/debug-build Skill

Diagnose OpenShift build failures by automatically gathering BuildConfig, Build status, build pod logs, and related resources.

Prerequisites

Before running this skill:

User is logged into OpenShift cluster
User has access to the target namespace
Build or BuildConfig name is known (or can be identified from recent builds)

When to Use This Skill

Use this skill when OpenShift builds fail, hang, or produce unexpected results. It diagnoses S2I builds, Docker/Podman builds, and BuildConfig issues by analyzing build pod logs, registry authentication, and source repository access.

Critical: Human-in-the-Loop Requirements

See Human-in-the-Loop Requirements for mandatory checkpoint behavior.

Workflow

Step 1: Identify Target Build

## Build Debugging

**Current OpenShift Context:**
- Cluster: [cluster]
- Namespace: [namespace]

Which build would you like me to debug?

1. **Specify build name** - Enter the build name directly (e.g., myapp-1)
2. **List failed builds** - Show recent failed builds in current namespace
3. **From BuildConfig** - Debug latest build from a specific BuildConfig

Select an option or enter a build name:

WAIT for user confirmation before proceeding.

If user selects "List failed builds": Use kubernetes MCP resources_list for builds, filter by Failed phase:

## Recent Failed Builds in [namespace]

| Build | BuildConfig | Status | Started | Duration |
|-------|-------------|--------|---------|----------|
| [app-1] | [app] | Failed | [timestamp] | [duration] |
| [app-2] | [app] | Cancelled | [timestamp] | [duration] |
| [other-1] | [other] | Failed | [timestamp] | [duration] |

Which build would you like me to debug?

WAIT for user to select a build.

Step 2: Get Build Status Overview

Use kubernetes MCP resources_get to get Build details:

## Build Status: [build-name]

**Build Info:**
| Field | Value |
|-------|-------|
| BuildConfig | [buildconfig-name] |
| Strategy | [Source/Docker/JenkinsPipeline] |
| Phase | [New/Pending/Running/Complete/Failed/Cancelled] |
| Started | [timestamp] |
| Completed | [timestamp or "Still running"] |
| Duration | [duration] |

**Build Configuration:**
| Setting | Value |
|---------|-------|
| Source Type | [Git/Binary/Dockerfile] |
| Git URL | [url] |
| Git Ref | [branch/tag] |
| Builder Image | [image:tag] |
| Output Image | [imagestream:tag] |

**Build Status:**
- Phase: [phase]
- Reason: [reason if failed]
- Message: [message if available]

**Quick Assessment:**
[Based on status, provide initial assessment - e.g., "Build failed during assemble phase - likely dependency installation issue"]

Continue with detailed analysis? (yes/no)

WAIT for user confirmation before proceeding.

Step 3: Analyze BuildConfig

Use kubernetes MCP resources_get to get BuildConfig:

## BuildConfig Analysis: [buildconfig-name]

**Source Configuration:**
| Setting | Value | Status |
|---------|-------|--------|
| Git URL | [url] | [OK/WARN: check access] |
| Git Ref | [ref] | [OK/WARN: branch not found] |
| Context Dir | [dir or "/"] | [OK] |
| Source Secret | [secret-name or "None"] | [OK/MISSING] |

**Builder Image:**
| Setting | Value | Status |
|---------|-------|--------|
| Image | [image:tag] | [OK/WARN: check exists] |
| Pull Secret | [secret-name or "None"] | [OK/MISSING] |

**Output Configuration:**
| Setting | Value | Status |
|---------|-------|--------|
| Output To | [ImageStreamTag] | [OK] |
| Push Secret | [secret-name or "None"] | [OK/MISSING] |

**Environment Variables:**
| Name | Value | Source |
|------|-------|--------|
| [VAR] | [value or "***"] | [Direct/ConfigMap/Secret] |

**Issues Found:**
- [Issue 1 - e.g., "Source secret 'github-creds' referenced but not found"]
- [Issue 2 - e.g., "Builder image uses older tag, may have compatibility issues"]

Continue to view build logs? (yes/no)

WAIT for user confirmation before proceeding.

Step 4: Get Build Pod Logs

Use kubernetes MCP pod_logs for the builder pod:

## Build Logs: [build-name]

**Build Phases:**
| Phase | Status | Duration |
|-------|--------|----------|
| Fetching source | [Complete/Failed] | [duration] |
| Pulling builder image | [Complete/Failed] | [duration] |
| Assemble | [Complete/Failed] | [duration] |
| Commit | [Complete/Failed] | [duration] |
| Push | [Complete/Failed] | [duration] |

**Failed Phase: [phase-name]**

[Last 100 lines of build logs, focused on the failing phase]


**Log Analysis:**

[Analyze logs and identify errors:]

**Errors Found:**
- Line [X]: [error description - e.g., "npm ERR! 404 Not Found - package 'nonexistent@1.0.0'"]
- Line [Y]: [error description - e.g., "error: unable to resolve 'github.com/private/repo'"]

**S2I Phase Explanation:**

[For S2I builds, explain what the failed phase does:]
- **assemble**: Installs dependencies and builds application
- **commit**: Creates the final container image layer
- **push**: Pushes image to internal registry

Continue to check related resources? (yes/no)

WAIT for user confirmation before proceeding.

Step 5: Check Related Resources

Check secrets, imagestreams, and source access:

## Related Resources Analysis

**ImageStreams:**
| ImageStream | Tags | Last Updated | Status |
|-------------|------|--------------|--------|
| [app] | [latest, v1.0] | [timestamp] | [OK] |
| [builder] | [imported] | [timestamp] | [OK/MISSING] |

**Secrets:**
| Secret | Type | Used By | Status |
|--------|------|---------|--------|
| [source-secret] | kubernetes.io/basic-auth | Source | [OK/MISSING] |
| [push-secret] | kubernetes.io/dockerconfigjson | Output | [OK/MISSING] |

**Source Repository Access:**
[If GitHub MCP available, check if source URL is accessible]
- URL: [git-url]
- Status: [Accessible/401 Unauthorized/404 Not Found/Timeout]

**Registry Access:**
[Check if internal registry is accessible]
- Registry: image-registry.openshift-image-registry.svc:5000
- Status: [OK/Unreachable]

**Issues Found:**
- [Issue 1 - e.g., "Secret 'github-token' missing - cannot authenticate to private repo"]
- [Issue 2 - e.g., "Builder ImageStreamTag 'nodejs:18' not imported"]

Continue to full diagnosis summary? (yes/no)

WAIT for user confirmation before proceeding.

Step 6: Present Diagnosis Summary

## Diagnosis Summary: [build-name]

### Root Cause

**Primary Issue:** [Categorized root cause]

| Category | Status | Details |
|----------|--------|---------|
| Source Access | [OK/FAIL] | [details] |
| Builder Image | [OK/FAIL] | [details] |
| Dependencies | [OK/FAIL] | [details] |
| Build Script | [OK/FAIL] | [details] |
| Registry Push | [OK/FAIL] | [details] |

### Detailed Findings

**[Category 1: e.g., Dependency Installation]**
- Problem: [specific problem - e.g., "npm package 'lodash@99.0.0' does not exist"]
- Evidence: [from build logs]
- Impact: [build fails during assemble phase]

**[Category 2: e.g., Source Authentication]**
- Problem: [specific problem]
- Evidence: [from events/logs]
- Impact: [cannot clone repository]

### Recommended Actions

1. **[Action 1]** - [description]
   ```bash
   [command to fix - e.g., oc create secret generic github-token --from-literal=...]

[Action 2] - [description]

[command to fix - e.g., oc import-image nodejs:18 --from=registry.access.redhat.com/ubi9/nodejs-18]

[Action 3] - [description]

Retry Build

After fixing the issue:

# Start a new build
oc start-build [buildconfig-name] -n [namespace]

# Or start build with follow
oc start-build [buildconfig-name] -n [namespace] --follow

Would you like me to:

Execute one of the recommended fixes
Retry the build
Compare with last successful build
Debug the build pod (/debug-pod)
Exit debugging

Select an option:


**WAIT for user to select next action.**

## Build Failure Categories

For S2I build phase failures, common error patterns (Node.js, Python, Java), and troubleshooting decision trees, see [docs/debugging-patterns.md](../../docs/debugging-patterns.md).

## Dependencies

### Required MCP Servers
- `openshift` - Kubernetes/OpenShift resource access for builds, BuildConfigs, and build pod logs

### Related Skills
- `/s2i-build` - To retry build after fixing issues
- `/debug-pod` - To debug the builder pod directly
- `/deploy` - To deploy after a successful build

### Reference Documentation
- [docs/builder-images.md](../../docs/builder-images.md) - S2I builder image selection, version mapping
- [docs/python-s2i-entrypoints.md](../../docs/python-s2i-entrypoints.md) - Python APP_MODULE configuration
- [docs/debugging-patterns.md](../../docs/debugging-patterns.md) - Common error patterns
- [docs/prerequisites.md](../../docs/prerequisites.md) - Required tools (oc), cluster access verification