update kubernetes doc

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

@@ -1,64 +1,107 @@
+# 🌐 Kubernetes Pod Management Guide
 
-## Pod Management
+A concise guide for managing Kubernetes Pods using `kubectl` and YAML manifests.
 
-### Listing Pods
+---
 
-- **List Pods in the Default Namespace**
+## 📋 Listing Pods
 
-  ```bash
+### 🔹 Default Namespace
-  kubectl get pods
-  ```
 
-- **List Pods with Detailed Information (Wide Output)**
+List all Pods in the **default** namespace:
 
-  ```bash
+```bash
-  kubectl get pods -o wide
+kubectl get pods
-  ```
+```
 
-- **List Pods in a Specific Namespace**
+### 🔹 Wide Output (More Info)
 
-  ```bash
+List Pods with extended details (e.g., IP, node, etc.):
-  kubectl get pods -o wide -n <namespace-name>
-  ```
 
-### Running a Pod
+```bash
+kubectl get pods -o wide
+```
 
-> **Note:** The `kubectl run` command is best suited for running single pods. For more complex deployments, consider using YAML manifests.
+### 🔹 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
+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 <namepsace> <podname>
+kubectl edit pod -n <namespace> <pod-name>
 ```
-Pod Can not been edit (not editable)
 
+---
+
+## 🔧 Executing into a Pod
+
+Use this to start a shell or run commands inside a container:
 
 ```bash
-kubectl exec -it -n <namespace> <podname> -- <command or shell>
+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
@@ -80,7 +123,7 @@ spec:
 
     - name: ubuntu-c0
       image: ubuntu
-      command: ["/bin/bash","-c","while true; do echo hello-world; sleep 5; done"]
+      command: ["/bin/bash", "-c", "while true; do echo hello-world; sleep 5; done"]
       resources:
         limits:
           memory: "256Mi"

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

@@ -0,0 +1,80 @@
+# 🧩 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/components/4-Deployment.md

@@ -0,0 +1,107 @@
+# 🚀 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 | ❌   | ❌          | ✅          |
+