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