Imported from huaweicloud/huaweicloud-skills (skills/content&edge/cdn/huawei-cloud-cdn-traffic-anomaly-analysis/SKILL.md). Install upstream with npx skills add huaweicloud/huaweicloud-skills --skill huawei-cloud-cdn-traffic-anomaly-analysis. Copyright stays with the author.

CDN Traffic Anomaly Analysis

Overview

This skill analyzes CDN domain traffic anomalies by querying billing mode and corresponding traffic/bandwidth metrics. It automatically determines the appropriate metric based on the account's billing mode (bw_95, flux, combine_flux, bw, bw_peak), queries historical data over a configurable time range, establishes a 3-month baseline for comparison, and identifies potential traffic theft or abuse using both absolute thresholds and relative baseline deviation.

Key Features:

• Automatic billing mode detection and metric selection
• Support for all billing modes: bw_95, flux, combine_flux, bw, bw_peak
• Domain validation and traffic analysis
• 3-month baseline analysis — detects relative traffic surges against historical norms
• Dual-threshold anomaly detection — absolute thresholds + relative baseline comparison
• Three-tier conclusions: Normal / Watch (relative surge) / Anomalous (absolute threshold exceeded)
• Comprehensive analysis reports with baseline comparison and daily breakdowns

Tool: hcloud CLI (KooCLI)
Timestamp Tool: scripts/cdn_timestamp.py (built-in)
Analysis Scope: Past 7 days for current window (configurable); past 3 months for baseline
Core Principle: Query only the metric corresponding to the billing mode; use API capabilities efficiently to cover both current and baseline windows with minimal API calls

⛔ Prohibited Operations (Security Constraints)

This skill strictly forbids the following operations, regardless of user requests:

If a user requests a prohibited operation, you must refuse and inform: "Per security constraints, this skill does not allow write/delete operations. This skill is read-only for traffic analysis. Please use the Huawei Cloud CDN console or hcloud CLI manually for configuration changes."

Architecture

CDN Traffic Anomaly Analysis
├── ShowChargeModes        (Query account billing mode)
├── ListDomains/v2         (List all CDN domains)
├── Domain Validation      (Verify target domain exists)
├── TimestampCalculation   (scripts/cdn_timestamp.py)
│   ├── Current window     (default 7 days, UTC+8 midnight)
│   └── Baseline windows   (3 × 30-day windows, non-overlapping)
├── QueryMetrics           (Based on billing mode)
│   ├── bw_95 → ShowBandwidthCalc
│   │   ├── Current: 1 call (7-day single aggregate)
│   │   └── Baseline: 3 calls (30-day aggregates each)
│   └── flux/bw → ShowDomainStats/v2 (stat_type=flux or bw)
│       └── Combined: 1 call (97 days → 90d baseline + 7d current)
└── ThresholdJudgment      (Dual-threshold: absolute + baseline-relative)
    ├── ⚠️ Anomalous: exceeds absolute threshold
    ├── 👀 Watch: exceeds baseline × multiplier (sub-threshold surge)
    └── ✅ Normal: neither threshold triggered

API Call Budget

KooCLI Command Format Standard

All hcloud CDN commands follow this standard format:

hcloud CDN <Operation> --cli-region=cn-north-4 [--parameter=value ...]

Format Rules:

• Service name: CDN (uppercase)
• Operation name: PascalCase (e.g., ShowChargeModes, ListDomains, ShowBandwidthCalc)
• Region parameter: --cli-region=cn-north-4 (required, always use cn-north-4 for CDN)
• Parameter format: --key=value (equals sign, no space)
• Indexed parameters: --key.1=value1 (for array parameters)

Examples:

# Correct
hcloud CDN ShowChargeModes --cli-region=cn-north-4 --product_type=base
hcloud CDN ListDomains/v2 --cli-region=cn-north-4 --page_size=100

# Incorrect (space instead of equals sign)
hcloud CDN ShowChargeModes --cli-region cn-north-4

Prerequisites

Prerequisite check: Huawei Cloud CLI (hcloud / KooCLI) >= 3.2.0 required Run hcloud version to verify version >= 3.2.0. If not installed or version is too low, see references/cli-installation-guide.md for installation guide.

hcloud version

Prerequisite check: Python >= 3.8 required (for timestamp calculation) Run python --version to verify version >= 3.8.

python --version

Prerequisite check: hcloud credentials configured

Before performing CDN operations, you must verify hcloud credentials are configured:

hcloud configure list

If no valid credentials exist, stop and guide the user to configure credentials.

⚠️ hcloud parameter format requirements

hcloud (KooCLI) all parameters must use the --param=value format (connected with equals sign); space-separated format is not supported.

✅ Correct: hcloud CDN ShowChargeModes --cli-region=cn-north-4

❌ Incorrect: hcloud CDN ShowChargeModes --cli-region cn-north-4

⚠️ CDN API region requirements

CDN APIs support multiple regions. It is recommended to use cn-north-4, but the APIs are not limited to this region only. Query results are region-independent (CDN is a global service). Recommended: Always use cn-north-4.

Authentication

Prerequisite check: Huawei Cloud credentials required

Security rules (must be followed):

• Prohibited from reading, echoing, or printing AK/SK values
• Prohibited from asking the user to input AK/SK directly in the conversation
• Prohibited from using hcloud configure set to pass plaintext credential values
• Prohibited from accepting AK/SK directly provided by the user in the conversation
• Only allowed to read credentials from environment variables or configured CLI config files

⚠️ Important: Handling user-provided credentials

If a user attempts to provide AK/SK directly (e.g., "my AK is xxx, SK is yyy"):

1. Stop immediately - Do not execute any commands
2. Politely refuse and return the following message:

   For account security, please do not provide Huawei Cloud Access Key ID and Access Key Secret directly in the conversation.
   
   Please use one of the following secure methods to configure credentials:
   
   Method 1: Interactive configuration (recommended)
       hcloud configure
       # Enter AK/SK as prompted; credentials will be securely stored in a local config file
   
   Method 2: Environment variable configuration
       export HUAWEICLOUD_SDK_AK=<your-access-key-id>
       export HUAWEICLOUD_SDK_SK=<your-secret-key>
   
   After configuration is complete, please retry your request.
   

3. Do not continue executing any Huawei Cloud operations until credentials are configured

Check CLI configuration:

   hcloud configure list

Check whether the output contains valid configuration (AK/SK, IAM, etc.).

If no valid credentials exist, stop here.

IAM Permission Policies

Ensure the IAM user has the required permissions. See references/iam-policies.md for details.

Minimum required permissions:

• cdn:domain:list — List CDN domains
• cdn:domain:get — Get domain details
• cdn:statistics:get — Get traffic/bandwidth statistics
• cdn:billing:get — Get billing mode information

Core Commands

Quick reference for all hcloud CDN commands used in this skill:

Notes:

• All commands require --cli-region=cn-north-4
• Timestamps must be in milliseconds (e.g., 1785081600000)
• Use scripts/cdn_timestamp.py to calculate timestamps
• Use scripts/cdn_timestamp.py --baseline for 3×30-day baseline windows
• ShowBandwidthCalc: max 31-day range, single aggregate value (no per-day breakdown), rate limit 2 calls/s
• ShowDomainStats/v2: supports ≥365-day range, one data point per day at interval=86400, rate limit 15 calls/s

Parameter Confirmation

Before executing the analysis, confirm the following parameters with the user:

User Confirmation Checklist:

• Target domain name provided or selected from domain list
• Analysis time range confirmed (default: past 7 days for current window)
• User understands this is a read-only analysis operation
• User understands the baseline comparison spans past 3 months

Core Workflows

Step 1: Query Account Billing Mode

Query billing mode via hcloud CLI to determine which metric to analyze.

📄 Detailed steps → references/task-show-charge-modes.md

Step 2: List All CDN Domains

Get all online CDN domains under the current account.

If the user did not provide a domain, or the provided domain is not in the list, you must list all available domains for the user to choose from.

📄 Detailed steps → references/task-list-domains.md

Step 3: Domain Validation

Verify the user-provided domain exists in the domain list.

📄 Detailed steps → references/task-domain-validation.md

Step 4: Timestamp Calculation

Calculate time range for the current window (default 7 days) and 3 baseline windows (30 days each, non-overlapping), aligned to UTC+8 midnight.

📄 Detailed steps → references/task-timestamp-calculation.md

Step 5: Query Current Window Metrics

Query the corresponding metric for the current window (7 days) based on billing mode.

📄 Detailed steps → references/task-query-metrics.md

Step 6: Query Baseline Metrics

Query the corresponding metric for the baseline window (past 3 months) based on billing mode.

• bw_95: 3 separate calls to ShowBandwidthCalc, each covering one non-overlapping 30-day window (API max range is 31 days). Sleep 0.6s between calls to respect the 2 calls/s rate limit.
• flux / bw: The same ShowDomainStats/v2 call from Step 5 covers both current and baseline windows (97 days total). Split the first 90 daily values as baseline, last 7 as current window.

📄 Detailed steps → references/task-query-metrics.md

Step 7: Threshold Judgment

Apply dual-threshold logic: absolute thresholds (hard limits) + relative baseline comparison (surge detection). Generate a three-tier analysis report.

📄 Detailed steps → references/task-threshold-judgment.md

Threshold Rules Summary

Three-tier conclusion:

• ⚠️ Anomalous — Absolute threshold exceeded; strong signal of traffic theft
• 👀 Watch — Does not exceed absolute threshold, but exceeds baseline × 1.5; potential relative surge worth investigating
• ✅ Normal — Falls within both absolute and relative thresholds

No-data domains (result: {} or value: 0) are always treated as Normal.

References