kubernetes doc

Containerization & Orchestration/Kubernetes/workloads/1-NameSpace.md

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+# Kubernetes Namespaces Guide
+
+Kubernetes **namespaces** allow you to organize and isolate resources within your cluster.
+
+---
+
+## 🧾 Listing Namespaces
+
+To list all namespaces:
+
+```bash
+kubectl get namespaces
+```
+
+or the shorthand:
+
+```bash
+kubectl get ns
+```
+
+---
+
+## 🛠️ Creating a Namespace
+
+Create a new namespace:
+
+```bash
+kubectl create namespace <namespace-name>
+```
+
+or:
+
+```bash
+kubectl create ns <namespace-name>
+```
+
+---
+
+## 🗑️ Deleting a Namespace
+
+Delete a namespace:
+
+```bash
+kubectl delete ns <namespace-name>
+```
+
+---
+
+## ⚠️ Best Practices & Notes
+
+* **Namespaces are isolated**, but they **can still communicate** with each other by default.
+* It is **not recommended to create namespaces that start with `kube-`**, as those are typically reserved for system components.
+
+---
+
+## 📄 Creating a Namespace with a Manifest
+
+You can define a namespace using a YAML manifest:
+
+```yaml
+apiVersion: v1
+kind: Namespace
+metadata:
+  name: namespace-test
+```
+
+Apply it using:
+
+```bash
+kubectl apply -f namespace.yaml
+```
+

Containerization & Orchestration/Kubernetes/workloads/10-Deployment-With-Services.md

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+### **1st Document: Namespace**
+
+```yaml
+apiVersion: v1
+```
+
+* Specifies the API version used. Here, it's version 1 of the core Kubernetes API.
+
+```yaml
+kind: Namespace
+```
+
+* Declares the resource type. This is a **Namespace**, which logically isolates groups of resources.
+
+```yaml
+metadata:
+  name: ns
+```
+
+* Metadata block.
+
+  * `name: ns` sets the name of the namespace to `ns`.
+
+---
+
+### **2nd Document: Service**
+
+```yaml
+---
+```
+
+* Separates multiple documents in the YAML file.
+
+```yaml
+apiVersion: v1
+```
+
+* Uses the core v1 API again.
+
+```yaml
+kind: Service
+```
+
+* Declares a **Service** resource, which provides stable networking to access pods.
+
+```yaml
+metadata:
+  name: nginx-service
+  namespace: ns
+  labels:
+    app: nginx
+```
+
+* Metadata block:
+
+  * `name: nginx-service`: name of the Service.
+  * `namespace: ns`: places this service in the previously created `ns` namespace.
+  * `labels`: key-value pairs used for organizing and selecting resources. Here, `app: nginx`.
+
+```yaml
+spec:
+  type: ClusterIP
+```
+
+* `spec` describes the behavior.
+
+  * `type: ClusterIP`: exposes the service internally within the cluster using a virtual IP.
+
+```yaml
+  selector:
+    app: nginx
+```
+
+* This selects pods with the label `app: nginx` to receive traffic from this service.
+
+```yaml
+  ports:
+    - name: http
+      port: 80
+      targetPort: 8080
+```
+
+* Defines port configuration:
+
+  * `name: http`: a name for the port (optional but useful for readability).
+  * `port: 80`: the port that the service exposes internally.
+  * `targetPort: 8080`: the port on the pod that receives the traffic.
+
+---
+
+### **3rd Document: Deployment**
+
+```yaml
+---
+```
+
+* Separates from the previous document.
+
+```yaml
+apiVersion: apps/v1
+```
+
+* Uses the `apps/v1` API group, suitable for deployments and other controllers.
+
+```yaml
+kind: Deployment
+```
+
+* Declares a **Deployment**, which ensures a specified number of pod replicas are running.
+
+```yaml
+metadata:
+  name: nginx-deployment
+  namespace: ns
+  labels:
+    app: nginx
+```
+
+* Metadata block:
+
+  * `name: nginx-deployment`: name of the deployment.
+  * `namespace: ns`: places this in the `ns` namespace.
+  * `labels: app: nginx`: used for matching with selectors.
+
+```yaml
+spec:
+  replicas: 2
+```
+
+* Desired number of pod replicas to run: 2.
+
+```yaml
+  selector:
+    matchLabels:
+      app: nginx
+```
+
+* Tells the deployment which pods to manage, by matching labels (`app: nginx`).
+
+```yaml
+  template:
+    metadata:
+      labels:
+        app: nginx
+```
+
+* Template for creating new pods:
+
+  * Each pod created will have `app: nginx` label.
+
+```yaml
+    spec:
+      containers:
+        - name: nginx
+          image: nginx:latest
+```
+
+* Pod spec:
+
+  * One container named `nginx`, using the latest official Nginx image.
+
+```yaml
+          ports:
+            - containerPort: 8080
+```
+
+* The container exposes port 8080 (must match the `targetPort` in the Service).
+
+```yaml
+          resources:
+            requests:
+              cpu: "100m"
+              memory: "128Mi"
+            limits:
+              cpu: "250m"
+              memory: "256Mi"
+```
+
+* **Resource management**:
+
+  * `requests`: the minimum guaranteed resources.
+
+    * `cpu: 100m` = 0.1 CPU core.
+    * `memory: 128Mi` = 128 MiB RAM.
+  * `limits`: the maximum resources the container can use.
+
+    * `cpu: 250m` = 0.25 CPU core.
+    * `memory: 256Mi` = 256 MiB RAM.
+

Containerization & Orchestration/Kubernetes/workloads/2-Pod.md

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+# 🌐 Kubernetes Pod Management Guide
+
+A concise guide for managing Kubernetes Pods using `kubectl` and YAML manifests.
+
+---
+
+## 📋 Listing Pods
+
+### 🔹 Default Namespace
+
+List all Pods in the **default** namespace:
+
+```bash
+kubectl get pods
+```
+
+### 🔹 Wide Output (More Info)
+
+List Pods with extended details (e.g., IP, node, etc.):
+
+```bash
+kubectl get pods -o wide
+```
+
+### 🔹 Specific Namespace
+
+List Pods in a specific namespace:
+
+```bash
+kubectl get pods -o wide -n <namespace-name>
+```
+
+---
+
+## 🚀 Running a Pod
+
+> **Note:** `kubectl run` is ideal for quick tests or running **single** Pods. For production workloads, use **YAML manifests** or **Deployments**.
+
+### 🔹 Run a Pod in Default Namespace
+
+```bash
+kubectl run <pod-name> --image=<image-name>
+```
+
+### 🔹 Run a Pod in a Specific Namespace
+
+```bash
+kubectl run <pod-name> --image=<image-name> -n <namespace>
+```
+
+---
+
+## ❌ Deleting Pods
+
+### 🔹 Standard Delete
+
+```bash
+kubectl delete pod <pod-name> -n <namespace-name>
+```
+
+### 🔹 Force Delete
+
+```bash
+kubectl delete pod <pod-name> -n <namespace-name> --force
+```
+
+### 🔹 Immediate Force Delete (No Grace Period)
+
+```bash
+kubectl delete pod <pod-name> -n <namespace-name> --force --grace-period=0
+```
+
+---
+
+## ✏️ Editing a Pod
+
+> **Warning:** Pods are **not directly editable**. Attempting to edit a running pod will result in a temporary patch but not persistent changes.
+
+```bash
+kubectl edit pod -n <namespace> <pod-name>
+```
+
+---
+
+## 🔧 Executing into a Pod
+
+Use this to start a shell or run commands inside a container:
+
+```bash
+kubectl exec -it -n <namespace> <pod-name> -- <command>
+```
+
+Example for a shell:
+
+```bash
+kubectl exec -it -n dev my-pod -- /bin/bash
+```
+
+---
+
+## 🧾 Example Pod YAML Manifest
+
+A multi-container Pod with resource limits and node selector:
+
+```yaml
+apiVersion: v1
+kind: Pod
+metadata:
+  namespace: dev
+  name: pod-1
+  labels:
+    label1: test
+    label2: test2
+    app.kubernetes.io/label3: test3
+    app.kubernetes.io/label4: test4
+spec:
+  containers:
+    - name: nginx-server
+      image: nginx
+
+    - name: nginx-exporter
+      image: nginx-exporter
+
+    - name: ubuntu-c0
+      image: ubuntu
+      command: ["/bin/bash", "-c", "while true; do echo hello-world; sleep 5; done"]
+      resources:
+        limits:
+          memory: "256Mi"
+          cpu: "250m"
+        requests:
+          memory: "128Mi"
+          cpu: "125m"
+  nodeSelector:
+    hostname: k3s
+    app.kubernetes.io/disk: ssd
+```
+

Containerization & Orchestration/Kubernetes/workloads/3-Replicaset.md

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+# 🧩 Kubernetes ReplicaSet Management
+
+A guide to working with **ReplicaSets** in Kubernetes, including inspection, editing behavior, and configuration examples.
+
+---
+
+## 📦 Listing Pods and ReplicaSets
+
+### 🔹 List Pods in a Namespace
+
+```bash
+kubectl get pod -n <namespace>
+```
+
+### 🔹 List ReplicaSets in a Namespace
+
+```bash
+kubectl get rs -n <namespace>
+```
+
+---
+
+## ✏️ Editing a ReplicaSet
+
+You can attempt to edit a ReplicaSet:
+
+```bash
+kubectl edit rs -n <namespace> <replica-set-name>
+```
+
+> ⚠️ **Note:**
+> Editing the **image** in a ReplicaSet directly will not automatically update existing Pods.
+> This is because ReplicaSets do not perform **rolling updates**.
+> Pods will only use the new image **after the old ones are deleted and new ones are created**.
+
+**To apply image changes effectively:**
+
+1. **Delete existing Pods** manually:
+
+   ```bash
+   kubectl delete pod -l <label-selector> -n <namespace>
+   ```
+
+2. **Or**, use a higher-level controller like a **Deployment** for image updates and rolling behavior.
+
+---
+
+## 🧾 Example ReplicaSet YAML
+
+Below is a minimal and clear ReplicaSet configuration:
+
+```yaml
+apiVersion: apps/v1
+kind: ReplicaSet
+metadata:
+  name: app-1
+  namespace: dev
+  labels:
+    label1: test1
+    app.kubernetes.io/label2: test2
+spec:
+  replicas: 3
+  selector:
+    matchLabels:
+      app.kubernetes.io/label2: test2
+  template:
+    metadata:
+      labels:
+        app.kubernetes.io/label2: test2
+        os: linux
+    spec:
+      containers:
+        - name: nginx
+          image: nginx
+```
+
+> ✅ **Tip:**
+> Ensure that the `template.metadata.labels` **matches exactly** with `spec.selector.matchLabels`.
+> This is critical for proper ReplicaSet Pod matching.
+

Containerization & Orchestration/Kubernetes/workloads/4-Deployment.md

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+# 🚀 Kubernetes Deployment Management
+
+A guide to managing **Deployments** in Kubernetes, including listing, editing, scaling, rollbacks, and version history.
+
+---
+
+## 📋 Listing & Editing Deployments
+
+### 🔹 List Deployments in a Namespace
+
+```bash
+kubectl get deploy -n <namespace>
+```
+
+### 🔹 Edit a Deployment
+
+```bash
+kubectl edit deployment.apps -n <namespace> <deployment-name>
+```
+
+> 🛠️ **Note:**
+> Unlike ReplicaSets, Deployments **automatically update** existing Pods when the image or spec is changed. This makes Deployments ideal for rolling updates and version control.
+
+---
+
+## 📈 Scaling a Deployment
+
+Scale the number of replicas (Pods) for a Deployment:
+
+```bash
+kubectl scale -n <namespace> deployment <deployment-name> --replicas=<number>
+```
+
+---
+
+## 🔁 Rollout Management
+
+### 🔹 View Rollout History
+
+```bash
+kubectl rollout history deployment -n <namespace> <deployment-name>
+```
+
+### 🔹 View Specific Revision
+
+```bash
+kubectl rollout history deployment -n <namespace> <deployment-name> --revision=<revision-number>
+```
+
+### 🔹 Roll Back to a Previous Revision
+
+```bash
+kubectl rollout undo deployment -n <namespace> <deployment-name> --to-revision=<revision-number>
+```
+
+> ✅ **Tip:**
+> Deployments maintain revision history. This allows you to **roll back to a previous working version** in case of failure.
+
+---
+
+## 🧾 Example Deployment YAML
+
+```yaml
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: app-1
+  namespace: dev
+  labels:
+    label1: test1
+    app.kubernetes.io/label2: test2
+spec:
+  replicas: 3
+  selector:
+    matchLabels:
+      app.kubernetes.io/label2: test2
+  template:
+    metadata:
+      labels:
+        app.kubernetes.io/label2: test2
+        os: linux
+    spec:
+      containers:
+        - name: nginx
+          image: nginx
+```
+
+> 🎯 **Why use Deployments?**
+> They offer:
+
+* Rolling updates
+* Rollbacks
+* Declarative Pod management
+* History tracking
+
+---
+
+## ✅ Summary
+
+| Feature          | Pod | ReplicaSet | Deployment |
+| ---------------- | --- | ---------- | ---------- |
+| Manual creation  | ✅   | 🚫         | 🚫         |
+| Scales Pods      | ❌   | ✅          | ✅          |
+| Self-healing     | ❌   | ✅          | ✅          |
+| Rolling updates  | ❌   | ❌          | ✅          |
+| Revision history | ❌   | ❌          | ✅          |
+

Containerization & Orchestration/Kubernetes/workloads/5-hpa.md

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+# 📈 Horizontal Pod Autoscaler (HPA)
+
+The Horizontal Pod Autoscaler automatically scales the number of pods in a deployment based on observed CPU utilization (or other select metrics).
+
+---
+
+## ⚙️ Basic Commands
+
+### 🚀 Create an HPA
+Create an HPA for a deployment, scaling based on CPU usage:
+
+```bash
+kubectl -n <namespace> autoscale deployment <deployment-name> --cpu-percent=20 --min=4 --max=10
+````
+
+### 📊 View Existing HPAs
+
+List all HPAs in a specific namespace:
+
+```bash
+kubectl get hpa -n <namespace>
+```
+
+### ❌ Delete an HPA
+
+Remove a Horizontal Pod Autoscaler:
+
+```bash
+kubectl delete hpa -n <namespace> <hpa-name>
+```
+
+### 🛠️ Edit an HPA
+
+Manually edit an existing HPA configuration:
+
+```bash
+kubectl edit hpa -n <namespace> <hpa-name>
+```
+
+---
+
+## 🧾 Example HPA Manifest
+
+You can define an HPA using a YAML file for more control:
+
+```yaml
+apiVersion: autoscaling/v2
+kind: HorizontalPodAutoscaler
+metadata:
+  name: hpa-test
+  namespace: dev
+spec:
+  minReplicas: 1
+  maxReplicas: 10
+  metrics:
+  - type: Resource
+    resource:
+      name: cpu
+      target:
+        type: Utilization
+        averageUtilization: 50
+```
+
+> ℹ️ **Note:** The above manifest uses API version `autoscaling/v2` for enhanced metric support.
+
+---
+

Containerization & Orchestration/Kubernetes/workloads/6-DaemonSet.md

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+# 🧩 DaemonSet in Kubernetes
+
+A **DaemonSet** ensures that a copy of a specific pod runs on **every (or some) node** in the cluster. It’s typically used for background system-level services like log collection, monitoring, or networking tools.
+
+---
+
+## 📌 Key Characteristics
+
+- Automatically deploys one pod per worker node.
+- Ensures the pod stays on each node as long as the DaemonSet exists.
+- Automatically adds pods to new nodes when they join the cluster.
+
+---
+
+## 📄 Example DaemonSet YAML
+
+Below is a simple DaemonSet example that deploys `nginx` to every node in the `web` namespace:
+
+```yaml
+apiVersion: apps/v1
+kind: DaemonSet
+metadata:
+  name: nginx
+  namespace: web
+  labels:
+    app: web-servers
+spec:
+  selector:
+    matchLabels:
+      app: web-servers
+  template:
+    metadata:
+      labels:
+        app: web-servers
+    spec:
+      containers:
+        - name: nginx
+          image: nginx:1.27
+````
+

Containerization & Orchestration/Kubernetes/workloads/7-Jobs.md

@@ -0,0 +1,48 @@
+# ⏳ Kubernetes Jobs
+
+A **Job** in Kubernetes runs a pod to completion. It ensures that a specified number of pods successfully terminate.
+
+Use Jobs for **batch processing**, **one-off tasks**, or **short-lived workloads**.
+
+---
+
+## 🔍 Job Commands
+
+### 📄 List Jobs in a Namespace
+```bash
+kubectl get jobs.batch -n <namespace>
+````
+
+### ❌ Delete a Job
+
+```bash
+kubectl delete jobs.batch -n <namespace> <job-name>
+```
+
+---
+
+## 🧾 Example Job Manifest
+
+Here’s a minimal example of a Job that runs a simple `echo` command:
+
+```yaml
+apiVersion: batch/v1
+kind: Job
+metadata:
+  name: myjob
+  namespace: ns
+spec:
+  template:
+    spec:
+      containers:
+        - name: job1
+          image: alpine
+          command:
+            - echo 
+            - "hello world"
+      restartPolicy: Never
+```
+
+> 💡 **Note:** Always set `restartPolicy` to `Never` or `OnFailure` for jobs.
+> 📌 Jobs are useful for tasks like backups, report generation, or database migrations.
+

Containerization & Orchestration/Kubernetes/workloads/8-Cronjobs.md

@@ -0,0 +1,51 @@
+# ⏰ Kubernetes CronJobs
+
+A **CronJob** in Kubernetes allows you to run jobs on a recurring schedule, similar to traditional UNIX `cron` jobs. Ideal for periodic tasks like backups, reports, or scheduled notifications.
+
+---
+
+## 🔍 CronJob Commands
+
+### 📄 List CronJobs in a Namespace
+```bash
+kubectl get cronjobs.batch -n <namespace>
+````
+
+### ❌ Delete a CronJob
+
+```bash
+kubectl delete cronjobs.batch -n <namespace> <cronjob-name>
+```
+
+---
+
+## 🧾 Example CronJob Manifest
+
+This CronJob runs every minute and prints the date followed by "Kubernetes":
+
+```yaml
+apiVersion: batch/v1
+kind: CronJob
+metadata:
+  name: cronjob1
+  namespace: ns
+spec:
+  schedule: "* * * * *"
+  jobTemplate:
+    spec:
+      template:
+        spec:
+          containers:
+            - name: cronjob
+              image: debian:bookworm
+              command:
+                - /bin/bash
+                - -c
+                - date; echo Kubernetes
+          restartPolicy: Never
+```
+
+> 🛠 **Fix:** Changed `JobTemplate` to `jobTemplate` (YAML keys are case-sensitive).
+> 🕐 The `schedule` field follows standard cron format: `minute hour day-of-month month day-of-week`.
+> 🧠 **Tip:** Always test cron timing carefully to avoid unintentional frequent runs.
+

Containerization & Orchestration/Kubernetes/workloads/9-Services.md

@@ -0,0 +1,73 @@
+# 🔗 Services in Kubernetes (SVC)
+
+A **Service** in Kubernetes provides a stable networking interface to access a set of pods. It allows for decoupling between client applications and the underlying pods by using DNS names and selectors.
+
+---
+
+## 🌐 Service Basics
+
+### 📌 Service Flow
+```
+
+Service ➡️ Endpoint ➡️ Pods
+
+````
+
+- Services abstract access to a group of pods.
+- Services automatically get a DNS name in the cluster.
+- They use selectors to route traffic to matching pods.
+
+---
+
+## 🧭 Service Types
+
+1. **ClusterIP** (default)  
+   - Accessible only within the cluster.
+
+2. **NodePort**  
+   - Exposes the service on a static port on each node.
+
+3. **LoadBalancer**  
+   - Provisions an external IP via a cloud provider to expose the service.
+
+---
+
+## 🧪 Useful Commands
+
+### 🔍 Get Endpoints
+```bash
+kubectl get ep -n <namespace>
+````
+
+### 📄 Get Services
+
+```bash
+kubectl get svc -n <namespace>
+```
+
+---
+
+## 🧾 Example Service Manifest
+
+```yaml
+apiVersion: v1
+kind: Service
+metadata:
+  name: nginx
+  namespace: ns
+  labels:
+    app: web-server
+spec:
+  type: ClusterIP  # Options: ClusterIP, NodePort, LoadBalancer
+  selector:
+    app: nginx
+  ports:
+    - name: http  # Port name is optional but useful
+      port: 80  # Service port
+      targetPort: 8080  # Container port
+```
+
+> 🔍 **Note:** The `selector` must match pod labels for the service to route traffic correctly.
+> 🧠 **Tip:** Use `kubectl describe svc <svc-name>` to troubleshoot or verify service-to-pod connectivity.
+> 🌐 Services are resolved by DNS using the format: `<service-name>.<namespace>.svc.cluster.local`.
+

Containerization & Orchestration/Kubernetes/workloads/all.md

@@ -1,208 +0,0 @@
-# Kubernetes YAML Files
-
-This document provides explanations and details for various Kubernetes YAML configurations, describing how different Kubernetes objects such as Namespaces, Pods, and other specifications are defined and utilized. The examples cover creating namespaces, deploying pods, setting resource limits, and using node selectors.
-
-## Namespace Definition
-
-```yaml
-apiVersion: v1
-kind: Namespace
-metadata:
-  name: my-ns
-```
-
-- **apiVersion**: Specifies the version of the Kubernetes API.
-- **kind**: Defines the type of Kubernetes object, here it's a `Namespace`.
-- **metadata**: Contains data that helps uniquely identify the object, including a `name`.
-
-This YAML file creates a namespace named `my-ns` which isolates a group of resources within Kubernetes.
-
-## Pod Definitions
-
-### Nginx Pod
-
-```yaml
-apiVersion: v1
-kind: Pod
-metadata:
-  namespace: my-ns
-  name: nginx-pod
-  labels:
-    app: app1
-    zone: staging
-    version: v1.0.1
-    app.kubernetes.io/product: nginx-pod
-spec:
-  containers:
-    - name: naginx-container
-      image: nginx:latest
-      ports:
-        - containerPort: 80
-```
-
-- **metadata.namespace**: Specifies the namespace the pod belongs to (`my-ns`).
-- **metadata.name**: The name of the pod (`nginx-pod`).
-- **metadata.labels**: Key-value pairs for organizing and selecting resources.
-- **spec.containers**: Specifies the containers within the pod. Each container has:
-  - **name**: Container name.
-  - **image**: The Docker image to run (`nginx:latest`).
-  - **ports**: List of ports to expose from the container (`containerPort: 80`).
-
-This file defines a pod named `nginx-pod` running the latest Nginx container in the `my-ns` namespace.
-
-### Test Pod 1
-
-```yaml
-apiVersion: v1
-kind: Pod
-metadata:
-  namespace: my-ns
-  name: testpod1
-spec:
-  containers:
-    - name: c00
-      image: ubuntu
-      command: ["/bin/bash", "-c", "while true; do echo Hello-Coder; sleep 5 ; done"]
-    - name: c01
-      image: ubuntu
-      command: ["/bin/bash", "-c", "while true; do echo Hello-Programmer; sleep 5 ; done"]
-```
-
-- **spec.containers.command**: Overrides the default command for the container, in this case, running a looped bash script that prints a message every 5 seconds.
-
-This defines a pod named `testpod1` with two Ubuntu containers in the `my-ns` namespace, each running a different command.
-
-## Pod with Resource Requests and Limits
-
-```yaml
-apiVersion: v1
-kind: Pod
-metadata:
-  namespace: my-ns
-  name: testpod1
-spec:
-  containers:
-    - name: c00
-      image: ubuntu
-      command:
-        - /bin/bash
-        - -c
-        - while true; do echo Hello-Coder; sleep 5 ; done
-    - name: c01
-      image: ubuntu
-      command:
-        - /bin/bash
-        - -c
-        - while true; do echo Hello-Programmer; sleep 5 ; done
-      resources:
-        limits:
-          memory: "128Mi"
-          cpu: "500m"
-        requests:
-          memory: "64Mi"
-          cpu: "250m"
-```
-
-- **resources.limits**: Specifies the maximum amount of resources a container can use.
-- **resources.requests**: Specifies the amount of resources a container is guaranteed.
-
-This pod configuration defines resource limits and requests for the containers to ensure they do not exceed specific memory and CPU usage.
-
-## Pod with NodeSelector
-
-```yaml
-apiVersion: v1
-kind: Pod
-metadata:
-  namespace: my-ns
-  name: testpod3
-spec:
-  containers:
-    - name: c00
-      image: ubuntu
-      command:
-        - /bin/bash
-        - -c
-        - while true; do echo Hello-Coder; sleep 5 ; done
-    - name: c01
-      image: ubuntu
-      command:
-        - /bin/bash
-        - -c
-        - while true; do echo Hello-Programmer; sleep 5 ; done
-      resources:
-        limits:
-          memory: "128Mi"
-          cpu: "500m"
-        requests:
-          memory: "64Mi"
-          cpu: "250m"
-  nodeSelector:
-    kubernetes.io/hostname: k8s2
-    kubernetes.io/disk: ssd
-```
-
-- **nodeSelector**: Ensures the pod is scheduled on nodes with the specified labels (`kubernetes.io/hostname: k8s2` and `kubernetes.io/disk: ssd`).
-
-This configuration places the pod on specific nodes that match the given labels.
-
-## Simple Pod Templates
-
-### Basic Pod
-
-```yaml
-apiVersion: v1
-kind: Pod
-metadata:
-  name: myapp
-  labels:
-    name: myapp
-spec:
-  containers:
-  - name: myapp
-    image: <Image>
-    resources:
-      limits:
-        memory: "128Mi"
-        cpu: "500m"
-    ports:
-      - containerPort: <Port>
-```
-
-This is a template for a basic pod named `myapp` with configurable image and port settings.
-
-### Nginx Pod
-
-```yaml
-apiVersion: v1
-kind: Pod
-metadata:
-  name: my-pod
-  labels:
-    app: MyApp
-spec:
-  containers:
-  - name: my-container
-    image: nginx:latest
-    ports:
-    - containerPort: 80
-```
-
-This defines a pod named `my-pod` running an Nginx container exposing port 80.
-
-## Useful Kubernetes Commands
-
-### View Pod Details
-
-```bash
-kubectl get pod -n my-ns <pod-name> -o yaml
-```
-
-This command retrieves and displays the YAML configuration of the pod `testpod1` in the namespace `my-ns`.
-
-### Label a Node
-
-```bash
-kubectl label node <node-name> kubernetes.io/<var-name>=<var-value>
-kubectl get nodes --show-labels
-```

Containerization & Orchestration/Kubernetes/workloads/deployment-with-service.yaml

@@ -1,23 +0,0 @@
-apiVersion: apps/v1
-kind: Deployment
-metadata:
-  name: app-deployment
-  namespace: ns-test
-  labels:
-    name: deployment-test
-    app: nginx
-spec:
-  replicas: 2
-  selector:
-    matchLabels:
-      name: app1
-      app: nginx
-  template:
-    metadata:
-      labels:
-        name: app1
-        app: nginx
-    spec:
-      containers:
-        - name: nginx-deployment
-          image: nginx:1.26

Containerization & Orchestration/Kubernetes/workloads/manifests/deployment-with-service.yaml

@@ -0,0 +1,52 @@
+apiVersion: v1
+kind: Namespace
+metadata:
+  name: ns
+
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: nginx-service
+  namespace: ns
+  labels:
+    app: nginx
+spec:
+  type: ClusterIP
+  selector:
+    app: nginx
+  ports:
+    - name: http
+      port: 80
+      targetPort: 8080
+
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: nginx-deployment
+  namespace: ns
+  labels:
+    app: nginx
+spec:
+  replicas: 2
+  selector:
+    matchLabels:
+      app: nginx
+  template:
+    metadata:
+      labels:
+        app: nginx
+    spec:
+      containers:
+        - name: nginx
+          image: nginx:latest
+          ports:
+            - containerPort: 8080
+          resources:
+            requests:
+              cpu: "100m"
+              memory: "128Mi"
+            limits:
+              cpu: "250m"
+              memory: "256Mi"