DEX - Docker EXporter for prometheus

DEX is a lightweight Prometheus exporter that monitors Docker containers and exports their metrics. It's designed to run as a Docker container and supports all architectures.

Key Features

• Lightweight and efficient
• Supports all architectures
• Real-time container metrics monitoring
• Easy integration with Prometheus and Grafana
• No configuration required for basic usage

Exposed Metrics

Metric Name	Type	Description	Labels
dex_block_io_read_bytes_total	Counter	Total number of bytes read from block devices	container_name
dex_block_io_write_bytes_total	Counter	Total number of bytes written to block devices	container_name
dex_container_exited	Gauge	1 if container has exited, 0 otherwise	container_name
dex_container_restarting	Gauge	1 if container is restarting, 0 otherwise	container_name
dex_container_restarts_total	Counter	Total number of container restarts	container_name
dex_container_running	Gauge	1 if container is running, 0 otherwise	container_name
dex_cpu_utilization_percent	Gauge	Current CPU utilization percentage	container_name
dex_cpu_utilization_seconds_total	Counter	Cumulative CPU time consumed	container_name
dex_memory_total_bytes	Gauge	Total memory limit in bytes	container_name
dex_memory_usage_bytes	Counter	Current memory usage in bytes	container_name
dex_memory_utilization_percent	Gauge	Current memory utilization percentage	container_name
dex_network_rx_bytes_total	Counter	Total bytes received over network	container_name
dex_network_tx_bytes_total	Counter	Total bytes transmitted over network	container_name
dex_pids_current	Counter	Current number of processes in the container	container_name

Prerequisites

• Docker installed and running
• Prometheus server (for metrics collection)
• Grafana (optional, for visualization)

Configuration

Environment Variable	Description	Default
DEX_PORT	The port the exporter will listen on.	8080
DEX_LABELS	Comma-separated list of additional labels to export.	""

Dynamic Labels

You can add extra labels to all metrics using the DEX_LABELS environment variable. This can be useful for adding more context to your metrics, such as the image name or command.

Available Labels:

• image
• image_id
• command
• created

Example:

export DEX_LABELS="image,command"

This will add the image and command labels to all exported metrics.

Warning

NOTE! High Cardinality Ahead!

Each unique combination of key-value label pairs represents a new time series in Prometheus. Using labels with high cardinality (many different values), such as image_id or created, can dramatically increase the amount of data stored and impact Prometheus' performance.

For more information, please see the Prometheus documentation on labels.

Run with docker

Start docker container with following docker-compose.yml:

version: '2.1'
services:
   dex:
      image: spx01/dex
      container_name: dex
      volumes:
         - /var/run/docker.sock:/var/run/docker.sock
      ports:
         - 8386:8080
      restart: always

Building from Source

As an alternative to Docker, you can build and run DEX from source:

# Clone the repository
git clone https://github.com/spx01/dex.git
cd dex

# Build the binary
go build -o dex .

# Run the exporter
./dex

Test with curl

$ curl localhost:8386/metrics

Example output:

# HELP dex_container_running 1 if docker container is running, 0 otherwise
# TYPE dex_container_running gauge
dex_container_running{container_name="dex"} 1
# HELP dex_cpu_utilization_percent CPU utilization in percent
# TYPE dex_cpu_utilization_percent gauge
dex_cpu_utilization_percent{container_name="dex"} 0.036
...

Contributing

Contributions are welcome! Please feel free to submit a pull request.

Grafana dashboard

Grafana 7

Example grafana7 dashboard definition as JSON .

Grafana 8

Another dashboard for Grafana 8 (thanks @scMarkus !!!) as JSON

Modification (thanks @GitSchorsch) with additional job filter as JSON