How to use this image

All examples in this guide use the public image. If you’ve mirrored the repository for your own use (for example, to your Docker Hub namespace), update your commands to reference the mirrored image instead of the public one.

For example:

• Public image: dhi.io/<repository>:<tag>
• Mirrored image: <your-namespace>/dhi-<repository>:<tag>

For the examples, you must first use docker login dhi.io to authenticate to the registry to pull the images.

What's included in this Hyperledger Fabric Tools Hardened image

Hyperledger Fabric Tools is a collection of command-line utilities for managing and configuring Hyperledger Fabric blockchain networks. This hardened image includes six essential tools: configtxgen for generating channel configuration artifacts, configtxlator for translating configuration between binary and JSON formats, cryptogen for generating cryptographic key material, discover for service discovery, ledgerutil for ledger maintenance operations, and osnadmin for managing orderer channels. The hardened image provides the same functionality as upstream Hyperledger Fabric but runs with Docker Hardened Image security guarantees.

These tools are primarily used during network setup, configuration updates, and maintenance operations. They enable administrators to create genesis blocks, generate channel transaction configurations, manage cryptographic identities, inspect and modify channel configurations, and perform administrative tasks on orderer nodes.

Using Hyperledger Fabric Tools

Run commands using docker run with Hyperledger Fabric Tools. Replace <tag> with the desired version.

docker run --rm dhi.io/hyperledger-fabric-tools:<tag> configtxgen -version

Generate a sample cryptogen configuration template and save it to a file:

docker run --rm dhi.io/hyperledger-fabric-tools:<tag> cryptogen showtemplate > crypto-config.yaml

To use tools with configuration files, mount directories and use volume mounts. For example, generate cryptographic material with cryptogen:

# Generate crypto material using the template
docker run --rm \
  -v $(pwd):/work \
  dhi.io/hyperledger-fabric-tools:<tag> \
  cryptogen generate --config=/work/crypto-config.yaml --output=/work/crypto-config

This command generates X.509 certificates and keys for orderers and peers based on the crypto-config.yaml specification. The output is written to the crypto-config directory on your host. For tools like configtxgen that use FABRIC_CFG_PATH, mount your config directory with -v and set the environment variable with -e FABRIC_CFG_PATH=/config.

Common Hyperledger Fabric Tools use cases

Non-hardened images vs Docker Hardened Images

Key differences

Hardened image debugging

Docker Hardened Images for Hyperledger Fabric Tools do not include a shell or package manager to minimize the attack surface and reduce image size. This means you cannot use docker exec to access a shell inside a running container. However, Docker provides alternative debugging methods that work seamlessly with hardened images.

The recommended approach is to use Docker Debug⁠, which attaches an ephemeral debug container with a shell and common debugging tools to your running container. This allows you to inspect the container's filesystem, processes, and network configuration without modifying the production image.

For Hyperledger Fabric Tools specifically, you can also debug by examining the output artifacts (genesis blocks, configuration files, certificates) generated by the tools. Mount volumes to persist these outputs and inspect them on your host system. Additionally, enable verbose logging by checking tool-specific flags (many tools support -v or --verbose flags).

Using Docker Debug

Attach a debug shell to a running Hyperledger Fabric Tools container:

docker debug <container-name>

This opens a shell in the debug container where you can inspect the filesystem, check running processes with ps, or examine network connections with netstat.

Using Docker Image Mount

Mount the container's filesystem to your host for inspection:

docker image mount dhi.io/hyperledger-fabric-tools:<tag> /mnt/inspect
ls -la /mnt/inspect/usr/local/bin/

Examining generated artifacts

Since the tools generate configuration files and cryptographic material, debug by inspecting outputs:

# Generate crypto material
docker run --rm -v $(pwd):/work \
  dhi.io/hyperledger-fabric-tools:<tag> \
  cryptogen generate --config=/work/crypto-config.yaml --output=/work/crypto-config

# Inspect the generated certificates on your host
ls -la crypto-config/peerOrganizations/
openssl x509 -in crypto-config/peerOrganizations/org1.example.com/ca/ca.org1.example.com-cert.pem -text -noout | head -20

Image variants

Docker Hardened Images come in different variants depending on their intended use.

• 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

• Build-time variants typically include dev in the variant name and are intended for use in the first stage of a multi-stage Dockerfile. These images typically:

  • Run as the root user
  • Include a shell and package manager
  • Are used to build or compile applications

Migrate to a Docker Hardened Image

To migrate your application to a Docker Hardened Image, you must update your Dockerfile. At minimum, you must update the base image in your existing Dockerfile to a Docker 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

   Docker 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.

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 Docker 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

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

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