--- name: debug-buttercup description: "All pods run in namespace crs. Use when pods in the crs namespace are in CrashLoopBackOff, OOMKilled, or restarting, multiple services restart simultaneously (cascade failure), or redis is unresponsive or showing AOF warnings." risk: unknown source: community --- # 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) - Debugging issues outside the `crs` Kubernetes namespace - Performance tuning that doesn't involve a failure symptom ## Namespace and Services All pods run in namespace `crs`. Key services: | Layer | Services | |-------|----------| | Infra | redis, dind, litellm, registry-cache | | Orchestration | scheduler, task-server, task-downloader, scratch-cleaner | | Fuzzing | build-bot, fuzzer-bot, coverage-bot, tracer-bot, merger-bot | | Analysis | patcher, seed-gen, program-model, pov-reproducer | | Interface | competition-api, ui | ## Triage Workflow Always start with triage. Run these three commands first: ```bash # 1. Pod status - look for restarts, CrashLoopBackOff, OOMKilled kubectl get pods -n crs -o wide # 2. Events - the timeline of what went wrong kubectl get events -n crs --sort-by='.lastTimestamp' # 3. Warnings only - filter the noise kubectl get events -n crs --field-selector type=Warning --sort-by='.lastTimestamp' ``` Then narrow down: ```bash # Why did a specific pod restart? Check Last State Reason (OOMKilled, Error, Completed) kubectl describe pod -n crs | grep -A8 'Last State:' # Check actual resource limits vs intended kubectl get pod -n crs -o jsonpath='{.spec.containers[0].resources}' # Crashed container's logs (--previous = the container that died) kubectl logs -n crs --previous --tail=200 # Current logs kubectl logs -n crs --tail=200 ``` ### Historical vs Ongoing Issues 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. ## Log Analysis ```bash # All replicas of a service at once kubectl logs -n crs -l app=fuzzer-bot --tail=100 --prefix # Stream live kubectl logs -n crs -l app.kubernetes.io/name=redis -f # Collect all logs to disk (existing script) bash deployment/collect-logs.sh ``` ## Resource Pressure ```bash # Per-pod CPU/memory kubectl top pods -n crs # Node-level kubectl top nodes # Node conditions (disk pressure, memory pressure, PID pressure) kubectl describe node | grep -A5 Conditions # Disk usage inside a pod kubectl exec -n crs -- df -h # What's eating disk kubectl exec -n crs -- sh -c 'du -sh /corpus/* 2>/dev/null' kubectl exec -n crs -- sh -c 'du -sh /scratch/* 2>/dev/null' ``` ## Redis Debugging Redis is the backbone. When it goes down, everything cascades. ```bash # Redis pod status kubectl get pods -n crs -l app.kubernetes.io/name=redis # Redis logs (AOF warnings, OOM, connection issues) kubectl logs -n crs -l app.kubernetes.io/name=redis --tail=200 # Connect to Redis CLI kubectl exec -n crs -- redis-cli # Inside redis-cli: key diagnostics INFO memory # used_memory_human, maxmemory INFO persistence # aof_enabled, aof_last_bgrewrite_status, aof_delayed_fsync INFO clients # connected_clients, blocked_clients INFO stats # total_connections_received, rejected_connections CLIENT LIST # see who's connected DBSIZE # total keys # AOF configuration CONFIG GET appendonly # is AOF enabled? CONFIG GET appendfsync # fsync policy: everysec, always, or no # What is /data mounted on? (disk vs tmpfs matters for AOF performance) ``` ```bash kubectl exec -n crs -- mount | grep /data kubectl exec -n crs -- du -sh /data/ ``` ### Queue Inspection Buttercup uses Redis streams with consumer groups. Queue names: | Queue | Stream Key | |-------|-----------| | Build | fuzzer_build_queue | | Build Output | fuzzer_build_output_queue | | Crash | fuzzer_crash_queue | | Confirmed Vulns | confirmed_vulnerabilities_queue | | Download Tasks | orchestrator_download_tasks_queue | | Ready Tasks | tasks_ready_queue | | Patches | patches_queue | | Index | index_queue | | Index Output | index_output_queue | | Traced Vulns | traced_vulnerabilities_queue | | POV Requests | pov_reproducer_requests_queue | | POV Responses | pov_reproducer_responses_queue | | Delete Task | orchestrator_delete_task_queue | ```bash # Check stream length (pending messages) kubectl exec -n crs -- redis-cli XLEN fuzzer_build_queue # Check consumer group lag kubectl exec -n crs -- redis-cli XINFO GROUPS fuzzer_build_queue # Check pending messages per consumer kubectl exec -n crs -- redis-cli XPENDING fuzzer_build_queue build_bot_consumers - + 10 # Task registry size kubectl exec -n crs -- redis-cli HLEN tasks_registry # Task state counts kubectl exec -n crs -- redis-cli SCARD cancelled_tasks kubectl exec -n crs -- redis-cli SCARD succeeded_tasks kubectl exec -n crs -- redis-cli SCARD errored_tasks ``` Consumer groups: `build_bot_consumers`, `orchestrator_group`, `patcher_group`, `index_group`, `tracer_bot_group`. ## Health Checks Pods write timestamps to `/tmp/health_check_alive`. The liveness probe checks file freshness. ```bash # Check health file freshness kubectl exec -n crs -- stat /tmp/health_check_alive kubectl exec -n crs -- cat /tmp/health_check_alive ``` 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 -- 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 -- mount | grep corpus_tmpfs kubectl exec -n crs -- df -h /corpus_tmpfs 2>/dev/null # Check if CORPUS_TMPFS_PATH is set kubectl exec -n crs -- env | grep CORPUS # Full disk layout - what's on real disk vs tmpfs kubectl exec -n crs -- df -h ``` `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 -o jsonpath='{.spec.containers[0].resources}' # Check a pod's actual volume definitions kubectl get pod -n crs -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. Quick reference: - **DinD**: `kubectl logs -n crs -l app=dind --tail=100` -- look for docker daemon crashes, storage driver errors - **Build-bot**: check build queue depth, DinD connectivity, OOM during compilation - **Fuzzer-bot**: corpus disk usage, CPU throttling, crash queue backlog - **Patcher**: LiteLLM connectivity, LLM timeout, patch queue depth - **Scheduler**: the central brain -- `kubectl logs -n crs -l app=scheduler --tail=-1 --prefix | grep "WAIT_PATCH_PASS\|ERROR\|SUBMIT"` ## Diagnostic Script Run the automated triage snapshot: ```bash bash {baseDir}/scripts/diagnose.sh ``` Pass `--full` to also dump recent logs from all pods: ```bash bash {baseDir}/scripts/diagnose.sh --full ``` This collects pod status, events, resource usage, Redis health, and queue depths in one pass. ## Limitations - Use this skill only when the task clearly matches the scope described above. - Do not treat the output as a substitute for environment-specific validation, testing, or expert review. - Stop and ask for clarification if required inputs, permissions, safety boundaries, or success criteria are missing.

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