Works similarly to cloud-based Auto Scaling Groups (ASG). 98 | 99 | Conclusion 100 | 🚀 Docker simplifies packaging applications into portable containers. 101 | 🚀 Kubernetes ensures these containers are orchestrated, scalable, and reliable. 102 | 103 | Together, Docker & Kubernetes enable modern cloud-native application deployment—making applications highly available, efficient, and automated. 104 | 105 | ######################################################### 106 | Kubernetes (K8s) Architecture - Explained in Detail 107 | ######################################################### 108 | 109 | 1) Control Plane (Master Node/Control Node) 110 | -> The control plane is responsible for managing the Kubernetes cluster. It includes the following components: 111 | 112 | 1. API Server: Receives requests from kubectl and manages cluster operations. 113 | 114 | 2. Scheduler: Identifies pending tasks in ETCD and assigns them to worker nodes. 115 | 116 | 3. Controller Manager: Ensures the cluster’s desired state matches the actual state. 117 | 118 | 4. ETCD: A distributed key-value store that acts as Kubernetes' internal database. 119 | 120 | 2) Worker Nodes (Slave Nodes) 121 | -> Worker nodes run application workloads. They include the following components: 122 | 123 | 1. Kubelet: A node agent that communicates with the control plane and manages containers. 124 | 125 | 2. Kube Proxy: Manages networking and ensures communication within the cluster. 126 | 127 | 3. Docker Engine: Runs and manages containerized applications. 128 | 129 | 4. Pod: The smallest deployable unit in Kubernetes, housing one or more containers. 130 | 131 | 5. Container: Runs inside a Pod and contains the application code. 132 | 133 | #################################### 134 | Explanation k8S working 135 | #################################### 136 | 137 | Step 1: To deploy an application, we interact with the control plane using the kubectl CLI. 138 | 139 | Step 2: The API Server receives the request and stores it in ETCD with a pending status. 140 | 141 | Step 3: The Scheduler identifies an available worker node to execute the task, using Kubelet for node management. 142 | 143 | Step 4: The Kubelet ensures the worker node is running the assigned workload. 144 | 145 | Step 5: The Kube Proxy manages networking for seamless cluster communication. 146 | 147 | Step 6: The Controller Manager continuously monitors the cluster to ensure tasks run correctly. 148 | 149 | ########## 150 | Note: 151 | ########## 152 | 153 | -> A cluster in Kubernetes (K8s) refers to a group of servers (nodes) that work together to run containerized applications. It consists of: 154 | 155 | a. Control Plane (Master Node) – Manages and controls the cluster. 156 | 157 | b. Worker Nodes (Slave Nodes) – Run application workloads inside containers. 158 | 159 | ################################### 160 | Kubernetes (K8s) Cluster Setup 161 | #################################### 162 | 163 | A Kubernetes Cluster is a group of servers working together to run containerized applications. It can be set up in two main ways: 164 | 165 | A Kubernetes Cluster = Control Plane + Worker Nodes + Pods + Resources + Networking + Storage 166 | 167 | 1) Self-Managed Cluster 168 | In this setup, we manually install and manage Kubernetes on our own infrastructure. 169 | 170 | a) MiniKube (Single Node) 171 | -> Runs a single-node cluster on a local machine. 172 | -> Best for learning and practicing Kubernetes concepts. 173 | -> Not suitable for production as it lacks high availability and scalability. 174 | 175 | b) Kubeadm (Multi-Node) 176 | -> A tool for setting up a multi-node cluster manually. 177 | -> Requires configuring the control plane, worker nodes, and networking. 178 | -> Gives full control over the cluster but requires deep Kubernetes expertise. 179 | -> Used for on-premise or customized Kubernetes deployments. 180 | 181 | 2) Cloud Provider-Managed Cluster (Pre-configured, ready-to-use) 182 | Cloud providers offer fully managed Kubernetes services, where they handle cluster maintenance, updates, and availability. 183 | 184 | a) AWS EKS (Elastic Kubernetes Service) 185 | -> A managed Kubernetes service on Amazon Web Services. 186 | 187 | b) Azure AKS (Azure Kubernetes Service) 188 | -> Microsoft Azure’s managed Kubernetes offering. 189 | 190 | 191 | c) GCP GKE (Google Kubernetes Engine) 192 | -> Google Cloud’s fully managed Kubernetes solution. 193 | 194 | ######################### 195 | MiniKube Setup 196 | ####################### 197 | 198 | Step-1 : Setup Linux VM 199 | 200 | Login into AWS Cloud account 201 | Create Linux VM with Ubuntu AMI - t2.medium 202 | Select Storage as 50 GB or more with 2 vCPU required minimum(Default is 8 GB only for Linux) 203 | Create Linux VM and connect to it using SSH Client 204 | 205 | 206 | Step-2 : Install Docker In Ubuntu VM 207 | 208 | sudo apt update 209 | curl -fsSL get.docker.com | /bin/bash 210 | sudo usermod -aG docker ubuntu 211 | exit 212 | 213 | Step-3 : Updating system packages before installing Minikube dependencies 214 | 215 | sudo apt update 216 | sudo apt install -y curl wget apt-transport-https 217 | 218 | Step-4 : Installing Minikube 219 | 220 | curl -LO https://storage.googleapis.com/minikube/releases/latest/minikube-linux-amd64 221 | sudo install minikube-linux-amd64 /usr/local/bin/minikube 222 | minikube version 223 | 224 | Step-5 : Install Kubectl (Kubernetes Client) 225 | 226 | curl -LO https://storage.googleapis.com/kubernetes-release/release/$(curl -s https://storage.googleapis.com/kubernetes-release/release/stable.txt)/bin/linux/amd64/kubectl 227 | chmod +x kubectl 228 | sudo mv kubectl /usr/local/bin/ 229 | kubectl version -o yaml 230 | 231 | Step-6 : Start MiniKube Server 232 | 233 | minikube start — driver=docker 234 | 235 | Step-7 : Check MiniKube status 236 | 237 | minikube status 238 | 239 | Step-8 : Access K8S Cluster 240 | 241 | kubectl cluster-info 242 | 243 | Step-9 : Access K8S Nodes 244 | 245 | kubectl get nodes 246 | 247 | 248 | $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ Setup Completed $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ 249 | 250 | ##################################### 251 | 🚀 What is a POD in Kubernetes? 252 | ##################################### 253 | 254 | ✅ Key Concepts Explained: 255 | ----------------------------- 256 | 1. If you deploy an app, it will ultimately run inside one or more Pods. It is a building block to run app that we deploy in K8S 257 | 258 | 2. "Applications will be deployed as PODS in k8s." 259 | Your app (e.g., a Spring Boot API) will be containerized using Docker. This container will then be wrapped inside a Pod and deployed on the cluster. 260 | 261 | 3. "To create PODS we will use Docker images." 262 | A Pod runs one or more containers (usually one), and each container uses a Docker image. You can build a Docker image of your app and then deploy it inside a Pod. 263 | 264 | 4. "To create PODS we will use Manifest YML file." 265 | A YAML manifest file defines the configuration for the Pod (or other resources like Deployments). 266 | 267 | It includes: 268 | 269 | a. The name of the Pod 270 | 271 | b. The image to use 272 | 273 | c. Ports to expose 274 | 275 | c. Environment variables, etc. 276 | 277 | 278 | 5. "Create multiple PODS." 279 | The same image (e.g., myapp:latest) can be used to create many Pods. This is how you scale your application—running multiple copies (Pods) to handle more traffic. 280 | 281 | 6. "If we run application with multiple pods then Load Balancing can be performed resulting in 99.9% uptime of the application." 282 | High Availability: If one Pod crashes, others are still running, so your app stays available.Load Balancing: Kubernetes distributes traffic across Pods using a Service (like a load balancer). 283 | 284 | 7. "PODS count will be increased and decreased based on the demand (scalability)." 285 | Kubernetes supports auto-scaling. You can scale Pods manually or automatically using a Horizontal Pod Autoscaler (HPA). Based on CPU/memory usage or custom metrics, Kubernetes will increase/decrease the number of Pods. 286 | 287 | 288 | ############################### 289 | 🚀 Kubernetes Services 290 | ############################### 291 | 292 | -> A Kubernetes Service is used to expose a group of Pods so that they can be accessed reliably. Since Pods can be created and destroyed at any time (with changing IPs), a Service gives them a stable network identity. 293 | 294 | --------------------------- 295 | 🧭 Why Do We Use Services? 296 | --------------------------- 297 | 298 | -> Pods are short-lived and can crash or restart. 299 | 300 | -> Each time a Pod is created, it gets a new IP address. 301 | 302 | -> Directly accessing Pods via IP is not reliable. 303 | 304 | -> A Service gives a static IP to a group of Pods. 305 | 306 | --------------------------------- 307 | 🌐 Types of Kubernetes Services 308 | --------------------------------- 309 | 310 | Kubernetes offers different types of services depending on how and where you want to expose your Pods: 311 | 312 | 🔹 1. ClusterIP (Default) 313 | 🔸 2. NodePort 314 | 🔹 3. LoadBalancer 315 | 316 | ------------------------------------------------------- 317 | 🔐 ClusterIP Service (Internal Access Only) 318 | ------------------------------------------------------- 319 | 320 | 📌 Key Points: 321 | -> Pods are short-lived objects; if one crashes, Kubernetes replaces it with a new Pod. 322 | -> Every new Pod gets a different IP address. 323 | 324 | Note: 🛑 Never rely on Pod IPs to access an application. 325 | 326 | -> A ClusterIP Service groups multiple Pods and assigns them a single static IP. 327 | 328 | -> This static IP allows other components inside the cluster to access the group of Pods reliably, even when individual Pods change. 329 | 330 | --------------------- 331 | 🚫 Access Scope: 332 | --------------------- 333 | 334 | -> Only accessible within the Kubernetes cluster. 335 | 336 | -> Not reachable from the outside world (internet or external clients). 337 | 338 | ---------------- 339 | 💡 Use Case: 340 | ---------------- 341 | -> Internal services such as databases, backend APIs, authentication services, etc. 342 | 343 | Example: You don’t want to expose a database Pod to the internet, so you use a ClusterIP service to allow access only from other internal Pods. 344 | 345 | ---------------------------------------------------- 346 | 🌐 What is a NodePort Service in Kubernetes? 347 | ---------------------------------------------------- 348 | -> A NodePort service is a type of Kubernetes Service that exposes your Pods outside the cluster using a port on each worker node (called a "NodePort"). 349 | 350 | 🧭 Why Use NodePort? 351 | ------------------------------------ 352 | By default, Pods and ClusterIP services are only accessible within the cluster. 353 | 354 | NodePort makes them accessible externally by opening a static port (from 30000 to 32767) on each worker node. 355 | 356 | It allows you to access your application using: 357 | 358 | http://: 359 | 360 | 361 | Note: Here all traffic is routed to one worker node. Means load balancing cannot happen here. 362 | 363 | ----------------------------------------------------- 364 | 🌐 What is a LoadBalancer Service in Kubernetes? 365 | ----------------------------------------------------- 366 | 367 | -> It not only provides external access to your app but also handles automatic traffic distribution across the backend Pods running on different worker nodes. 368 | 369 | 370 | ############################################## 371 | 📄 What is a Kubernetes Manifest YAML? 372 | ############################################## 373 | 374 | -> Think of it as an instruction manual for Kubernetes to create and manage resources. 375 | 376 | 🧱 Main Sections of a Manifest YAML 377 | ----------------------------------- 378 | Here are the 4 main parts: 379 | 380 | apiVersion: # API version to use 381 | kind: # Type of resource (Pod, Service, Deployment, etc.) 382 | metadata: # Metadata like name, labels 383 | spec: # Specification of what the resource should do 384 | 385 | ------------------------------- 386 | 🧪 Example: Pod Manifest YAML 387 | Let’s look at a simple Pod definition: 388 | ------------------------------- 389 | 390 | --- 391 | apiVersion: v1 392 | kind: Pod 393 | metadata: 394 | name: testpod 395 | labels: 396 | app: dempapp 397 | spec: 398 | containers: 399 | - name: test 400 | image: psait/pankajsiracademy:latest 401 | ports: 402 | - containerPort: 9090 403 | ... 404 | 405 | ------------------- 406 | Explanation 407 | ------------------- 408 | 409 | apiVersion: v1 410 | Tells Kubernetes to use version v1 of the API. 411 | 412 | Since you are creating a Pod, this is the correct API version. 413 | 414 | kind: Pod 415 | Defines the type of resource you want to create. 416 | 417 | In this case, it’s a Pod, which is the smallest and simplest unit in Kubernetes. 418 | 419 | metadata: 420 | Metadata gives Kubernetes basic info about your Pod. 421 | 422 | name: testpod 423 | This is the name of your Pod. 424 | 425 | You’ll use this name to check logs or status (e.g., kubectl get pod testpod). 426 | 427 | labels: 428 | Labels are key-value pairs to categorize and group Kubernetes objects. 429 | 430 | app: dempapp is a label to help identify this Pod as part of the "dempapp" application. 431 | 432 | spec: 433 | This section defines what’s inside the Pod. 434 | 435 | containers: 436 | A Pod can contain one or more containers. You're defining one container here. 437 | 438 | - name: test 439 | This is the name of the container inside the Pod (not the Pod itself). 440 | 441 | image: psait/pankajsiracademy:latest 442 | This is the Docker image used to create the container. 443 | 444 | It will pull the latest version of psait/pankajsiracademy from Docker Hub or another registry. 445 | 446 | ⚠️ Make sure the image exists and is accessible (public or with correct credentials). 447 | 448 | ports: 449 | This tells Kubernetes the container is listening on port 8080 inside the Pod. 450 | 451 | containerPort: 8080 452 | This is the internal port your application is running on. 453 | 454 | Kubernetes can use this for things like service routing, health checks, etc. 455 | 456 | ############# 457 | Commands: 458 | ###################### 459 | 460 | Note: Save above content in .yml file 461 | 462 | # execute manifest yml 463 | kubectl apply -f 464 | 465 | # check pods 466 | kubectl get pods 467 | 468 | # check pod logs 469 | kubectl logs 470 | 471 | # Describe pods 472 | kubectl describe pod 473 | 474 | # get pod logs 475 | kubectl logs 476 | 477 | --------------------------------------------- 478 | K8s Service Manifest YAML (for your Pod) 479 | ------------------------------------------ 480 | 481 | --- 482 | apiVersion: v1 483 | kind: Service 484 | metadata: 485 | name: testpod-service 486 | spec: 487 | type: NodePort 488 | selector: 489 | app: dempapp # This must match the Pod's label 490 | ports: 491 | - port: 80 # Exposed port for external access 492 | targetPort: 9090 # Port on which the app is running inside the container 493 | nodePort: 30080 # External port exposed on each node 494 | 495 | 496 | 💡 Explanation: 497 | ---------------------- 498 | name: testpod-service – The name of the service. 499 | 500 | type: NodePort – Exposes the Pod outside the cluster. 501 | 502 | selector.app: dempapp – This matches the label of your Pod, so the service knows which Pod(s) to route to. 503 | 504 | port: 80 – The port used when calling the service.Port 80 is the default port for HTTP traffic 505 | 506 | You're using a web server like Nginx, Apache, or similar. 507 | 508 | targetPort: 8080 – The port your container app actually listens on. 509 | 510 | nodePort: 30080 – External port accessible via http://:30080 511 | 512 | Commands 513 | ___________ 514 | 515 | # 🔍 Check existing services 516 | kubectl get svc 517 | 518 | # 📦 Create the service using the YAML 519 | kubectl apply -f testpod-service.yml 520 | 521 | # 🔁 Verify that the service is created 522 | kubectl get svc 523 | 524 | # 🚪 Open service in browser (Minikube only) 525 | minikube service testpod-service 526 | 527 | # Test 528 | #Get minikube ip address 529 | 530 | Test this in same local network 531 | 532 | curl http://:3080/ 533 | curl http://192.168.49.2:30080/ 534 | 535 | 536 | 537 | Part Meaning 538 | curl A tool to make HTTP requests from the command line. It's often used to test whether a URL is reachable and what it returns. 539 | http://192.168.49.2 This is the IP address of the Minikube VM. It's the entry point into your Kubernetes cluster from your host machine. You found this IP using minikube ip. 540 | :30080 This is the NodePort exposed by your Kubernetes service (testpod-service). It forwards external requests to the internal Pod’s port (8080 in your case). 541 | / This is the path of the URL. Since it's just a /, it hits the root endpoint of your Spring Boot app. 542 | 543 | 544 | ################################################# 545 | note: How to delete pod and services 546 | 547 | kubectl delete pod testpod 548 | kubectl delete svc testpod-service 549 | 550 | kubectl apply -f pod-01.yml 551 | kubectl apply -f service-01.yml 552 | ############################################ 553 | 554 | ############# 555 | Stop complete minikube 556 | ################# 557 | 558 | -> minikube stop 559 | -> minikube delete 560 | -> minikube status 561 | 562 | ##################### 563 | To see all resources running 564 | #################### 565 | 566 | -> kubectl get all 567 | 568 | ######################## 569 | To delete all resources use 570 | ######################## 571 | -> kubectl delete all --all 572 | 573 | 574 | ####################################### 575 | What are name spaces in k8s? 576 | ####################################### 577 | 578 | -> They help logically group and isolate resources. Just like how we create folders to isolate our work in computers. 579 | 580 | ------------------ 581 | Example: 582 | ----------------- 583 | 584 | database-ns = all database-related stuff 585 | 586 | backend-ns = for backend applications 587 | 588 | Note: If we donot specifiy name space they k8S will automatically provide default name - space 589 | 590 | ##################### 591 | Commands 592 | ################### 593 | 594 | list all name spaces 595 | ---------------------- 596 | -> kubectl get ns 597 | 598 | list all pods in given name space 599 | ----------------------------------- 600 | -> kubectl get pod -n 601 | 602 | ############################################# 603 | How to create name space in k8s 604 | ############################################# 605 | 606 | 1. Using kubectl command- 607 | kubectl create namespace backend-ns 608 | 609 | 2.using manifest yml file 610 | 611 | 612 | --- 613 | apiVersion: v1 614 | kind: Namespace 615 | metadata: 616 | name: backend-ns 617 | ... 618 | 619 | # execute manifest yml 620 | kubeclt apply -f 621 | 622 | # get all resources belongs to backend-ns namespace 623 | kubectl get all -n backend-ns 624 | 625 | #get all pods in kube-system 626 | kubectly get pods -n kube-system 627 | 628 | #get all worker nodes 629 | kubectl get nodes 630 | 631 | #delete name space - All resource related to that will be deleted 632 | kubectl delete ns backend-ns 633 | 634 | #Open tunnel 635 | minikube service 636 | 637 | 638 | 639 | ############################ 640 | Namespace with POD with Service creation yml file 641 | ############################## 642 | --- 643 | apiVersion: v1 644 | kind: Namespace 645 | metadata: 646 | name: backend-ns 647 | --- 648 | apiVersion: v1 649 | kind: Pod 650 | metadata: 651 | name: testpod 652 | namespace: backend-ns 653 | labels: 654 | app: dempapp 655 | spec: 656 | containers: 657 | - name: test 658 | image: psait/pankajsiracademy:latest 659 | ports: 660 | - containerPort: 9090 661 | --- 662 | apiVersion: v1 663 | kind: Service 664 | metadata: 665 | name: testpod-service 666 | namespace: backend-ns 667 | spec: 668 | type: NodePort 669 | selector: 670 | app: dempapp # This must match the Pod's label 671 | ports: 672 | - port: 80 # Exposed port for external access 673 | targetPort: 9090 # Port on which the app is running inside the container 674 | nodePort: 30080 # External port exposed on each node 675 | ... 676 | 677 | 678 | ######################################### 679 | k8S Resources 680 | ######################################## 681 | 682 | -> When you create a Pod directly using kind: Pod, Kubernetes does not manage its lifecycle — if it crashes or is deleted, it's gone forever unless recreated manually. 683 | 684 | -> K8S resources manages POD lifecycle 685 | 686 | -> To let Kubernetes manage, restart, and scale Pods, we use higher-level controllers like the ones you listed. 687 | 688 | 🔁 1) ReplicationController (RC) 689 | 🔁 2) ReplicaSet (RS) 690 | 🚀 3) Deployment 691 | 🛰 4) DaemonSet 692 | 💾 5) StatefulSet 693 | 694 | ##################################### 695 | 📦 What is ReplicationController (RC)? 696 | A Kubernetes resource used to manage the lifecycle of Pods. 697 | 698 | Ensures a specified number of Pods are always running. 699 | 700 | Provides self-healing — if a Pod crashes or is deleted, RC will recreate it. 701 | 702 | manifest yml file 703 | 704 | --- 705 | apiVersion: v1 706 | kind: ReplicationController 707 | metadata: 708 | name: webapp 709 | spec: 710 | replicas: 3 711 | selector: 712 | app: dempapp 713 | template: 714 | metadata: 715 | name: testpod 716 | labels: 717 | app: dempapp 718 | spec: 719 | containers: 720 | - name: webappcontainer 721 | image: psait/pankajsiracademy:latest 722 | ports: 723 | - containerPort: 9090 724 | ... 725 | 726 | kubectl apply -f rc.yml 727 | 728 | ######################################################## 729 | 730 | kubectl get all 731 | 732 | kubectl get pods 733 | 734 | kubectl delete pod 735 | 736 | kubectl get pods 737 | 738 | kubectl scale rc dempapp --replicas=5 739 | 740 | kubectl scale rc dempapp --replicas=1 Explain in short 741 | 742 | ############################################## 743 | 744 | ✅ ReplicaSet in Kubernetes 745 | =================== 746 | 🔹 What is a ReplicaSet? 747 | A ReplicaSet (RS) is a Kubernetes resource that ensures a specified number of identical Pods are running at any given time. 748 | 749 | 💡 Key Features: 750 | Self-healing: If a Pod crashes or is manually deleted, the RS will automatically create a new Pod to maintain the desired number. 751 | 752 | Scaling: You can increase or decrease the number of replicas (Pods) easily. 753 | 754 | Selector-based matching: RS manages only those Pods that match its label selector. 755 | 756 | Example: 757 | 758 | # -------- Manually created Pod with label app: myapp -------- 759 | apiVersion: v1 760 | kind: Pod 761 | metadata: 762 | name: myapp-pod 763 | labels: 764 | app: myapp 765 | spec: 766 | containers: 767 | - name: myappcontainer 768 | image: nginx 769 | ports: 770 | - containerPort: 80 771 | 772 | --- 773 | # -------- Manually created Pod with label app: dempapp -------- 774 | apiVersion: v1 775 | kind: Pod 776 | metadata: 777 | name: dempapp-pod 778 | labels: 779 | app: dempapp 780 | spec: 781 | containers: 782 | - name: dempappcontainer 783 | image: nginx 784 | ports: 785 | - containerPort: 80 786 | 787 | --- 788 | # -------- ReplicaSet that manages both app: dempapp and app: myapp -------- 789 | apiVersion: apps/v1 790 | kind: ReplicaSet 791 | metadata: 792 | name: rs-webapp 793 | spec: 794 | replicas: 2 795 | selector: 796 | matchExpressions: 797 | - key: app 798 | operator: In 799 | values: 800 | - dempapp 801 | - myapp 802 | template: 803 | metadata: 804 | labels: 805 | app: dempapp # Pods created by RS will have this label 806 | spec: 807 | containers: 808 | - name: webappcontainer 809 | image: nginx 810 | ports: 811 | - containerPort: 80 812 | ----------------------------------------------------------------------------------------------------- 813 | 814 | 815 | replica-set.yml for practicals 816 | ------------------ 817 | 818 | --- 819 | apiVersion: apps/v1 820 | kind: ReplicaSet 821 | metadata: 822 | name: webapp 823 | spec: 824 | replicas: 3 825 | selector: 826 | matchLabels: 827 | app: dempapp # Must match pod template labels 828 | template: 829 | metadata: 830 | labels: 831 | app: dempapp 832 | spec: 833 | containers: 834 | - name: webappcontainer 835 | image: psait/pankajsiracademy:latest 836 | ports: 837 | - containerPort: 9090 838 | 839 | --- 840 | apiVersion: v1 841 | kind: Service 842 | metadata: 843 | name: webappservice 844 | spec: 845 | type: NodePort 846 | selector: 847 | app: dempapp # Must match pod labels 848 | ports: 849 | - port: 80 850 | targetPort: 9090 851 | nodePort: 30095 852 | ###################################### 853 | ✅ Deployment in Kubernetes 854 | ###################################### 855 | 856 | Feature ReplicaSet Deployment 857 | Manages Pods ✅ Yes ✅ Yes (via ReplicaSet) 858 | Rolling Updates ❌ No ✅ Yes 859 | Rollbacks ❌ No ✅ Yes 860 | YAML Kind ReplicaSet Deployment 861 | Use in Real World Rare Very Common 862 | 863 | A Deployment in Kubernetes is one of the most recommended and used resources for managing Pod lifecycles. It ensures reliable application deployment with features like zero downtime, auto-scaling, rolling updates, and rollback capabilities. 864 | 865 | 🎯 Key Advantages of Using Deployments 866 | Zero Downtime: Deployments ensure high availability by using strategies like rolling updates. Even when pods are being updated, the service remains available to users. 867 | 868 | Auto Scaling: With Kubernetes Horizontal Pod Autoscaler, you can automatically scale your Pods based on CPU or memory usage (or other custom metrics). 869 | 870 | Rolling Update & Rollback: Kubernetes allows rolling updates, which means it will gradually update Pods one by one, ensuring the application remains available throughout the process. If something goes wrong during the update, you can rollback to a previous stable version. 871 | 872 | 👨‍💻 When to Choose Which Strategy? 873 | Use RollingUpdate: 874 | 875 | For most production workloads where high availability and zero downtime are required. 876 | 877 | When you are gradually releasing new versions of your application and want to avoid service disruption. 878 | 879 | Use Recreate: 880 | 881 | For non-critical applications or during maintenance windows where it's okay to have a temporary outage. 882 | 883 | When you need to clear everything and redeploy fresh Pods (e.g., clearing persistent state or major upgrades). 884 | 885 | ############################ 886 | deployment-service.yml 887 | ######################### 888 | --- 889 | apiVersion: apps/v1 890 | kind: Deployment 891 | metadata: 892 | name: webapp 893 | spec: 894 | replicas: 3 895 | selector: 896 | matchLabels: 897 | app: dempapp # Must match pod template labels 898 | template: 899 | metadata: 900 | labels: 901 | app: dempapp 902 | spec: 903 | containers: 904 | - name: webappcontainer 905 | image: psait/pankajsiracademy:latest 906 | ports: 907 | - containerPort: 9090 908 | --- 909 | apiVersion: v1 910 | kind: Service 911 | metadata: 912 | name: webappservice 913 | spec: 914 | type: NodePort 915 | selector: 916 | app: dempapp # Must match pod labels 917 | ports: 918 | - port: 80 919 | targetPort: 9090 920 | nodePort: 30095 921 | 922 | ################################################################################################################# 923 | 924 | 🔧 1. Deployment 925 | 926 | apiVersion: apps/v1 927 | Uses the apps/v1 API to define a Deployment. 928 | 929 | 930 | kind: Deployment 931 | Declares that this is a Deployment (used to manage pods). 932 | 933 | 934 | metadata: 935 | name: webapp 936 | Assigns the Deployment a name: webapp. 937 | 938 | 939 | spec: 940 | replicas: 3 941 | Tells Kubernetes to run 3 replicas (3 pods) of your app. 942 | 943 | selector: 944 | matchLabels: 945 | app: dempapp 946 | The deployment will manage pods that have the label app: dempapp. 947 | 948 | 949 | template: 950 | metadata: 951 | labels: 952 | app: dempapp 953 | This is the pod template. Every pod created will be labeled app: dempapp. 954 | 955 | This must match the selector above. 956 | 957 | spec: 958 | containers: 959 | - name: webappcontainer 960 | image: psait/pankajsiracademy:latest 961 | ports: 962 | - containerPort: 9090 963 | 964 | This is the container spec inside the pod: 965 | 966 | name: webappcontainer 967 | 968 | image: Docker image hosted at Docker Hub (psait/pankajsiracademy:latest) 969 | 970 | containerPort: The app runs on port 9090 inside the container. 971 | 972 | 🌐 2. Service 973 | 974 | apiVersion: v1 975 | Uses the core v1 API to define a Service. 976 | 977 | 978 | kind: Service 979 | Declares a Service (used to expose pods). 980 | 981 | 982 | metadata: 983 | name: webappservice 984 | The service name is webappservice. 985 | 986 | 987 | spec: 988 | type: NodePort 989 | NodePort type: Exposes your app externally by opening a port on every node in the cluster. 990 | 991 | Clients can access it via: 992 | http://:30095 993 | 994 | 995 | selector: 996 | app: dempapp 997 | The service targets pods with label app: dempapp — which matches the Deployment. 998 | 999 | 1000 | ports: 1001 | - port: 80 1002 | targetPort: 9090 1003 | nodePort: 30095 1004 | port: 80: The port the service receives traffic on (internally). 1005 | 1006 | targetPort: 9090: Forwards traffic to container's port 9090. 1007 | 1008 | nodePort: 30095: Opens this port on the Kubernetes node — used to access the service from outside the cluster. 1009 | 1010 | 1011 | ################################ 1012 | Deployment with load balancer 1013 | ############################### 1014 | 1015 | --- 1016 | apiVersion: apps/v1 1017 | kind: Deployment 1018 | metadata: 1019 | name: webapp 1020 | spec: 1021 | replicas: 3 1022 | selector: 1023 | matchLabels: 1024 | app: dempapp # Must match pod template labels 1025 | template: 1026 | metadata: 1027 | labels: 1028 | app: dempapp 1029 | spec: 1030 | containers: 1031 | - name: webappcontainer 1032 | image: psait/pankajsiracademy:latest 1033 | ports: 1034 | - containerPort: 9090 1035 | 1036 | --- 1037 | apiVersion: v1 1038 | kind: Service 1039 | metadata: 1040 | name: webappservice 1041 | spec: 1042 | type: LoadBalancer # ✅ Changed from NodePort to LoadBalancer 1043 | selector: 1044 | app: dempapp 1045 | ports: 1046 | - port: 80 1047 | targetPort: 9090 1048 | 1049 | 1050 | Note: 1051 | 1052 | 🧠 First: Is Each Worker Node a Separate VM? 1053 | ✅ Yes, each worker node in EKS is an individual EC2 instance (VM). 1054 | 1055 | So, if you have 4 worker nodes, EKS will launch 4 separate EC2 instances in your account (under the hood). 1056 | 1057 | 🚀 How to Create More Worker Nodes in EKS? 1058 | There are two ways to create more worker nodes: 1059 | 1060 | ✅ Option 1: CLI Method (Add --nodes flag) 1061 | You can specify the number of nodes when creating the cluster using the --nodes flag: 1062 | 1063 | eksctl create cluster \ 1064 | --name psait-cluster4 \ 1065 | --region ap-south-1 \ 1066 | --node-type t2.medium \ 1067 | --zones ap-south-1a,ap-south-1b \ 1068 | --nodes 4 \ 1069 | --nodes-min 2 \ 1070 | --nodes-max 6 1071 | 🔍 What This Means: 1072 | --nodes 4 → Start with 4 worker nodes 1073 | 1074 | --nodes-min 2 → Minimum nodes for autoscaling 1075 | 1076 | --nodes-max 6 → Maximum nodes for autoscaling 1077 | 1078 | Nodes will be spread across the AZs you mention (load balanced) 1079 | 1080 | ✅ Option 2: YAML Config File (More Flexible) 1081 | Create a cluster.yaml like this: 1082 | 1083 | apiVersion: eksctl.io/v1alpha5 1084 | kind: ClusterConfig 1085 | 1086 | metadata: 1087 | name: psait-cluster4 1088 | region: ap-south-1 1089 | 1090 | availabilityZones: ["ap-south-1a", "ap-south-1b"] 1091 | 1092 | nodeGroups: 1093 | - name: ng-1 1094 | instanceType: t2.medium 1095 | desiredCapacity: 4 1096 | minSize: 2 1097 | maxSize: 6 1098 | volumeSize: 20 1099 | 1100 | Note: We can use terrform for the same to create EKS setup 1101 | 1102 | 1103 | yml file to deploy application in eks with loadbalancer 1104 | ############################################################# 1105 | --- 1106 | apiVersion: apps/v1 1107 | kind: Deployment 1108 | metadata: 1109 | name: webapp 1110 | spec: 1111 | replicas: 2 1112 | strategy: 1113 | type: RollingUpdate 1114 | selector: 1115 | matchLabels: 1116 | app: javawebapp 1117 | template: 1118 | metadata: 1119 | name: javawebpod 1120 | labels: 1121 | app: javawebapp 1122 | spec: 1123 | containers: 1124 | - name: webappcontainer 1125 | image: psait/pankajsiracademy:latest 1126 | ports: 1127 | - containerPort: 9090 1128 | --- 1129 | apiVersion: v1 1130 | kind: Service 1131 | metadata: 1132 | name: websvc 1133 | spec: 1134 | type: LoadBalancer 1135 | selector: 1136 | app: javawebapp 1137 | ports: 1138 | - port: 80 1139 | targetPort: 9090 1140 | ... 1141 | 1142 | pipeline - k8s + maven + docker + jenkins 1143 | --------------------------------------------- 1144 | pipeline { 1145 | agent any 1146 | 1147 | tools{ 1148 | maven "maven-3.9.9" 1149 | } 1150 | 1151 | stages { 1152 | stage('Clone Repo') { 1153 | steps { 1154 | git branch: 'main', url: 'https://github.com/pankajmutha14/docker-test.git' 1155 | } 1156 | } 1157 | stage('Maven Build') { 1158 | steps { 1159 | sh 'mvn clean package' 1160 | } 1161 | } 1162 | stage('Docker Image') { 1163 | steps { 1164 | sh 'docker build -t psait/pankajsiracademy:latest .' 1165 | } 1166 | } 1167 | stage('k8s deployment') { 1168 | steps { 1169 | sh 'kubectl apply -f k8s-deploy.yml' 1170 | } 1171 | } 1172 | } 1173 | } 1174 | 1175 | ############################## 1176 | Scaling in Kubernetes 1177 | ############################# 1178 | 1179 | 1. . HPA - Horizontal Pod Autoscaler 1180 | ########################################### 1181 | What it does: Adds or removes pods based on CPU/memory usage, custom metrics, or external metrics. 1182 | 1183 | Use case: When traffic increases, Kubernetes spins up more pods to handle the load. 1184 | 1185 | Controlled by: The HorizontalPodAutoscaler object. 1186 | 1187 | Example: If CPU usage goes above 80%, HPA can increase the pod count from 2 to 5 automatically 1188 | 1189 | 2. VPA - Vertical Pod Autoscaler 1190 | What it does: Adjusts CPU and memory requests/limits of a pod automatically. 1191 | 1192 | Apply Load in HPA 1193 | -------------- 1194 | kubectl run -i --tty load-generator --rm \ 1195 | --image=busybox --restart=Never \ 1196 | -- /bin/sh -c "while true; do wget -q -O- http://hpa-demo-deployment; sleep 0.01; done" 1197 | 1198 | 1199 | 1200 | kubectl get hpa -w 1201 | 1202 | kubectl describe deploy hpa-demo-deployment 1203 | 1204 | kubectl get hpa 1205 | 1206 | kubectl get events 1207 | 1208 | 1209 | 1210 | ----------------------------------------------------------Further notes will be added soon----------------------------------------------------- 1211 | 1212 | --------------------------------------------------------------------------------