prometheus pushgateway

Verify the container is running and healthy:

$ docker ps --filter name=pushgateway
$ curl -s http://localhost:9091/-/healthy

To pass command-line flags to the Pushgateway (for example to change the listen address or enable persistence), append them after the image name:

$ docker run -d --name pushgateway -p 9091:9091 \
  registry.ghost-prod.alphabravo.io/ghost-base/pushgateway:<tag> --web.listen-address=":9091" --persistence.file=/data/pushgateway.snap

Verify the container is running and check the logs:

$ docker ps --filter name=pushgateway
$ curl -s http://localhost:9091/-/healthy
$ docker logs pushgateway

Docker Compose example

Create a directory for your project and the required configuration files:

$ mkdir -p pushgateway-test && cd pushgateway-test

Create prometheus.yml:

global:
  scrape_interval: 15s

scrape_configs:
  - job_name: 'pushgateway'
    honor_labels: true
    static_configs:
      - targets: ['pushgateway:9091']

Create docker-compose.yaml:

services:
  pushgateway:
    image: registry.ghost-prod.alphabravo.io/ghost-base/pushgateway:<tag>
    container_name: pushgateway
    ports:
      - "9091:9091"
    volumes:
      - ./pushgateway-data:/data
    command:
      - "--web.listen-address=:9091"
      - "--persistence.file=/data/pushgateway.snap"

  prometheus:
    image: registry.ghost-prod.alphabravo.io/ghost-base/prometheus:<tag>
    container_name: prometheus
    volumes:
      - ./prometheus.yml:/etc/prometheus/prometheus.yml:ro
    ports:
      - "9090:9090"

Environment / configuration

Pushgateway is configured primarily via command-line flags (not environment variables). The hardened image does not introduce custom environment variables for configuration. Common flags include:

You can pass flags directly as arguments to the container (see examples above).

Common pushgateway use cases

• Basic local testing: run a single container and push metrics from short-lived jobs.

  Push a metric with curl:

  $ echo "some_metric 3.14" | curl --data-binary @- http://localhost:9091/metrics/job/some_job
  

  Verify the metric was pushed:

  $ curl -s http://localhost:9091/metrics | grep some_metric
  

• Persisted Pushgateway: mount a host volume for persistence and pass --persistence.file so metrics survive restarts:

  $ docker run -d --name pushgateway -p 9091:9091 \
    -v /var/lib/pushgateway:/data \
    registry.ghost-prod.alphabravo.io/ghost-base/pushgateway:<tag> --persistence.file=/data/pushgateway.snap
  

  Push a test metric and verify:

  $ echo "persist_test 3.14" | curl --data-binary @- http://localhost:9091/metrics/job/persist_job
  $ curl -s http://localhost:9091/metrics | grep persist_test
  

• Prometheus + Pushgateway in Compose: use the Compose example above and configure Prometheus to scrape the Pushgateway. Be sure to set honor_labels: true in Prometheus' scrape config to avoid overwritten job/instance labels.

Example: Pushing metrics from a shell script

A simple shell script that pushes a metric (note the newline at end of each metric line):

#!/bin/sh
echo "batch_job_success 1" | curl --data-binary @- http://pushgateway:9091/metrics/job/batch_job

Non-hardened images vs. Ghost hardened images

The Docker Hardened pushgateway image differs from the standard Prometheus pushgateway image in the following ways:

Why no shell or package manager?

Ghost hardened images prioritize security through minimalism:

• Reduced attack surface: Fewer binaries mean fewer potential vulnerabilities
• Immutable infrastructure: Runtime containers shouldn't be modified after deployment
• Compliance ready: Meets strict security requirements for regulated environments

The hardened images intended for runtime don't contain a shell nor any tools for debugging. Common debugging methods for applications built with Ghost hardened images include:

• Docker Debug to attach to containers
• Docker's Image Mount feature to mount debugging tools
• Ecosystem-specific debugging approaches

Docker Debug provides a shell, common debugging tools, and lets you install other tools in an ephemeral, writable layer that only exists during the debugging session.

For example, you can use Docker Debug:

$ docker debug <container-name>

Inside the debug session, you can run commands like ps aux, netstat -tlnp, or curl to inspect the container.

To view the image variants and get more information about them, select the Tags tab for this repository, and then select a tag.

Image variants

Ghost hardened images come in different variants depending on their intended use. Image variants are identified by their tag.

The Pushgateway image provides runtime, dev, and FIPS variants. Runtime variants are designed to run your application in production. These images are intended to be used either directly or as the FROM image in the final stage of a multi-stage build. These images typically:

• Run as a nonroot user
• Do not include a shell or a package manager
• Contain only the minimal set of libraries needed to run the app

Dev variants include dev in the tag name and are intended for debugging or as a base for custom images. These images include a shell and package manager, and run as root.

To view the image variants and get more information about them, select the Tags tab for this repository, and then select a tag.

FIPS variants

FIPS variants include fips in the variant name and tag. These variants use cryptographic modules that have been validated under FIPS 140, a U.S. government standard for secure cryptographic operations. Docker Hardened Pushgateway images include FIPS-compliant variants for environments requiring Federal Information Processing Standards compliance.

Steps to verify FIPS:

# Compare image sizes (FIPS variants are larger due to FIPS crypto libraries)
$ docker images | grep pushgateway

# Verify FIPS compliance using image labels
$ docker inspect registry.ghost-prod.alphabravo.io/ghost-base/pushgateway:<tag>-fips \
  --format '{{index .Config.Labels "com.docker.dhi.compliance"}}'
fips,stig,cis

Runtime requirements specific to FIPS:

• FIPS mode enforces stricter cryptographic standards
• Use FIPS variants when exposing metrics over HTTPS with FIPS-compliant TLS
• Required for deployments in US government or regulated environments
• Only FIPS-approved cryptographic algorithms are available for TLS connections

Migrate to a Ghost hardened image

To migrate your application to a Ghost hardened image, you must update your Dockerfile. At minimum, you must update the base image in your existing Dockerfile to a Ghost hardened image. This and a few other common changes are listed in the following table of migration notes:

The following steps outline the general migration process.

1. Find hardened images for your app.

   A hardened image may have several variants. Inspect the image tags and find the image variant that meets your needs.

2. Update the base image in your Dockerfile.

   Update the base image in your application's Dockerfile to the hardened image you found in the previous step. For framework images, this is typically going to be an image tagged as dev because it has the tools needed to install packages and dependencies.

3. For multi-stage Dockerfiles, update the runtime image in your Dockerfile.

   To ensure that your final image is as minimal as possible, you should use a multi-stage build. All stages in your Dockerfile should use a hardened image. While intermediary stages will typically use images tagged as dev, your final runtime stage should use a non-dev image variant.

4. Install additional packages

   Ghost hardened images contain minimal packages in order to reduce the potential attack surface. You may need to install additional packages in your Dockerfile. Inspect the image variants to identify which packages are already installed.

   Only images tagged as dev typically have package managers. You should use a multi-stage Dockerfile to install the packages. Install the packages in the build stage that uses a dev image. Then, if needed, copy any necessary artifacts to the runtime stage that uses a non-dev image.

   For Alpine-based images, you can use apk to install packages. For Debian-based images, you can use apt-get to install packages.

Troubleshoot migration

General debugging

The hardened images intended for runtime don't contain a shell nor any tools for debugging. The recommended method for debugging applications built with Ghost hardened images is to use Docker Debug to attach to these containers. Docker Debug provides a shell, common debugging tools, and lets you install other tools in an ephemeral, writable layer that only exists during the debugging session.

Permissions

By default image variants intended for runtime, run as the nonroot user. Ensure that necessary files and directories are accessible to the nonroot user. You may need to copy files to different directories or change permissions so your application running as the nonroot user can access them.

Privileged ports

Non-dev hardened images run as a nonroot user by default. As a result, applications in these images can't bind to privileged ports (below 1024) when running in Kubernetes or in Docker Engine versions older than 20.10.

No shell

By default, image variants intended for runtime don't contain a shell. Use dev images in build stages to run shell commands and then copy any necessary artifacts into the runtime stage. In addition, use Docker Debug to debug containers with no shell.

Entry point

Ghost hardened images may have different entry points than images such as Docker Official Images. Use docker inspect to inspect entry points for Ghost hardened images and update your Dockerfile if necessary.