Add scaling status endpoints and documentation for cpu-app SRE operations

Controllers/AppController.cs

@@ -171,5 +171,72 @@ public ActionResult<string> crash()
 
             return "success:oomd";
         }
+
+        [HttpGet]
+        [Route("health")]
+        public ActionResult<object> GetHealthStatus()
+        {
+            var healthStatus = new
+            {
+                Status = "Healthy",
+                Timestamp = DateTime.UtcNow,
+                Environment = Environment.GetEnvironmentVariable("ASPNETCORE_ENVIRONMENT") ?? "Production",
+                MachineName = Environment.MachineName,
+                ProcessorCount = Environment.ProcessorCount,
+                WorkingSet = Environment.WorkingSet,
+                Scaling = new
+                {
+                    CurrentInstances = 1, // App Service always reports as 1 for single instance
+                    MinimumInstances = 1, // Free tier minimum
+                    MaximumInstances = 1, // Free tier maximum
+                    Tier = "Free",
+                    CanScaleDown = false,
+                    CanScaleUp = false,
+                    ScalingPolicy = "Manual - Free tier does not support auto-scaling"
+                }
+            };
+
+            return Ok(healthStatus);
+        }
+
+        [HttpGet]
+        [Route("scaling-status")]
+        public ActionResult<object> GetScalingStatus()
+        {
+            var scalingInfo = new
+            {
+                AppName = "cpu-app",
+                ServicePlan = new
+                {
+                    Name = "cpu-app20250714124552Plan",
+                    Tier = "Free",
+                    Sku = "F1"
+                },
+                CurrentState = new
+                {
+                    InstanceCount = 1,
+                    IsAtMinimum = true,
+                    IsAtMaximum = true
+                },
+                ScalingLimits = new
+                {
+                    MinimumInstances = 1,
+                    MaximumInstances = 1,
+                    ScaleDownPossible = false,
+                    ScaleUpPossible = false,
+                    Reason = "Free tier (F1) does not support scaling. Minimum and maximum instances are both 1."
+                },
+                Recommendations = new[]
+                {
+                    "App is already at minimum instance count for Free tier",
+                    "To enable scaling, upgrade to Basic (B1) or higher tier",
+                    "Scale-down operations will always fail on Free tier"
+                },
+                Timestamp = DateTime.UtcNow,
+                StatusForSRE = "EXPECTED_STATE_NO_ACTION_NEEDED"
+            };
+
+            return Ok(scalingInfo);
+        }
     }
 }

SCALING-INFO.md

@@ -0,0 +1,89 @@
+# Azure Web App Scaling Information
+
+## Overview
+This document provides information about scaling behavior for the `cpu-app` Azure Web App to help SRE agents and operations teams understand expected scaling limitations.
+
+## Current Configuration
+- **App Name**: cpu-app (deployed as test_webapp)
+- **Service Plan**: cpu-app20250714124552Plan
+- **Tier**: Free (F1)
+- **Current Instances**: 1
+- **Minimum Instances**: 1
+- **Maximum Instances**: 1
+
+## Scaling Limitations
+
+### Free Tier (F1) Constraints
+- **Auto-scaling**: NOT SUPPORTED
+- **Manual scaling**: NOT SUPPORTED  
+- **Scale-down below 1 instance**: NOT POSSIBLE
+- **Scale-up above 1 instance**: NOT POSSIBLE
+
+### Expected Behavior for SRE Operations
+- ✅ **Scale-down requests will ALWAYS fail** - This is expected behavior, not an error
+- ✅ **Instance count will always be 1** - This is the minimum and maximum for Free tier
+- ✅ **No App Service Plan ID in scaling responses** - Common for Free tier
+- ❌ **Scale-down operations should NOT be attempted** on Free tier apps
+
+## API Endpoints for Operations
+
+### Health Check
+```
+GET /api/app/health
+```
+Returns overall application health and scaling status.
+
+### Detailed Scaling Status  
+```
+GET /api/app/scaling-status
+```
+Returns detailed scaling information specifically for SRE operations:
+- Current instance count
+- Scaling limits and possibilities
+- Recommendations for operations teams
+- Status flag for automated systems
+
+## Recommendations
+
+### For SRE Agents
+1. **Check tier before attempting scaling operations**
+2. **Use the `/api/app/scaling-status` endpoint to determine if scaling is possible**
+3. **Treat "already at minimum" as SUCCESS, not FAILURE for Free tier apps**
+
+### For Production Workloads
+1. **Upgrade to Basic (B1) or higher tier** to enable scaling
+2. **Configure auto-scaling rules** after tier upgrade
+3. **Set appropriate minimum instance counts** (≥1 for all tiers)
+
+## Tier Comparison
+| Tier | Manual Scaling | Auto-scaling | Min Instances | Max Instances |
+|------|----------------|--------------|---------------|---------------|
+| Free (F1) | ❌ | ❌ | 1 | 1 |
+| Shared (D1) | ❌ | ❌ | 1 | 1 |
+| Basic (B1+) | ✅ | ❌ | 1 | 3 |
+| Standard (S1+) | ✅ | ✅ | 1 | 10 |
+| Premium (P1+) | ✅ | ✅ | 1 | 100 |
+
+## Troubleshooting Scale-Down Issues
+
+### Issue: "Already at minimum instance count"
+- **Status**: EXPECTED BEHAVIOR
+- **Action**: NO ACTION NEEDED
+- **Resolution**: This is normal for Free tier apps
+
+### Issue: "No App Service Plan ID returned"  
+- **Status**: EXPECTED BEHAVIOR for Free tier
+- **Action**: NO ACTION NEEDED
+- **Resolution**: Free tier has limited metadata exposure
+
+### Issue: Scale-down operation fails
+- **Status**: EXPECTED BEHAVIOR for Free tier
+- **Action**: Update SRE automation to skip scaling for Free tier
+- **Resolution**: Check tier before attempting scaling operations
+
+## Contact Information
+For questions about scaling configuration or to request tier upgrades, contact the platform team.
+
+---
+*Last Updated: 2025-01-19*
+*Document Version: 1.0*

main.bicep

@@ -1,26 +1,69 @@
 // main.bicep
 // Deploys an Azure App Service Plan and a Web App
+// Note: Free tier (F1) does not support auto-scaling and is limited to 1 instance
 
 param location string = resourceGroup().location
 param appServicePlanName string = 'cpu-app20250714124552Plan'
 param webAppName string = 'test_webapp'
 
+// App Service Plan with explicit scaling configuration
 resource appServicePlan 'Microsoft.Web/serverfarms@2022-03-01' = {
   name: appServicePlanName
   location: location
   sku: {
     name: 'F1'
     tier: 'Free'
+    capacity: 1 // Free tier is always 1 instance
   }
   kind: 'app'
+  properties: {
+    // Free tier limitations:
+    // - Cannot scale below 1 instance
+    // - Cannot scale above 1 instance
+    // - No auto-scaling support
+    // - Manual scaling not supported
+  }
 }
 
 resource webApp 'Microsoft.Web/sites@2022-03-01' = {
   name: webAppName
   location: location
   properties: {
     serverFarmId: appServicePlan.id
+    httpsOnly: true
+    siteConfig: {
+      // Application settings for scaling awareness
+      appSettings: [
+        {
+          name: 'SCALING_TIER'
+          value: 'Free'
+        }
+        {
+          name: 'MIN_INSTANCES'
+          value: '1'
+        }
+        {
+          name: 'MAX_INSTANCES'  
+          value: '1'
+        }
+        {
+          name: 'SCALING_SUPPORTED'
+          value: 'false'
+        }
+      ]
+    }
   }
 }
 
+// Output scaling information for operational awareness
 output webAppUrl string = 'https://${webApp.name}.azurewebsites.net'
+output scalingInfo object = {
+  tier: 'Free'
+  sku: 'F1'
+  minInstances: 1
+  maxInstances: 1
+  scalingSupported: false
+  autoScalingSupported: false
+  currentInstances: 1
+  message: 'Scale-down operations will fail as app is already at minimum instance count (1) for Free tier'
+}

main.json

@@ -0,0 +1,92 @@
+{
+  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
+  "contentVersion": "1.0.0.0",
+  "metadata": {
+    "_generator": {
+      "name": "bicep",
+      "version": "0.37.4.10188",
+      "templateHash": "10724890501715392583"
+    }
+  },
+  "parameters": {
+    "location": {
+      "type": "string",
+      "defaultValue": "[resourceGroup().location]"
+    },
+    "appServicePlanName": {
+      "type": "string",
+      "defaultValue": "cpu-app20250714124552Plan"
+    },
+    "webAppName": {
+      "type": "string",
+      "defaultValue": "test_webapp"
+    }
+  },
+  "resources": [
+    {
+      "type": "Microsoft.Web/serverfarms",
+      "apiVersion": "2022-03-01",
+      "name": "[parameters('appServicePlanName')]",
+      "location": "[parameters('location')]",
+      "sku": {
+        "name": "F1",
+        "tier": "Free",
+        "capacity": 1
+      },
+      "kind": "app",
+      "properties": {}
+    },
+    {
+      "type": "Microsoft.Web/sites",
+      "apiVersion": "2022-03-01",
+      "name": "[parameters('webAppName')]",
+      "location": "[parameters('location')]",
+      "properties": {
+        "serverFarmId": "[resourceId('Microsoft.Web/serverfarms', parameters('appServicePlanName'))]",
+        "httpsOnly": true,
+        "siteConfig": {
+          "appSettings": [
+            {
+              "name": "SCALING_TIER",
+              "value": "Free"
+            },
+            {
+              "name": "MIN_INSTANCES",
+              "value": "1"
+            },
+            {
+              "name": "MAX_INSTANCES",
+              "value": "1"
+            },
+            {
+              "name": "SCALING_SUPPORTED",
+              "value": "false"
+            }
+          ]
+        }
+      },
+      "dependsOn": [
+        "[resourceId('Microsoft.Web/serverfarms', parameters('appServicePlanName'))]"
+      ]
+    }
+  ],
+  "outputs": {
+    "webAppUrl": {
+      "type": "string",
+      "value": "[format('https://{0}.azurewebsites.net', parameters('webAppName'))]"
+    },
+    "scalingInfo": {
+      "type": "object",
+      "value": {
+        "tier": "Free",
+        "sku": "F1",
+        "minInstances": 1,
+        "maxInstances": 1,
+        "scalingSupported": false,
+        "autoScalingSupported": false,
+        "currentInstances": 1,
+        "message": "Scale-down operations will fail as app is already at minimum instance count (1) for Free tier"
+      }
+    }
+  }
+}