filebeat

Run Filebeat with Compose and a custom configuration

This example shows Filebeat shipping logs to Elasticsearch with Kibana for visualization. It uses a custom filebeat.yml configuration file and mounts a local logs directory into the container to read log files.

First, create a compose.yaml file:

services:
  elasticsearch:
    image: registry.ghost-prod.alphabravo.io/ghost-base/elasticsearch:<tag>
    environment:
      - discovery.type=single-node
      - xpack.security.enabled=false
    ports:
      - "9200:9200"

  kibana:
    image: registry.ghost-prod.alphabravo.io/ghost-base/kibana:<tag>
    environment:
      - ELASTICSEARCH_HOSTS=http://elasticsearch:9200
    ports:
      - "5601:5601"
    depends_on:
      - elasticsearch
    volumes:
      - kibana_conf:/opt/kibana/kibana-<tag>/config

  filebeat:
    image: registry.ghost-prod.alphabravo.io/ghost-base/filebeat:<tag>
    volumes:
      - ./filebeat.yml:/usr/share/filebeat/filebeat.yml:ro
      - ./logs:/var/log:ro
    depends_on:
      - elasticsearch

volumes:
  kibana_conf:

Then, create a filebeat.yml configuration file:

filebeat.inputs:
- type: filestream
  enabled: true
  paths:
    - /var/log/*.log

output.elasticsearch:
  hosts: ["elasticsearch:9200"]

processors:
- add_host_metadata:
    when.not.contains.tags: forwarded

Run the Compose stack:

docker compose up -d

View logs in Kibana at http://localhost:5601

For more configuration options see the official Filebeat documentation.

Use Filebeat in Kubernetes

To use the Filebeat hardened image in Kubernetes, set up authentication and update your Kubernetes deployment. For example, in your filebeat.yaml file, replace the image reference in the container spec. In the following example, replace <tag> with the desired tag.

apiVersion: apps/v1
kind: Deployment
metadata:
  name: filebeat
  namespace: <kubernetes-namespace>
spec:
  template:
    spec:
      containers:
        - name: filebeat
          image: registry.ghost-prod.alphabravo.io/ghost-base/filebeat:<tag>
      imagePullSecrets:
        - name: <your-registry-secret>

Then apply the manifest to your Kubernetes cluster.

$ kubectl apply -n <kubernetes-namespace> -f filebeat.yaml

Image variants

Ghost hardened images come in different variants depending on their intended use. The Filebeat image comes in both runtime and build-time 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 the nonroot user

• Do not include a shell or a package manager

• Contain only the minimal set of libraries needed to run the app

• FIPS variants include fips in the variant name and tag. They come in both runtime and build-time variants. These variants use cryptographic modules that have been validated under FIPS 140, a U.S. government standard for secure cryptographic operations. For example, usage of MD5 fails in FIPS variants.

Non-hardened image vs. Ghost hardened image

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 <image-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,destination=/dbg,ro \
  registry.ghost-prod.alphabravo.io/ghost-base/<image-name>:<tag> /dbg/bin/sh

Migrate to a Ghost hardened image

Migrating to the hardened Filebeat image requires some adjustments due to differences in entrypoint and default behavior. While most configuration remains compatible, you'll need to account for the streamlined approach of the hardened image.

Migration steps

1. Update your image reference.

   Replace the image reference in your Docker run command or Compose file:

   • From: docker.elastic.co/beats/filebeat:<tag>
   • To: registry.ghost-prod.alphabravo.io/ghost-base/filebeat:<tag>

2. Adjust command arguments if needed.

   The hardened image uses a direct filebeat entrypoint instead of the tini wrapper.

   If you override the default command, ensure your arguments are compatible with the filebeat binary directly.

3. Verify configuration compatibility.

   Your existing environment variables, volume mounts, and network settings should remain the same, but test thoroughly as the hardened image may behave differently in edge cases.

General migration considerations

While the specific configuration requires no changes, be aware of these general differences in Ghost hardened images:

Troubleshooting migration

The following are common issues that you may encounter during 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. To avoid issues, configure your application to listen on port 1025 or higher inside the container, even if you map it to a lower port on the host.

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.