Add migration overview from multi-container Web Apps to AKS

0_Azure/8_AzureApps/demos/1_fromMulti-containerWebApp_toAKS.md

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+# Migrating from <br/> Multi-container Web Apps to AKS - Overview 
+
+Costa Rica
+
+[![GitHub](https://badgen.net/badge/icon/github?icon=github&label)](https://github.com)
+[![GitHub](https://img.shields.io/badge/--181717?logo=github&logoColor=ffffff)](https://github.com/)
+[brown9804](https://github.com/brown9804)
+
+Last updated: 2025-10-23
+
+----------
+
+<details>
+<summary><b>List of References</b> (Click to expand)</summary>
+
+- [Choose an Azure compute service (Decision Tree)](https://learn.microsoft.com/en-us/azure/architecture/guide/technology-choices/compute-decision-tree)
+- [Free, Standard, and Premium pricing tiers for Azure Kubernetes Service (AKS)](https://learn.microsoft.com/en-us/azure/aks/free-standard-pricing-tiers)
+- [AKS long-term support](https://learn.microsoft.com/en-us/azure/aks/long-term-support)
+- [AKS pricing details](https://azure.microsoft.com/en-us/pricing/details/kubernetes-service/)
+- [Azure Pricing Calculator](https://azure.microsoft.com/en-us/pricing/calculator/)
+- [Azure managed disk types](https://learn.microsoft.com/en-us/azure/virtual-machines/disks-types)
+- [Disk type comparison](https://learn.microsoft.com/en-us/azure/virtual-machines/disks-types#disk-type-comparison)
+- [Microsoft Sales and Support](https://support.microsoft.com/contactus?ContactUsExperienceEntryPointAssetId=S.HP.SMC-HOME)
+- [Microsoft Copilot in Azure (VM sizing demo video)](https://www.youtube.com/watch?v=HGdhUFHnij4&t=819s)
+
+</details>
+
+<details>
+<summary><b>Table of Content</b> (Click to expand)</summary>
+
+- [Overview](#overview)
+- [Container related services](#container-related-services)
+- [How to choose?](#how-to-choose)
+- [Pricing example](#pricing-example)
+- [Best practices](#best-practices)
+
+</details>
+
+> [!NOTE]
+> If you have any questions or need further clarification, please reach out to your Microsoft account team or contact Microsoft directly: [Microsoft Sales and Support](https://support.microsoft.com/contactus?ContactUsExperienceEntryPointAssetId=S.HP.SMC-HOME) for additional support and guidance, or
+
+| Component | Role | 
+| --- | --- | 
+| Containers | Lightweight, `portable units that package code, dependencies, and runtime together`. | 
+| Docker | Tool that `builds and runs these containers locally`. It lets you define`multi-container setups using docker-compose.` |
+| Docker Compose | Manages multiple containers on one host |
+| Kubernetes (K8s) | Orchestrates containers across many hosts (nodes) | 
+| AKS | Azure’s managed Kubernetes `handles infrastructure, scaling, and updates for you` | 
+
+## Overview 
+
+`Monolithic → Microservices → Containerization → Orchestration` This progression improves scalability, resilience, and agility for modern cloud-native applications.
+
+<div align="center">
+  <img width="778" height="369" alt="image" src="https://github.com/user-attachments/assets/23f6e6e9-1c37-47f5-afae-e5fcdf847d93" />
+</div>
+
+> - `Monolithic Application`: A single, large application that contains all components (Recruitment Website, Job Application, Job Vacancies, Recruiters, etc) bundled together.
+>   - The modules really rely on each other quite a bit.
+>   - It's tricky to scale features on their own.
+>   - Any updates mean we have to redeploy the whole app.
+> - `Transition to Microservices`: The monolithic app is split into smaller, independent services (Recruiters, Job Application, Job Vacancies).
+>   - Each service can be developed, deployed, and scaled independently.
+>   - Easier to maintain and adopt new technologies per service.
+> - `Docker`: Each microservice is packaged into application containers using Docker.
+>   - Provides portability across environments.
+>   - Ensures consistency between development and production.
+> - `Kubernetes`: Containers are deployed and managed in a Kubernetes cluster (K8s).
+>   - Handles orchestration: scaling, load balancing, self-healing.
+>   - Enables automated deployments and rolling updates.
+
+## Container related services
+
+> Typical Flow:
+
+1.  **Build image → Push to ACR**
+2.  **Choose deployment service:**
+    *   AKS (more flexible orchestration)
+    *   Container Apps (simpler, serverless)
+    *   ACI (quick jobs)
+3.  **Add storage if needed**
+4.  **Configure networking, scaling, monitoring**
+
+<div align="center">
+  <img width="750" height="677" alt="image" src="https://github.com/user-attachments/assets/400f5be2-45c2-4486-9c53-adf739aff4d0" />
+</div>
+
+<details>
+<summary><b> 1. Azure Container Registry (ACR)</b> (Click to expand)</summary>
+
+> This is where you store your container images (like Docker images). Think of it as your private container image repository.
+> - **When to use:** Almost always if you’re deploying containers in Azure. You build your app locally or in CI/CD, push the image to ACR, and then other services (AKS, Container Apps, etc.) pull from it.
+> - **Setup order:** Usually first, because your deployment services need access to the images.
+
+</details>
+
+<details>
+<summary><b>2. Azure Kubernetes Service (AKS)</b> (Click to expand)</summary>
+
+> A managed Kubernetes cluster for running containerized workloads at scale.
+> - **When to use:** If you need orchestration, scaling, and advanced networking for multiple containers or microservices.
+> - **Relation to ACR:** AKS pulls images from ACR to run your pods.
+> - **Setup order:** After ACR is ready and your images are pushed.
+
+</details>
+
+<details>
+<summary><b>3. Azure Container Apps</b> (Click to expand)</summary>
+
+> A serverless container platform for microservices and apps without managing Kubernetes directly.
+> - **When to use:** If you want simplicity from management perspective and autoscaling.
+> - **Relation to ACR:** Same as AKS, pulls images from ACR.
+> - **Setup order:** After ACR.
+
+</details>
+
+<details>
+<summary><b>4. Azure Container Instances (ACI)</b> (Click to expand)</summary>
+
+> Run containers quickly without orchestration, good for short-lived tasks or simple apps.
+> - **When to use:** For lightweight workloads or batch jobs.
+> - **Relation to ACR:** Can also pull images from ACR.
+
+</details>
+
+<details>
+<summary><b>5. Azure Container Storage</b> (Click to expand)</summary>
+
+> Persistent storage for stateful containers.
+> - **When to use:** If your containers need to keep data beyond their lifecycle (e.g., databases).
+> - **Setup order:** Alongside AKS or Container Apps if needed.
+
+</details>
+
+<details>
+<summary><b>6. Azure Kubernetes Service Edge Essentials</b> (Click to expand)</summary>
+
+> On-premises Kubernetes for edge scenarios.
+> - **When to use:** If you need hybrid or edge deployments.
+
+</details>
+
+## How to choose?
+
+<img width="900" height="916" alt="image" src="https://github.com/user-attachments/assets/259cba67-0742-4ff8-b9b5-4481772c04f9" />
+
+From [Choose an Azure compute service](https://learn.microsoft.com/en-us/azure/architecture/guide/technology-choices/compute-decision-tree)
+
+## Pricing example
+
+> AKS `itself is free`; you pay for:
+> - VMs in Node Pools (Standard vs Premium SSD, VM size)
+> - Networking (Azure CNI vs Kubenet)
+> - Storage
+> - Optional features (e.g., Azure Monitor, Virtual Nodes)
+> Your `node VM size and features define cost and performance.`
+
+How determine which **AKS tier** (or node size/configuration) you need, you can follow these steps:
+
+> [!NOTE]
+> Quick Way to Decide:
+- If you want **low cost** → B-series or Spot VMs.
+- If you want **balanced performance** → D-series.
+- If you need **high compute** → F-series or GPU nodes.
+
+1. Estimate Resource Requirements:
+  - **CPU & Memory per container**: Check your app’s baseline usage.
+  - **Number of containers per pod**: Multi-container apps share pod resources.
+  - **Expected traffic**: Peak vs average load.
+2. Use AKS Recommendations: 
+  - Enable **Cluster Autoscaler** and **Horizontal Pod Autoscaler**.
+  - Use **Azure Advisor** → It gives cost and performance recommendations based on telemetry.
+
+> [!TIP]
+> Use [Azure Pricing Calculator](https://azure.microsoft.com/en-us/pricing/calculator/?msockid=38ec3806873362243e122ce086486339) and **AKS Sizing Guide**:
+
+From AKS perspective we can choose between tier for the cluster management, click here for more details about [Free, Standard, and Premium pricing tiers for Azure Kubernetes Service (AKS) cluster management](https://learn.microsoft.com/en-us/azure/aks/free-standard-pricing-tiers)
+
+| **Feature**                 | **Free Tier** | **Standard Tier** | **Premium Tier** |
+| --------------------- | -------------------------------------------------- | ---------------------------------------- | ----------------------------------------------------------------------------------------------------------- |
+| **When to Use**             | - Experiment with AKS at no cost<br>- New to AKS/Kubernetes                                 | - Production or mission-critical workloads needing high availability<br>- Financially backed SLA    | - Mission-critical workloads requiring **two years** of Kubernetes version support<br>- Highest reliability |
+| **Supported Cluster Types** | - Dev/test clusters<br>- Clusters < 10 nodes                                                | - Enterprise-grade or production workloads<br>- Up to 5,000 nodes                                   | - Enterprise-grade or production workloads<br>- Up to 5,000 nodes                                           |
+| **Pricing**                 | - Free cluster management<br>- Pay-as-you-go for resources                                  | - Pay-as-you-go for resources<br>- [Standard tier cluster management pricing](https://azure.microsoft.com/en-us/pricing/details/kubernetes-service/)                         | - Pay-as-you-go for resources<br>- [Premium tier cluster management pricing](https://azure.microsoft.com/en-us/pricing/details/kubernetes-service/)|
+| **Feature Comparison**      | - Recommended for clusters < 10 nodes<br>- Supports up to 1,000 nodes<br>- All AKS features | - Uptime SLA enabled<br>- Greater reliability<br>- Supports up to 5,000 nodes<br>- All AKS features | - Includes all Standard tier features<br>- [Microsoft maintenance past community support](https://learn.microsoft.com/en-us/azure/aks/long-term-support)                     |
+
+> [!TIP]
+> Which Tier Should You Choose?
+> - **Free Tier** → Best for **testing or learning**, small clusters (<10 nodes).
+> - **Standard Tier** → Best for **production workloads**, SLA-backed, up to 5,000 nodes.
+> - **Premium Tier** → Best for **mission-critical workloads**, extended Kubernetes version support (2 years), and advanced reliability.
+
+<img width="1198" height="392" alt="image" src="https://github.com/user-attachments/assets/97244861-fd9c-476a-9a40-d90d49c18e0c" />
+
+> [!NOTE]
+> Cost Impact as today (check last updated date):
+> - **Free Tier**: $0 for cluster management, pay for nodes only.
+> - **Standard Tier**: Adds cluster management cost (usually $0.10/hour per cluster).
+> - **Premium Tier**: Higher cluster management cost + advanced support.
+
+E.g as today (check last updated date):
+
+<img width="1410" height="977" alt="image" src="https://github.com/user-attachments/assets/6992a004-c148-44f2-9235-4f00b988f255" />
+
+For VMs in Node Pools (Standard vs Premium SSD, VM size): 
+
+<img width="1217" height="972" alt="image" src="https://github.com/user-attachments/assets/accbab1c-4818-46db-ba5e-22dbc4a7b5ae" />
+
+- You can use `Microsoft Copilot in Azure` to find the `best VM size for you`. Click here to see the [demo on how to use it](https://www.youtube.com/watch?v=HGdhUFHnij4&t=819s).
+  - Copilot uses your `subscription details and resource availability to recommend the most suitable VM size.`
+  - It can also `assist with quota checks and guide you to request more capacity if needed.`
+
+    <img width="1910" height="1003" alt="image" src="https://github.com/user-attachments/assets/6deae8de-410f-478f-9327-a5af8b296fa3" />
+
+- And, Managed OS Disks in Azure are block-level storage volumes that are automatically managed by Azure for virtual machines. Click here to read more about [Azure managed disk types](https://learn.microsoft.com/en-us/azure/virtual-machines/disks-types)
+
+    <img width="1200" height="662" alt="image" src="https://github.com/user-attachments/assets/2d6773ce-45eb-4053-a1d1-791ab106d023" />
+
+From [Disk type comparison](https://learn.microsoft.com/en-us/azure/virtual-machines/disks-types#disk-type-comparison)
+
+## Best practices 
+
+- Cluster Size & Node Pools
+  - Use `Virtual Nodes or Burstable VMs (B-series) for cost efficiency.`
+  - `Spot instances for non-critical workloads.`
+- Autoscaling: Enable `Cluster Autoscaler to scale nodes dynamically.`
+- Container Registry: Use Azure Container Registry `(ACR) with geo-replication only if needed.`
+- Networking Costs: Minimize cross-region traffic;` keep AKS and app services in same region.`
+- Reserved Instances: For predictable workloads, `reserve VMs for 1–3 years to save up to ~57%.`
+
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