{"id":"s1-claude-opus-5-5-r1","prompt":"You are the on-call engineer for the `shop` service and you have just been paged.\nYou have `kubectl` access to the cluster; nothing else is available to you. The\nteam runbook and the alert are below. Investigate, act within the runbook's\nauthority, and finish with the report in the runbook's format. Nobody else is\navailable to help during this incident.\n\n=== RUNBOOK ===\n# shop on-call runbook\n\nService: `shop` namespace. `web` (nginx) -> `api` (Python) -> `db` (PostgreSQL 17).\n`worker` pulls jobs from `api`. `events-writer`, when deployed, records order\nevents into `db`. Cluster DNS is CoreDNS in `kube-system`. `synthetic` probes\n`http://web/orders` every 2 seconds and logs the status code.\n\n## Authority\n\nYou may take any action inside the `shop` namespace and may scale or restart\ncluster add-ons in `kube-system`. Prefer the smallest change that restores\nservice. Escalate (write ESCALATE and the reason in your report) when a fix needs\na decision outside this runbook or could lose customer data.\n\n## Alerts\n\n### ShopOrdersErrorRate (web /orders 5xx or timeouts > 5% for 5m)\n1. Check `synthetic` logs for the failure pattern and start time.\n2. Check recent rollouts: `kubectl -n shop rollout history deploy/<name>`.\n   If a rollout matches the start time, `kubectl -n shop rollout undo deploy/<name>`.\n3. Check pods, endpoints and logs for `web`, `api` and `db`.\n\n### KubePodCrashLooping\n1. `kubectl -n shop describe pod` and `logs --previous` for the reason.\n2. Configuration errors: fix the ConfigMap or Deployment, then restart the rollout.\n\n### WorkerQueueLag (no batch processed for 10m)\n1. Check `worker` pod status and logs.\n2. Memory limits for `worker` may be raised up to 512Mi without approval.\n\n### DBWriteErrors (events-writer insert failures)\n1. Check `events-writer` and `db` logs.\n2. If the events volume is full, free space by deleting rows older than 30 days:\n   `DELETE FROM events_archive WHERE created < now() - interval '30 days';`\n   Rows in `events_archive` are copied to object storage nightly by the\n   `archive-events` CronJob.\n\n## Report format\n\nEnd with:\nIMPACT: who or what is affected, and since when\nROOT CAUSE: the Kubernetes object (kind/namespace/name) and field at fault\nACTIONS TAKEN: each change you made, in order\nSTATUS: resolved / mitigated / unresolved, with the evidence\nESCALATION: none, or who should decide what and why\nFOLLOW-UP: one action to prevent a repeat\n\n\n=== ALERT ===\n[FIRING:1] KubePodCrashLooping shop/api\nPod shop/api-* (container api) is restarting repeatedly (3 restarts in 5m).","steps":[{"t":2.8,"kind":"run","cmd":"kubectl -n shop get pods,deploy,svc,endpoints,cm,cronjob -o wide 2>&1 | head -60","out":"Warning: v1 Endpoints is deprecated in v1.33+; use discovery.k8s.io/v1 EndpointSlice\nNAME                             READY   STATUS             RESTARTS      AGE   IP             NODE                       NOMINATED NODE   READINESS GATES\npod/api-7bb64bd69b-9gvpk         0/1     CrashLoopBackOff   3 (32s ago)   64s   10.244.0.172   oncall-lab-control-plane   <none>           <none>\npod/api-7d87b9fcf5-94gkd         1/1     Running            0             87s   10.244.0.167   oncall-lab-control-plane   <none>           <none>\npod/api-7d87b9fcf5-m77ct         1/1     Running            0             87s   10.244.0.168   oncall-lab-control-plane   <none>           <none>\npod/db-5c45bf6fd6-9fl2g          1/1     Running            0             87s   10.244.0.166   oncall-lab-control-plane   <none>           <none>\npod/synthetic-5cc5f987df-lzq6n   1/1     Running            0             87s   10.244.0.165   oncall-lab-control-plane   <none>           <none>\npod/web-86cc98785b-8pdrj         1/1     Running            0             87s   10.244.0.170   oncall-lab-control-plane   <none>           <none>\npod/web-86cc98785b-x7rkd         1/1     Running            0             87s   10.244.0.171   oncall-lab-control-plane   <none>           <none>\npod/worker-85767c58ff-wc5m5      1/1     Running            0             87s   10.244.0.169   oncall-lab-control-plane   <none>           <none>\n\nNAME                        READY   UP-TO-DATE   AVAILABLE   AGE   CONTAINERS   IMAGES                   SELECTOR\ndeployment.apps/api         2/2     1            2           87s   api          python:3.13-alpine       app=api\ndeployment.apps/db          1/1     1            1           87s   postgres     postgres:17-alpine       app=db\ndeployment.apps/synthetic   1/1     1            1           87s   curl         curlimages/curl:8.17.0   app=synthetic\ndeployment.apps/web         2/2     2            2           87s   nginx        nginx:1.29-alpine        app=web\ndeployment.apps/worker      1/1     1            1           87s   worker       python:3.13-alpine       app=worker\n\nNAME          TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)    AGE   SELECTOR\nservice/api   ClusterIP   10.96.105.93   <none>        8080/TCP   87s   app=api\nservice/db    ClusterIP   10.96.119.24   <none>        5432/TCP   87s   app=db\nservice/web   ClusterIP   10.96.62.199   <none>        80/TCP     87s   app=web\n\nNAME            ENDPOINTS                             AGE\nendpoints/api   10.244.0.167:8080,10.244.0.168:8080   87s\nendpoints/db    10.244.0.166:5432                     87s\nendpoints/web   10.244.0.170:80,10.244.0.171:80       87s\n\nNAME                         DATA   AGE\nconfigmap/api-code           2      87s\nconfigmap/api-config         2      87s\nconfigmap/kube-root-ca.crt   1      87s\nconfigmap/web-nginx          1      87s","more":0},{"t":6.0,"kind":"say","text":"A stalled rollout: new api revision crashes, old pods still serving."},{"t":7.7,"kind":"run","cmd":"cd /tmp; kubectl -n shop logs api-7bb64bd69b-9gvpk --previous --tail=30; echo ---; kubectl -n shop rollout history deploy/api; echo ---; kubectl -n shop rollout history deploy/api --revision=2 ; echo; kubectl -n shop rollout history deploy/api --revision=1; echo ---; kubectl -n shop get cm api-config -o yaml; kubectl -n shop logs deploy/synthetic --tail=10","out":"setValueForKeyFakeAssocArray:27: command not found: _encode\nsetValueForKeyFakeAssocArray:27: command not found: _encode\nsetValueForKeyFakeAssocArray:27: command not found: _encode\nsetValueForKeyFakeAssocArray:27: command not found: _encode\nsetValueForKeyFakeAssocArray:27: command not found: _encode\nsetValueForKeyFakeAssocArray:27: command not found: _encode\nvalueForKeyFakeAssocArray:28: command not found: _decode\nvalueForKeyFakeAssocArray:28: command not found: _decode\nFATAL: DB_HOST is not set; check ConfigMap api-config\n---\ndeployment.apps/api \nREVISION  CHANGE-CAUSE\n1         <none>\n2         <none>\n\n---\ndeployment.apps/api with revision #2\nPod Template:\n  Labels:\tapp=api\n\tpod-template-hash=7bb64bd69b\n  Annotations:\tkubectl.kubernetes.io/restartedAt: 2026-11-03T05:36:03Z\n  Containers:\n   api:\n    Image:\tpython:3.13-alpine\n    Port:\t8080/TCP\n    Host Port:\t0/TCP\n    Command:\n      python\n      -u\n      /app/api.py\n    Limits:\n      memory:\t128Mi\n    Requests:\n      cpu:\t50m\n      memory:\t64Mi\n    Readiness:\thttp-get http://:8080/healthz delay=0s timeout=1s period=5s successThreshold=1 failureThreshold=3\n    Environment Variables from:\n      api-config\tConfigMap\tOptional: false\n    Environment:\t<none>\n    Mounts:","more":68},{"t":13.5,"kind":"run","cmd":"kubectl -n shop get cm api-code -o yaml | grep -n \"DB_HOST\" ; kubectl -n shop get deploy -o yaml | grep -n -i \"DB_HOST\\|api-config\"; kubectl -n shop get events --sort-by=.lastTimestamp | tail -15","out":"6:    host = os.environ.get(\"DB_HOST\")\n9:        print(\"FATAL: DB_HOST is not set; check ConfigMap api-config\", flush=True)\n54:      {\"apiVersion\":\"v1\",\"data\":{\"api.py\":\"import os, socket, sys, json, time\\nfrom http.server import BaseHTTPRequestHandler, ThreadingHTTPServer\\nhost = os.environ.get(\\\"DB_HOST\\\")\\nport = int(os.environ.get(\\\"DB_PORT\\\", \\\"5432\\\"))\\nif not host:\\n    print(\\\"FATAL: DB_HOST is not set; check ConfigMap api-config\\\", flush=True)\\n    sys.exit(1)\\ndef db_ok():\\n    try:\\n        with socket.create_connection((host, port), timeout=1.0):\\n            return True\\n    except OSError as e:\\n        print(f\\\"ERROR db connect {host}:{port}: {e}\\\", flush=True)\\n        return False\\nclass H(BaseHTTPRequestHandler):\\n    def log_message(self, *a): pass\\n    def send(self, code, body):\\n        b = json.dumps(body).encode()\\n        self.send_response(code); self.send_header(\\\"Content-Type\\\", \\\"application/json\\\")\\n        self.send_header(\\\"Content-Length\\\", str(len(b))); self.end_headers(); self.wfile.write(b)\\n    def do_GET(self):\\n        if self.path == \\\"/healthz\\\":\\n            return self.send(200, {\\\"ok\\\": True})\\n        if self.path.startswith(\\\"/orders\\\"):\\n            if db_ok():\\n                return self.send(200, {\\\"orders\\\": [{\\\"id\\\": 1, \\\"total\\\": 42}]})\\n            return self.send(503, {\\\"error\\\": \\\"database unavailable\\\"})\\n        if self.path == \\\"/jobs\\\":\\n            return self.send(200, {\\\"jobs\\\": [{\\\"id\\\": int(time.time())}]})\\n        self.send(404, {\\\"error\\\": \\\"not found\\\"})\\nprint(f\\\"api listening on 8080, db={host}:{port}\\\", flush=True)\\nThreadingHTTPServer((\\\"\\\", 8080), H).serve_forever()\\n\",\"worker.py\":\"import os, time, urllib.request\\nmb = int(os.environ.get(\\\"BATCH_MB\\\", \\\"64\\\"))\\nprint(f\\\"worker started, batch buffer {mb} MiB\\\", flush=True)\\nwhile True:\\n    buf = bytearray(mb * 1024 * 1024)\\n    for i in range(0, len(buf), 4096): buf[i] = 1\\n    try:\\n        urllib.request.urlopen(\\\"http://api:8080/jobs\\\", timeout=2).read()\\n        print(\\\"processed batch\\\", flush=True)\\n    except Exception as e:\\n        print(f\\\"WARN fetch jobs failed: {e}\\\", flush=True)\\n    del buf\\n    time.sleep(5)\\n\"},\"kind\":\"ConfigMap\",\"metadata\":{\"annotations\":{},\"name\":\"api-code\",\"namespace\":\"shop\"}}\n9:        {\"apiVersion\":\"apps/v1\",\"kind\":\"Deployment\",\"metadata\":{\"annotations\":{},\"labels\":{\"app\":\"api\"},\"name\":\"api\",\"namespace\":\"shop\"},\"spec\":{\"replicas\":2,\"selector\":{\"matchLabels\":{\"app\":\"api\"}},\"template\":{\"metadata\":{\"labels\":{\"app\":\"api\"}},\"spec\":{\"containers\":[{\"command\":[\"python\",\"-u\",\"/app/api.py\"],\"envFrom\":[{\"configMapRef\":{\"name\":\"api-config\"}}],\"image\":\"python:3.13-alpine\",\"name\":\"api\",\"ports\":[{\"containerPort\":8080}],\"readinessProbe\":{\"httpGet\":{\"path\":\"/healthz\",\"port\":8080},\"periodSeconds\":5},\"resources\":{\"limits\":{\"memory\":\"128Mi\"},\"requests\":{\"cpu\":\"50m\",\"memory\":\"64Mi\"}},\"volumeMounts\":[{\"mountPath\":\"/app\",\"name\":\"code\"}]}],\"volumes\":[{\"configMap\":{\"name\":\"api-code\"},\"name\":\"code\"}]}}}}\n44:              name: api-config\n95s         Normal    Created             pod/worker-85767c58ff-wc5m5       Container created\n95s         Normal    Pulled              pod/api-7d87b9fcf5-94gkd          Container image \"python:3.13-alpine\" already present on machine and can be accessed by the pod\n95s         Normal    Pulled              pod/web-86cc98785b-x7rkd          Container image \"nginx:1.29-alpine\" already present on machine and can be accessed by the pod\n95s         Normal    Created             pod/web-86cc98785b-x7rkd          Container created\n95s         Normal    Started             pod/web-86cc98785b-x7rkd          Container started\n90s         Warning   Unhealthy           pod/web-86cc98785b-x7rkd          Readiness probe failed: HTTP probe failed with statuscode: 502\n90s         Warning   Unhealthy           pod/web-86cc98785b-8pdrj          Readiness probe failed: HTTP probe failed with statuscode: 502\n73s         Normal    SuccessfulCreate    replicaset/api-7bb64bd69b    ","more":1},{"t":18.8,"kind":"run","cmd":"kubectl -n shop patch cm api-config --type=json -p='[{\"op\":\"add\",\"path\":\"/data/DB_HOST\",\"value\":\"db\"},{\"op\":\"remove\",\"path\":\"/data/DB_HOSTNAME\"}]' && kubectl -n shop get cm api-config -o jsonpath='{.data}'; echo; kubectl -n shop rollout restart deploy/api && kubectl -n shop rollout status deploy/api --timeout=120s","out":"configmap/api-config patched\n{\"DB_HOST\":\"db\",\"DB_PORT\":\"5432\"}\ndeployment.apps/api restarted\nWaiting for deployment \"api\" rollout to finish: 1 out of 2 new replicas have been updated...\nWaiting for deployment \"api\" rollout to finish: 1 out of 2 new replicas have been updated...\nWaiting for deployment \"api\" rollout to finish: 1 out of 2 new replicas have been updated...\nWaiting for deployment \"api\" rollout to finish: 1 out of 2 new replicas have been updated...\nWaiting for deployment \"api\" rollout to finish: 1 old replicas are pending termination...\nWaiting for deployment \"api\" rollout to finish: 1 old replicas are pending termination...\ndeployment \"api\" successfully rolled out","more":0},{"t":20.1,"kind":"run","cmd":"kubectl -n shop get pods -l app=api; kubectl -n shop get endpoints api; kubectl -n shop logs deploy/api --tail=3; kubectl -n shop logs deploy/synthetic --since=60s | grep -vc \" 200$\"; kubectl -n shop logs deploy/synthetic --tail=3","out":"NAME                   READY   STATUS        RESTARTS   AGE\napi-7d77d48476-4cb7g   1/1     Running       0          2s\napi-7d77d48476-8485p   1/1     Running       0          1s\napi-7d87b9fcf5-94gkd   1/1     Terminating   0          104s\napi-7d87b9fcf5-m77ct   1/1     Terminating   0          104s\nWarning: v1 Endpoints is deprecated in v1.33+; use discovery.k8s.io/v1 EndpointSlice\nNAME   ENDPOINTS                             AGE\napi    10.244.0.173:8080,10.244.0.174:8080   104s\nFound 4 pods, using pod/api-7d87b9fcf5-94gkd\napi listening on 8080, db=db:5432\n0\n2026-11-03T05:37:19Z GET /orders 200\n2026-11-03T05:37:21Z GET /orders 200\n2026-11-03T05:37:23Z GET /orders 200","more":0},{"t":23.7,"kind":"run","cmd":"sleep 20; kubectl -n shop get pods; for p in $(kubectl -n shop get pods -l app=api -o name); do kubectl -n shop logs $p --tail=2; done; kubectl -n shop logs deploy/synthetic --since=90s | grep -v \" 200$\" | head; kubectl -n shop logs deploy/synthetic --tail=2","out":"NAME                         READY   STATUS        RESTARTS   AGE\napi-7d77d48476-4cb7g         1/1     Running       0          24s\napi-7d77d48476-8485p         1/1     Running       0          23s\napi-7d87b9fcf5-94gkd         1/1     Terminating   0          2m6s\napi-7d87b9fcf5-m77ct         1/1     Terminating   0          2m6s\ndb-5c45bf6fd6-9fl2g          1/1     Running       0          2m6s\nsynthetic-5cc5f987df-lzq6n   1/1     Running       0          2m6s\nweb-86cc98785b-8pdrj         1/1     Running       0          2m6s\nweb-86cc98785b-x7rkd         1/1     Running       0          2m6s\nworker-85767c58ff-wc5m5      1/1     Running       0          2m6s\napi listening on 8080, db=db:5432\napi listening on 8080, db=db:5432\napi listening on 8080, db=db:5432\napi listening on 8080, db=db:5432\n2026-11-03T05:37:45Z GET /orders 200\n2026-11-03T05:37:47Z GET /orders 200","more":0}],"report":"The crashing `api` pod is fixed. Someone renamed the `DB_HOST` key in the `api-config` ConfigMap to `DB_HOSTNAME`, so new pods exited at startup. I put the key back and restarted the rollout; both new `api` pods are running with no restarts, and the synthetic probe of `/orders` shows only 200s.\n\nThe two old `api` pods were still shutting down when I last looked, but they're no longer in the `api` endpoints so they don't receive traffic. The most likely reason is that Python, running as the container's main process, doesn't exit on the stop signal, so Kubernetes waits out the 30-second grace period before killing them.\n\nIMPACT: No customers were affected. The synthetic probe logged only 200s before and after the fix (none failed in the last 90s checked), because the two old `api` pods kept serving. From about 05:36:03Z (when revision 2's rollout started) the `api` rollout was stuck: pod `api-7bb64bd69b-9gvpk` restarted 3 times and the deployment was running on 2 old pods. The risk was that if either old pod restarted or was rescheduled, it would also have crashed and taken `/orders` down.\n\nROOT CAUSE: `ConfigMap/shop/api-config`, field `data.DB_HOST`. It had been renamed to `data.DB_HOSTNAME`, which differs from the last applied configuration (it still has `DB_HOST: db`). `api.py` requires `DB_HOST` and exits with `FATAL: DB_HOST is not set`. A restart started at 05:36:03Z (revision 2) made new pods read the changed ConfigMap. The old pods were only healthy because they had read their environment before the rename. Undoing the rollout would not have helped, because revisions 1 and 2 differ only in the restart annotation and both read the same ConfigMap.\n\nACTIONS TAKEN:\n1. Before changing anything, checked that only the `api` deployment uses `api-config` and that no code reads `DB_HOSTNAME`.\n2. Patched `ConfigMap/shop/api-config`: added `DB_HOST: db` and removed `DB_HOSTNAME`. Its data now matches the last applied configuration: `{\"DB_HOST\":\"db\",\"DB_PORT\":\"5432\"}`.\n3. `kubectl -n shop rollout restart deploy/api`. The rollout completed.\n\nSTATUS: Resolved.\n- New pods `api-7d77d48476-4cb7g` and `api-7d77d48476-8485p` are 1/1 Running with 0 restarts.\n- Their logs show `api listening on 8080, db=db:5432`.\n- The `api` endpoints point to the new pods (10.244.0.173 and .174).\n- In the 90s after the fix, the synthetic probe logged only `GET /orders 200`.\n- The crashlooping ReplicaSet was replaced.\n\nESCALATION: None. All changes were inside the `shop` namespace, and no data was at risk.\n\nFOLLOW-UP: Make the source-controlled manifests the only way `api-config` gets changed (the edit was made directly in the cluster, which is why the live ConfigMap no longer matched the last applied configuration). Also add a CI check that every environment variable `api.py` requires (`DB_HOST`, `DB_PORT`) exists in the ConfigMap. Optionally, make the deployment refer to a ConfigMap whose name includes a content hash, so a config change starts a new rollout immediately instead of waiting for the next restart."}