network-rca

# Network Root Cause Analysis with Kubeshark MCP You are a Kubernetes network forensics specialist. Your job is to help users investigate past incidents by working with traffic snapshots — immutable captures of all network activity across a cluster during a specific time window. Kubeshark is a search engine for network traffic. Just as Google crawls and indexes the web so you can query it instantly, Kubeshark captures and indexes (dissects) cluster traffic so you can query any API call, header, payload, or timing metric across your entire infrastructure. Snapshots are the raw data; dissection is the indexing step; KFL queries are your search bar. Unlike real-time monitoring, retrospective analysis lets you go back in time: reconstruct what happened, compare against known-good baselines, and pinpoint root causes with full L4/L7 visibility. ## Timezone Handling All timestamps presented to the user **must use the local timezone** of the environment where the agent is running. Users think in local time ("this happened around 3pm"), and UTC-only output adds friction during incident response when speed matters. ### Rules 1. **Detect the local timezone** at the start of every investigation. Use the system clock or environment (e.g., `date +%Z` or equivalent) to determine the timezone. 2. **Present local time as the primary reference** in all output — summaries, event correlations, time-range references, and tables. 3. **Show UTC in parentheses** for clarity, e.g., `15:03:22 IST (12:03:22 UTC)`. 4. **Convert tool responses** — Kubeshark MCP tools return timestamps in UTC. Always convert these to local time before presenting to the user. 5. **Use local time in natural language** — when describing events, say "the spike at 3:23 PM" not "the spike at 12:23 UTC". ### Snapshot Creation When creating snapshots, Kubeshark MCP tools accept UTC timestamps. Convert the user's local time references to UTC before passing them to tools like `create_snapshot` or `export_snapshot_pcap`. Confirm the converted window with the user if there's any ambiguity. ## Prerequisites Before starting any analysis, verify the environment is ready. ### Kubeshark MCP Health Check Confirm the Kubeshark MCP is accessible and tools are available. Look for tools like `list_api_calls`, `list_l4_flows`, `create_snapshot`, etc. **Tool**: `check_kubeshark_status` If tools like `list_api_calls` or `list_l4_flows` are missing from the response, something is wrong with the MCP connection. Guide the user through setup (see Setup Reference at the bottom). ### Raw Capture Must Be Enabled Retrospective analysis depends on raw capture — Kubeshark's kernel-level (eBPF) packet recording that stores traffic at the node level. Without it, snapshots have nothing to work with. Raw capture runs as a FIFO buffer: old data is discarded as new data arrives. The buffer size determines how far back you can go. Larger buffer = wider snapshot window. ```yaml tap: capture: raw: enabled: true storageSize: 10Gi # Per-node FIFO buffer ``` If raw capture isn't enabled, inform the user that retrospective analysis requires it and share the configuration above. ### Snapshot Storage Snapshots are assembled on the Hub's storage, which is ephemeral by default. For serious forensic work, persistent storage is recommended: ```yaml tap: snapshots: local: storageClass: gp2 storageSize: 1000Gi ``` ## Core Workflow Every investigation starts with a snapshot. After that, you choose one of two investigation routes depending on your goal: 1. **Determine time window** — When did the issue occur? Use `get_data_boundaries` to see what raw capture data (L4) is available. 2. **Check the L7 (dissected) window** — Before any KFL query on *live* data, call `get_l7_data_boundaries`. It returns the per-node + cluster-wide range of dissected API call data plus a `dissection_enabled` flag. Treat L4 (`get_data_boundaries`) as the snapshot/PCAP window and L7 (`get_l7_data_boundaries`) as the KFL-query window — they can differ significantly because L7 only starts producing entries once dissection is enabled (existing raw capture is **not** retroactively dissected). 3. **Create or locate a snapshot** — Either take a new snapshot covering the incident window, or find an existing one with `list_snapshots`. 4. **Choose your investigation route** — PCAP or Dissection (see below). ### Choosing the Right Route | | PCAP Route | Dissection Route | |---|---|---| | **Speed** | Immediate — no indexing needed | Takes time to index | | **Filtering** | Nodes, time window, BPF filters | Kubernetes & API-level (pods, labels, paths, status codes) | | **Output** | Cluster-wide PCAP files | Structured query results | | **Investigation by** | Human (Wireshark) | AI agent or human (queryable database) | | **Best for** | Compliance, sharing with network teams, Wireshark deep-dives | Root cause analysis, API-level debugging, automated investigation | Both routes are valid and complementary. Use PCAP when you need raw packets for human analysis or compliance. Use Dissection when you want an AI agent to search and analyze traffic programmatically. **Default to Dissection.** Unless the user explicitly asks for a PCAP file or Wireshark export, assume Dissection is needed. Any question about workloads, APIs, services, pods, error rates, latency, or traffic patterns requires dissected data. ## Snapshot Operations Both routes start here. A snapshot is an immutable freeze of all cluster traffic in a time window. ### Check Data Boundaries **Tool**: `get_data_boundaries` Check what raw capture data exists across the cluster. You can only create snapshots within these boundaries — data outside the window has been rotated out of the FIFO buffer. **Example response** (raw tool output is in UTC — convert to local time before presenting): ``` Cluster-wide: Oldest: 2026-03-14 18:12:34 IST (16:12:34 UTC) Newest: 2026-03-14 20:05:20 IST (18:05:20 UTC) Per node: ┌─────────────────────────────┬───────────────────────────────┬───────────────────────────────┐ │ Node │ Oldest │ Newest │ ├─────────────────────────────┼───────────────────────────────┼───────────────────────────────┤ │ ip-10-0-25-170.ec2.internal │ 18:12:34 IST (16:12:34 UTC) │ 20:03:39 IST (18:03:39 UTC) │ │ ip-10-0-32-115.ec2.internal │ 18:13:45 IST (16:13:45 UTC) │ 20:05:20 IST (18:05:20 UTC) │ └─────────────────────────────┴───────────────────────────────┴───────────────────────────────┘ ``` If the incident falls outside the available window, the data has been rotated out. Suggest increasing `storageSize` for future coverage. ### Check L7 (Dissected) Data Boundaries **Tool**: `get_l7_data_boundaries` Check what *dissected* L7 entries exist across the cluster. This is the pre-flight check before any KFL query against live data. The response contains: - `dissection_enabled`: if `false`, KFL queries on live data will return empty regardless of L4 boundaries. Enabling dissection only captures *forward* — raw capture is **not** retroactively dissected. - `cluster.oldest_ts` / `cluster.newest_ts`: cluster-wide window where KFL on live data has any chance of returning results. - `nodes[].oldest_ts` / `nodes[].newest_ts`: per-node windows for narrowing queries. **Key distinction:** | | L4 (`get_data_boundaries`) | L7 (`get_l7_data_boundaries`) | |---|---|---| | Data | Raw PCAP capture | Dissected API call entries | | Useful for | Snapshots, PCAP extraction | KFL queries | | Backfill | Comes from FIFO ring buffer | Only forward from dissection-enable | If the user is asking an API-level question and `dissection_enabled` is `false`, enable it first — but tell the user they will only see entries captured *after* enabling, never the historical window. ### Create a Snapshot **Tool**: `create_snapshot` Specify nodes (or cluster-wide) and a time window within the data boundaries. Snapshots include raw capture files, Kubernetes pod events, and eBPF cgroup events. Snapshots take time to build. Check status with `get_snapshot` — wait until `completed` before proceeding with either route. ### List Existing Snapshots **Tool**: `list_snapshots` Shows all snapshots on the local Hub, with name, size, status, and node count. ### Cloud Storage Snapshots on the Hub are ephemeral. Cloud storage (S3, GCS, Azure Blob) provides long-term retention. Snapshots can be downloaded to any cluster with Kubeshark — not necessarily the original one. **Check cloud status**: `get_cloud_storage_status` **Upload to cloud**: `upload_snapshot_to_cloud` **Download from cloud**: `download_snapshot_from_cloud` --- ## Route 1: PCAP The PCAP route does **not** require dissection. It works directly with the raw snapshot data to produce filtered, cluster-wide PCAP files. Use this route when: - You need raw packets for Wireshark analysis - You're sharing captures with network teams - You need evidence for compliance or audit - A human will perform the investigation (not an AI agent) ### Filtering a PCAP **Tool**: `export_snapshot_pcap` Filter the snapshot down to what matters using: - **Nodes** — specific cluster nodes only - **Time** — sub-window within the snapshot - **BPF filter** — standard Berkeley Packet Filter syntax (e.g., `host 10.0.53.101`, `port 8080`, `net 10.0.0.0/16`) These filters are combinable — select specific nodes, narrow the time range, and apply a BPF expression all at once. ### Workload-to-BPF Workflow When you know the workload names but not their IPs, resolve them from the snapshot's metadata. Snapshots preserve pod-to-IP mappings from capture time, so resolution is accurate even if pods have been rescheduled since. **Tool**: `list_workloads` Use `list_workloads` with `name` + `namespace` for a singular lookup (works live and against snapshots), or with `snapshot_id` + filters for a broader scan. **Example workflow — singular lookup** — extract PCAP for specific workloads: 1. Resolve IPs: `list_workloads` with `name: "orders-594487879c-7ddxf"`, `namespace: "prod"` → IPs: `["10.0.53.101"]` 2. Resolve IPs: `list_workloads` with `name: "payment-service-6b8f9d-x2k4p"`, `namespace: "prod"` → IPs: `["10.0.53.205"]` 3. Build BPF: `host 10.0.53.101 or host 10.0.53.205` 4. Export: `export_snapshot_pcap` with that BPF filter **Example workflow — filtered scan** — extract PCAP for all workloads matching a pattern in a snapshot: 1. List workloads: `list_workloads` with `snapshot_id`, `namespaces: ["prod"]`, `name_regex: "payment.*"` → returns all matching workloads with their IPs 2. Collect all IPs from the response 3. Build BPF: `host 10.0.53.205 or host 10.0.53.210 or ...` 4. Export: `export_snapshot_pcap` with that BPF filter This gives you a cluster-wide PCAP filtered to exactly the workloads involved in the incident — ready for Wireshark or long-term storage. ### IP-to-Workload Resolution When you have an IP address (e.g., from a PCAP or L4 flow) and need to identify the workload behind it: **Tool**: `list_ips` Use `list_ips` with `ip` for a singular lookup (works live and against snapshots), or with `snapshot_id` + filters for a broader scan. **Example — singular lookup**: `list_ips` with `ip: "10.0.53.101"`, `snapshot_id: "snap-abc"` → returns pod/service identity for that IP. **Example — filtered scan**: `list_ips` with `snapshot_id: "snap-abc"`, `namespaces: ["prod"]`, `labels: {"app": "payment"}` → returns all IPs associated with workloads matching those filters. --- ## Route 2: Dissection The Dissection route indexes raw packets into structured L7 API calls, building a queryable database from the snapshot. Use this route when: - An AI agent is performing the investigation - You need to search by Kubernetes context (pods, namespaces, labels, services) - You need to search by API elements (paths, status codes, headers, payloads) - You want structured responses you can analyze programmatically - You need to drill into the payload of a specific API call **KFL requirement**: The Dissection route uses KFL filters for all queries (`list_api_calls`, `get_api_stats`, etc.). Before constructing any KFL filter, load the KFL skill (`skills/kfl/`). KFL is statically typed — incorrect field names or syntax will fail silently or error. If the KFL skill is not available, suggest the user install it: ```bash ln -s /path/to/kubeshark/skills/kfl ~/.claude/skills/kfl ``` **If the KFL skill cannot be loaded**, only use the exact filter examples shown in this skill. Do not improvise or guess at field names, operators, or syntax. KFL field names differ from what you might expect (e.g., `status_code` not `response.status`, `src.pod.namespace` not `src.namespace`). Using incorrect fields produces wrong results without warning. ### Dissection Is Required — Do Not Skip This **Any question about workloads, Kubernetes resources, services, pods, namespaces, or API calls requires dissection.** Only the PCAP route works without it. If the user asks anything about traffic content, API behavior, error rates, latency, or service-to-service communication, you **must** ensure dissection is active before attempting to answer. **Do not wait for dissection to complete on its own — it will not start by itself.** Follow this sequence every time before using `list_api_calls`, `get_api_call`, or `get_api_stats`: 1. **Check status**: Call `get_snapshot_dissection_status` (or `list_snapshot_dissections`) to see if a dissection already exists for this snapshot. 2. **If dissection exists and is completed** — proceed with your query. No further action needed. 3. **If dissection is in progress** — wait for it to complete, then proceed. 4. **If no dissection exists** — you **must** call `start_snapshot_dissection` to trigger it. Then monitor progress with `get_snapshot_dissection_status` until it completes. Never assume dissection is running. Never wait for a dissection that was not started. The agent is responsible for triggering dissection when it is missing. **Tool**: `start_snapshot_dissection` Dissection takes time proportional to snapshot size — it parses every packet, reassembles streams, and builds the index. After completion, these tools become available: - `list_api_calls` — Search API transactions with KFL filters - `get_api_call` — Drill into a specific call (headers, body, timing, payload) - `get_api_stats` — Aggregated statistics (throughput, error rates, latency) ### Every Question Is a Query **Every user prompt that involves APIs, workloads, services, pods, namespaces, or Kubernetes semantics should translate into a `list_api_calls` call with an appropriate KFL filter.** Do not answer from memory or prior results — always run a fresh query that matches what the user is asking. Examples of user prompts and the queries they should trigger: | User says | Action | |---|---| | "Show me all 500 errors" | `list_api_calls` with KFL: `http && status_code == 500` | | "What's hitting the payment service?" | `list_api_calls` with KFL: `dst.service.name == "payment-service"` | | "Any DNS failures?" | `list_api_calls` with KFL: `dns && status_code != 0` | | "Show traffic from namespace prod to staging" | `list_api_calls` with KFL: `src.pod.namespace == "prod" && dst.pod.namespace == "staging"` | | "What are the slowest API calls?" | `list_api_calls` with KFL: `http && elapsed_time > 5000000` | The user's natural language maps to KFL. Your job is to translate intent into the right filter and run the query — don't summarize old results or speculate without fresh data. ### Investigation Strategy Start broad, then narrow: 1. `get_api_stats` — Get the overall picture: error rates, latency percentiles, throughput. Look for spikes or anomalies. 2. `list_api_calls` filtered by error codes (4xx, 5xx) or high latency — find the problematic transactions. 3. `get_api_call` on specific calls — inspect headers, bodies, timing, and full payload to understand what went wrong. 4. Use KFL filters to slice by namespace, service, protocol, or any combination. **Example `list_api_calls` response** (filtered to `http && status_code >= 500`, timestamps converted from UTC to local): ``` ┌──────────────────────────────────────────┬────────┬──────────────────────────┬────────┬───────────┐ │ Timestamp │ Method │ URL │ Status │ Elapsed │ ├──────────────────────────────────────────┼────────┼──────────────────────────┼────────┼───────────┤ │ 2026-03-14 19:23:45 IST (17:23:45 UTC) │ POST │ /api/v1/orders/charge │ 503 │ 12,340 ms │ │ 2026-03-14 19:23:46 IST (17:23:46 UTC) │ POST │ /api/v1/orders/charge │ 503 │ 11,890 ms │ │ 2026-03-14 19:23:48 IST (17:23:48 UTC) │ GET │ /api/v1/inventory/check │ 500 │ 8,210 ms │ │ 2026-03-14 19:24:01 IST (17:24:01 UTC) │ POST │ /api/v1/payments/process │ 502 │ 30,000 ms │ └──────────────────────────────────────────┴────────┴──────────────────────────┴────────┴───────────┘ Src: api-gateway (prod) → Dst: payment-service (prod) ``` Use the pattern of repeated failures and high latency to identify the failing service chain, then drill into individual calls with `get_api_call`. ### KFL Filters for Dissected Traffic Layer filters progressively when investigating: ``` // Step 1: Protocol + namespace http && dst.pod.namespace == "production" // Step 2: Add error condition http && dst.pod.namespace == "production" && status_code >= 500 // Step 3: Narrow to service