# Application Gateway Troubleshooting

> Troubleshooting Application Gateway Problems

- Skill: `holmesgpt/application-gateway-troubleshooting` (Agent Skill)
- Install (CLI): `npx skillmds@latest add holmesgpt/application-gateway-troubleshooting`
- Raw SKILL.md: https://api.skillmd.com/api/skills/holmesgpt/application-gateway-troubleshooting/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: AI & ML
- Author: holmesgpt (https://skillmd.com/u/holmesgpt)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/holmesgpt/application-gateway-troubleshooting

---

# Application Gateway Troubleshooting

## Overview
This runbook helps troubleshoot common Application Gateway issues including 502 Bad Gateway errors.

## Prerequisites
- kubectl access to the cluster
- Ability to view pod logs

## Troubleshooting Steps

### Step 1: Find the Application Gateway Pod Status
Use kubectl to check if the Application Gateway pod is running:
```bash
kubectl get pods -n <namespace> | grep application-gateway
```

### Step 2: Check Application Gateway error Logs
Review the Application Gateway error logs for any issues:
```bash
kubectl logs <application-gateway-pod> -n <namespace> --tail=100 | grep -i error
```

### Step 3: Verify Upstream Services
Check if the upstream services that Application Gateway proxies to are healthy:
```bash
kubectl get pods -n <application-gateway-pod> -l app=upstream-service
```

### Step 4: Check Application Gateway Configuration
Verify the Application Gateway configuration is valid:
```bash
kubectl exec <application-gateway-pod> -n <namespace> -- appg -t
```

### Step 5: Review Service Endpoints
Ensure the Application Gateway has healthy endpoints:
```bash
kubectl get endpoints -n <namespace>
```

## Resolution Steps
Based on findings:
- If upstream is down: Restart upstream services
- If config invalid: Fix configuration and reload
- If no endpoints: Check service selectors