kafka exporter

cat <<EOF > docker-compose.yml
services:
  kafka-exporter:
    image: registry.ghost-prod.alphabravo.io/ghost-base/kafka-exporter:<tag>
    command: ["--kafka.server=kafka:9092"]
    ports:
      - 9308:9308
EOF

Run with Docker Compose

To test Kafka Exporter with a running Kafka broker, use this complete Docker Compose configuration:

cat <<EOF > docker-compose.yml
services:
  kafka:
    image: registry.ghost-prod.alphabravo.io/ghost-base/kafka:<tag>
    container_name: kafka
    ports:
      - "9092:9092"
    environment:
      KAFKA_NODE_ID: 1
      KAFKA_PROCESS_ROLES: broker,controller
      KAFKA_LISTENERS: PLAINTEXT://:9092,CONTROLLER://:9093
      KAFKA_ADVERTISED_LISTENERS: PLAINTEXT://kafka:9092
      KAFKA_CONTROLLER_LISTENER_NAMES: CONTROLLER
      KAFKA_CONTROLLER_QUORUM_VOTERS: 1@localhost:9093
      KAFKA_OFFSETS_TOPIC_REPLICATION_FACTOR: 1

  kafka-exporter:
    image: registry.ghost-prod.alphabravo.io/ghost-base/kafka-exporter:<tag>
    command: ["--kafka.server=kafka:9092"]
    ports:
      - "9308:9308"
    depends_on:
      - kafka
    restart: on-failure
EOF

Start the stack:

$ docker compose up -d

Wait approximately 30 seconds for Kafka to initialize, then verify the metrics endpoint:

$ curl http://localhost:9308/metrics | grep kafka_brokers
# HELP kafka_brokers Number of Brokers in the Kafka Cluster.
# TYPE kafka_brokers gauge
kafka_brokers 1

Use Kafka Exporter in Kubernetes

To use the Kafka Exporter hardened image in Kubernetes, set up authentication and update your Kubernetes deployment.

cat <<EOF > kafka-exporter.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: kafka-exporter
  namespace: default
spec:
  replicas: 1
  selector:
    matchLabels:
      app: kafka-exporter
  template:
    metadata:
      labels:
        app: kafka-exporter
    spec:
      containers:
        - name: kafka-exporter
          image: registry.ghost-prod.alphabravo.io/ghost-base/kafka-exporter:<tag>
          args:
            - --kafka.server=kafka:9092
          ports:
          - containerPort: 9308
            name: metrics
      imagePullSecrets:
        - name: <your-registry-secret>
EOF

Then apply the manifest to your Kubernetes cluster:

$ kubectl apply -n default -f kafka-exporter.yaml

Full Stack Kubernetes Deployment

To deploy both Kafka and Kafka Exporter in Kubernetes:

cat <<EOF > kafka.yaml
apiVersion: v1
kind: Service
metadata:
  name: kafka
  namespace: default
spec:
  ports:
    - port: 9092
      targetPort: 9092
  selector:
    app: kafka
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: kafka
  namespace: default
spec:
  replicas: 1
  selector:
    matchLabels:
      app: kafka
  template:
    metadata:
      labels:
        app: kafka
    spec:
      containers:
        - name: kafka
          image: registry.ghost-prod.alphabravo.io/ghost-base/kafka:<tag>
          ports:
            - containerPort: 9092
            - containerPort: 9093
          env:
            - name: KAFKA_NODE_ID
              value: "1"
            - name: KAFKA_PROCESS_ROLES
              value: "broker,controller"
            - name: KAFKA_LISTENERS
              value: "PLAINTEXT://:9092,CONTROLLER://:9093"
            - name: KAFKA_ADVERTISED_LISTENERS
              value: "PLAINTEXT://kafka:9092"
            - name: KAFKA_CONTROLLER_LISTENER_NAMES
              value: "CONTROLLER"
            - name: KAFKA_CONTROLLER_QUORUM_VOTERS
              value: "1@localhost:9093"
            - name: KAFKA_OFFSETS_TOPIC_REPLICATION_FACTOR
              value: "1"
      imagePullSecrets:
        - name: <your-registry-secret>
EOF

cat <<EOF > kafka-exporter.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: kafka-exporter
  namespace: default
spec:
  replicas: 1
  selector:
    matchLabels:
      app: kafka-exporter
  template:
    metadata:
      labels:
        app: kafka-exporter
    spec:
      containers:
        - name: kafka-exporter
          image: registry.ghost-prod.alphabravo.io/ghost-base/kafka-exporter:<tag>
          args:
            - --kafka.server=kafka:9092
          ports:
          - containerPort: 9308
            name: metrics
      imagePullSecrets:
        - name: <your-registry-secret>
---
apiVersion: v1
kind: Service
metadata:
  name: kafka-exporter
  namespace: default
spec:
  ports:
    - port: 9308
      targetPort: 9308
  selector:
    app: kafka-exporter
EOF

Apply the manifests:

$ kubectl apply -n default -f kafka.yaml
$ kubectl apply -n default -f kafka-exporter.yaml

Verify the deployment:

$ kubectl get pods -n default
NAME                              READY   STATUS    RESTARTS   AGE
kafka-6959756cc4-bbkp9            1/1     Running   0          38s
kafka-exporter-6d4576bc86-p7f8h   1/1     Running   0          7s

Access the metrics:

$ kubectl port-forward -n default deployment/kafka-exporter 9308:9308
$ curl http://localhost:9308/metrics | grep kafka_brokers
kafka_brokers 1

For examples of how to configure Kafka Exporter itself, see the Kafka Exporter documentation.

Non-hardened images vs Ghost hardened images

Key differences

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>

Or mount debugging tools with the image mount feature:

$ docker run --rm -it --pid container:my-container \
  --mount=type=image,source=registry.ghost-prod.alphabravo.io/ghost-base/busybox:<tag>,destination=/dbg,ro \
  registry.ghost-prod.alphabravo.io/ghost-base/kafka-exporter:<tag> /dbg/bin/sh

Image variants

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

The Kafka Exporter image provides only runtime 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

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 Kafka Exporter 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 kafka-exporter

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

Runtime requirements specific to FIPS:

• FIPS mode enforces stricter cryptographic standards
• Use FIPS variants when connecting to Kafka clusters 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.