Debugs the Buttercup CRS (Cyber Reasoning System) running on Kubernetes. Use when diagnosing pod crashes, restart loops, Redis failures, resource pressure, disk saturation, DinD issues, or any service misbehavior in the crs namespace. Covers triage, log analysis, queue
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Debugs the Buttercup CRS (Cyber Reasoning System) running on Kubernetes. Use when diagnosing pod crashes, restart loops, Redis failures, resource pressure, disk saturation, DinD issues, or any service misbehavior in the crs namespace. Covers triage, log analysis, queue
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</> SKILL.md
debug-buttercup.SKILL.md
---name: debug-buttercup
description: >
Debugs the Buttercup CRS (Cyber Reasoning System) running on Kubernetes.
Use when diagnosing pod crashes, restart loops, Redis failures, resource pressure,
disk saturation, DinD issues, or any service misbehavior in the crs namespace.
Covers triage, log analysis, queue inspection, and common failure patterns
for: redis, fuzzer-bot, coverage-bot, seed-gen, patcher, build-bot, scheduler,
task-server, task-downloader, program-model, litellm, dind, tracer-bot,
merger-bot, competition-api, pov-reproducer, scratch-cleaner, registry-cache,
image-preloader, ui.
---# Debug Buttercup
## When to Use
- Pods in the `crs` namespace are in CrashLoopBackOff, OOMKilled, or restarting
- Multiple services restart simultaneously (cascade failure)
- Redis is unresponsive or showing AOF warnings
- Queues are growing but tasks are not progressing
- Nodes show DiskPressure, MemoryPressure, or PID pressure
- Build-bot cannot reach the Docker daemon (DinD failures)
- Scheduler is stuck and not advancing task state
- Health check probes are failing unexpectedly
- Deployed Helm values don't match actual pod configuration
## When NOT to Use
- Deploying or upgrading Buttercup (use Helm and deployment guides)
High restart counts don't necessarily mean an issue is ongoing -- restarts accumulate over a pod's lifetime. Always distinguish:
- `--tail` shows the end of the log buffer, which may contain old messages. Use `--since=300s` to confirm issues are actively happening now.
- `--timestamps` on log output helps correlate events across services.
- Check `Last State` timestamps in `describe pod` to see when the most recent crash actually occurred.
### Cascade Detection
When many pods restart around the same time, check for a shared-dependency failure before investigating individual pods. The most common cascade: Redis goes down -> every service gets `ConnectionError`/`ConnectionRefusedError` -> mass restarts. Look for the same error across multiple `--previous` logs -- if they all say `redis.exceptions.ConnectionError`, debug Redis, not the individual services.
If a pod is restart-looping, the health check file is likely going stale because the main process is blocked (e.g. waiting on Redis, stuck on I/O).
## Telemetry (OpenTelemetry / Signoz)
All services export traces and metrics via OpenTelemetry. If Signoz is deployed (`global.signoz.deployed: true`), use its UI for distributed tracing across services.
```bash
# Check if OTEL is configured
kubectl exec -n crs <pod> -- env | grep OTEL
# Verify Signoz pods are running (if deployed)
kubectl get pods -n platform -l app.kubernetes.io/name=signoz
```
Traces are especially useful for diagnosing slow task processing, identifying which service in a pipeline is the bottleneck, and correlating events across the scheduler -> build-bot -> fuzzer-bot chain.
## Volume and Storage
```bash
# PVC status
kubectl get pvc -n crs
# Check if corpus tmpfs is mounted, its size, and backing type
kubectl exec -n crs <pod> -- mount | grep corpus_tmpfs
`CORPUS_TMPFS_PATH` is set when `global.volumes.corpusTmpfs.enabled: true`. This affects fuzzer-bot, coverage-bot, seed-gen, and merger-bot.
### Deployment Config Verification
When behavior doesn't match expectations, verify Helm values actually took effect:
```bash
# Check a pod's actual resource limits
kubectl get pod -n crs <pod-name> -o jsonpath='{.spec.containers[0].resources}'
# Check a pod's actual volume definitions
kubectl get pod -n crs <pod-name> -o jsonpath='{.spec.volumes}'
```
Helm values template typos (e.g. wrong key names) silently fall back to chart defaults. If deployed resources don't match the values template, check for key name mismatches.
## Service-Specific Debugging
For detailed per-service symptoms, root causes, and fixes, see [references/failure-patterns.md](references/failure-patterns.md).
