kuber doc: configmap

Containerization & Orchestration/Kubernetes/Commands/3-Commands.md

@@ -115,3 +115,7 @@ This guide provides a concise reference for common `kubectl` commands used to ma
   Any YAML files placed in `/etc/kubernetes/manifests/` are automatically loaded when the kubelet starts (for example, after a server reboot).
 
 
+
+```bash
+kubectl cp -n <ns> <pod-name>:dir/ ./
+```

Containerization & Orchestration/Kubernetes/Commands/config-map.md

@@ -0,0 +1,104 @@
+# 🧾 Kubernetes ConfigMap
+
+## 📘 What is a ConfigMap?
+
+A **ConfigMap** allows you to **store configuration data** in key-value pairs that can be:
+
+* Mounted as files in a Pod
+* Exposed as environment variables
+* Consumed by Kubernetes workloads without hardcoding settings in container images
+
+---
+
+## ⚙️ Creating a ConfigMap from Files
+
+Create a ConfigMap from one or more files:
+
+```bash
+kubectl -n <namespace> create configmap <configmap-name> --from-file=<file-or-directory>
+```
+
+### ✅ Examples
+
+```bash
+# Create from a single file
+kubectl -n <ns> create configmap nginx-conf --from-file=./nginx.conf
+
+# Create from multiple files
+kubectl -n <ns> create configmap nginx-conf --from-file=./nginx.conf --from-file=./site.conf
+```
+
+---
+
+## 📂 Viewing and Editing ConfigMaps
+
+```bash
+# List ConfigMaps in a namespace
+kubectl get cm -n <namespace>
+
+# Edit a ConfigMap
+kubectl -n <namespace> edit configmap <configmap-name>
+```
+
+---
+
+## 📄 ConfigMap YAML Example
+
+```yaml
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: game-demo
+data:
+  # Key-value style
+  player_initial_lives: "3"
+  ui_properties_file_name: "user-interface.properties"
+
+  # Multi-line file-style entries
+  game.properties: |
+    enemy.types=aliens,monsters
+    player.maximum-lives=5    
+  user-interface.properties: |
+    color.good=purple
+    color.bad=yellow
+    allow.textmode=true    
+```
+
+---
+
+## 🚀 Deployment Example: Using ConfigMap as Volume
+
+```yaml
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: app-1
+  namespace: dev
+  labels:
+    app.kubernetes.io/name: nginx
+spec:
+  replicas: 3
+  selector:
+    matchLabels:
+      app.kubernetes.io/name: nginx
+  template:
+    metadata:
+      labels:
+        app.kubernetes.io/name: nginx
+        os: linux
+    spec:
+      containers:
+        - name: nginx
+          image: nginx
+          ports:
+            - containerPort: 80
+          volumeMounts:
+            - name: configfile
+              mountPath: /etc/nginx/nginx.conf
+              subPath: nginx.conf  # Mount specific file from ConfigMap
+      volumes:
+        - name: configfile
+          configMap:
+            name: nginx-conf
+```
+