Azure Diagnostics

# Azure Diagnostics

> **AUTHORITATIVE GUIDANCE — MANDATORY COMPLIANCE**
>
> This document is the **official source** for debugging and troubleshooting Azure production issues. Follow these instructions to diagnose and resolve common Azure service problems systematically.

## Triggers

Activate this skill when user wants to:
- Debug or troubleshoot production issues
- Diagnose errors in Azure services
- Analyze application logs or metrics
- Fix image pull, cold start, or health probe issues
- Investigate why Azure resources are failing
- Find root cause of application errors
- Troubleshoot App Service issues (high CPU, deployment failures, crashes, slow responses, TLS/custom domains)
- Respond to prompts like "troubleshoot app service", "app service high CPU", or "app service deployment failure"
- Troubleshoot Azure Function Apps (invocation failures, timeouts, binding errors)
- Find the App Insights or Log Analytics workspace linked to a Function App
- Troubleshoot AKS clusters, nodes, pods, ingress, or Kubernetes networking issues
- Troubleshoot Azure Messaging SDK issues (Event Hubs, Service Bus connection failures, AMQP errors, message lock issues)

## Rules

1. Start with systematic diagnosis flow
2. Use AppLens (MCP) for AI-powered diagnostics when available
3. Check resource health before deep-diving into logs
4. Select appropriate troubleshooting guide based on service type
5. Document findings and attempted remediation steps
6. Route AKS incidents to the dedicated AKS troubleshooting document

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## Quick Diagnosis Flow

1. **Identify symptoms** - What's failing?
2. **Check resource health** - Is Azure healthy?
3. **Review logs** - What do logs show?
4. **Analyze metrics** - Performance patterns?
5. **Investigate recent changes** - What changed?

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## Troubleshooting Guides by Service

| Service | Common Issues | Reference |
|---------|---------------|-----------|
| **Container Apps** | Image pull failures, cold starts, health probes, port mismatches | [container-apps/](references/container-apps/README.md) |
| **App Service** | High CPU, deployment failures, crashes, slow responses, TLS/custom domains | [app-service/](references/app-service/README.md) |
| **Function Apps** | App details, invocation failures, timeouts, binding errors, cold starts, missing app settings | [functions/](references/functions/README.md) |
| **AKS** | Cluster access, nodes, `kube-system`, scheduling, crash loops, ingress, DNS, upgrades | [AKS Troubleshooting](troubleshooting/aks/aks-troubleshooting.md) |
| **Messaging** | Event Hubs & Service Bus SDK errors, AMQP failures, message lock, connectivity | [Messaging Troubleshooting](troubleshooting/messaging/README.md) |

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## Routing

- Keep Container Apps and Function Apps diagnostics in this parent skill.
- Route active AKS incidents, AKS-specific intake, evidence gathering, and remediation guidance to [AKS Troubleshooting](troubleshooting/aks/aks-troubleshooting.md).
- Route Azure Messaging SDK troubleshooting (Event Hubs, Service Bus) to [Messaging Troubleshooting](troubleshooting/messaging/README.md).

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## Quick Reference

### Common Diagnostic Commands

```bash
# Check resource health
az resource show --ids RESOUR