PDU Exporter

The PDU Exporter is a lightweight custom Prometheus exporter designed to collect metrics from Power Distribution Unit (PDU) devices that expose raw status data via the /status.cgi endpoint over HTTP, transforming this data into Prometheus-compatible metrics.

Features

• Connects directly to the PDU via raw TCP (port 80)
• Sends a manual HTTP GET request
• Supports basic authentication
• Exposes metrics such as current, voltage, power, energy, temperature, humidity, and sensor existence
• Dockerized for easy deployment

Exported Metrics

Metric Name	Description	Labels
current	Current in Amperes	address
voltage	Voltage in Volts	address
power	Power in Watts	address
power_factor	Power factor (0.0 to 1.0)	address
energy	Energy in kilowatt-hours	address
temperature	Temperature in Celsius	address, channel
humidity	Humidity in percent	address, channel
sensor_exists	Sensor existence (1.0 or 0.0)	type

API Endpoints

/-/reload

Method: POST, PUT Description: Reloads the configuration without restarting the process.

Example:

POST /-/reload
PUT /-/reload

You can also reload configuration by sending the SIGHUP signal to the pdu_exporter process ID using the command below:

kill -s SIGHUP $(pidof pdu_exporter)

/pdu

Method: GET Query Parameters:

• target: IP address or hostname of the PDU.

Example:

GET /pdu?target=192.168.1.1

/api/rack-names

Method: GET Description: Returns a list of rack names extracted from each PDU address block.

Query Parameters:

• target: IP address or hostname of the PDU.

Example:

GET /api/rack-names?target=192.168.1.1

Example Response (JSON):

{
  "rack_names": {
    "rack_1": "# 1 Rack A",
    "rack_2": "# 2 Rack B",
    ...
    "rack_32": "# 32 Rack AF"
  }
}

Prometheus Integration

Sample Scrape Config:

scrape_configs:
  - job_name: 'pdu'
    metrics_path: /pdu
    static_configs:
      - targets:
        - 192.168.1.1
    relabel_configs:
      - source_labels: [__address__]
        target_label: __param_target
      - source_labels: [__param_target]
        target_label: instance
      - target_label: __address__
        replacement: 127.0.0.1:9117 # Address of the PDU Exporter container or host
    basic_auth: # Sets the `Authorization` header on every request
      username: user # Configured username
      password: pass # Configured password

PDU Exporter Configuration

Example pdu_exporter.yaml

# How long until a scrape request times out.
scrape_configs:
  scrape_timeout: 5s

# Usernames and hashed passwords that have full access to the web server via basic authentication.
# If empty, no basic authentication is required. Passwords are hashed with bcrypt.
basic_auth_users:
  user: $2a$12$eId/v3HxJFjZWCkeTV/.VeUg5Qie66aPumgGlzELcy2ndCxpo5fV6
  rlggyp: $2a$12$fKG1d9B5d7JDa78s7XBHDu/YD.46VK.t3W8BnujOwErrNCvRB9vsS

Example log4rs.yaml

refresh_rate: 30 seconds

appenders:
  rolling_file:
    kind: rolling_file
    path: "/etc/pdu_exporter/logs/app.log"
    policy:
      kind: compound
      trigger:
        kind: size
        limit: 1 mb
      roller:
        kind: fixed_window
        pattern: "/etc/pdu_exporter/logs/app-{}.log"
        base: 1
        count: 7
    encoder:
      pattern: "{d(%Y-%m-%d %H:%M:%S)} [{l}] {t} - {m}{n}"

root:
  level: info
  appenders:
    - rolling_file

Docker Usage

Docker Compose Example

Below is a sample docker-compose.yaml:

services:
  pdu_exporter:
    image: rlggyp/pdu_exporter:latest
    container_name: pdu_exporter
    user: 1000:1000
    pull_policy: always
    environment:
      - CONFIG_FILE=/etc/pdu_exporter/configs/pdu_exporter.yaml
      - LOG_CONFIG_FILE=/etc/pdu_exporter/configs/log4rs.yaml
    ports:
      - 9117:9117
    volumes:
      - ./configs:/etc/pdu_exporter/configs
      - ./logs:/etc/pdu_exporter/logs
    restart: unless-stopped

Directory structure example:

.
├── configs
│   ├── pdu_exporter.yaml
│   └── log4rs.yaml
├── logs
└── docker-compose.yaml

• Place your pdu_exporter.yaml and log4rs.yaml in the configs directory.
• Logs will be written to the logs directory.

---

Running with Docker Compose

You have two options to run the PDU Exporter:

Option 1: Build the Docker Image Locally

1. Build the image:

   docker build -t pdu_exporter:latest .

2. Edit your docker-compose.yaml and change the image line to use your local image:

   image: pdu_exporter:latest

3. Start the service:

   docker compose up -d

Option 2: Use the Prebuilt Image from Docker Hub

No need to build anything. Just use the provided docker-compose.yaml (with image: rlggyp/pdu_exporter:latest) and run:

docker compose up -d

Error Handling

• Returns 400 Bad Request if target is missing.
• Returns 401 Unauthorized if authentication fails.
• Returns 404 Not Found if the TCP connection to the PDU fails.
• Returns 408 Request Timeout if the connection to target times out.
• Returns 422 Unprocessable Entity if the response structure is invalid.
• Returns 500 Internal Server Error for I/O or parsing errors.

Limitations

• Assumes the PDU /status.cgi response contains exactly 2016 elements.
• Metrics parsing is tightly coupled with this structure.
• Only supports plain TCP and HTTP (no TLS, no SNMP).

License

This project is licensed under the MIT License. See the LICENSE file for details.