cd/docs/operator-manual/custom_tools.md

Custom Tooling

Hanzo CD bundles preferred versions of its supported templating tools (helm, kustomize, ks, jsonnet) as part of its container images. Sometimes, it may be desired to use a specific version of a tool other than what Hanzo CD bundles. Some reasons to do this might be:

• To upgrade/downgrade to a specific version of a tool due to bugs or bug fixes.
• To install additional dependencies to be used by kustomize's configmap/secret generators. (e.g. curl, vault, gpg, AWS CLI)
• To install a config management plugin.

As the Hanzo CD repo-server is the single service responsible for generating Kubernetes manifests, it can be customized to use alternative toolchain required by your environment.

Adding Tools Via Volume Mounts

The first technique is to use an init container and a volumeMount to copy a different version of a tool into the repo-server container. In the following example, an init container is overwriting the helm binary with a different version than what is bundled in Hanzo CD:

    spec:
      # 1. Define an emptyDir volume which will hold the custom binaries
      volumes:
      - name: custom-tools
        emptyDir: {}
      # 2. Use an init container to download/copy custom binaries into the emptyDir
      initContainers:
      - name: download-tools
        image: alpine:3.8
        command: [sh, -c]
        args:
        - wget -qO- https://get.helm.sh/helm-v2.12.3-linux-amd64.tar.gz | tar -xvzf - &&
          mv linux-amd64/helm /custom-tools/
        volumeMounts:
        - mountPath: /custom-tools
          name: custom-tools
      # 3. Volume mount the custom binary to the bin directory (overriding the existing version)
      containers:
      - name: cd-repo-server
        volumeMounts:
        - mountPath: /usr/local/bin/helm
          name: custom-tools
          subPath: helm

BYOI (Build Your Own Image)

Sometimes replacing a binary isn't sufficient, and you need to install other dependencies. The following example builds an entirely customized repo-server from a Dockerfile, installing extra dependencies that may be needed for generating manifests.

FROM ghcr.io/hanzoai/cd:v2.5.4 # Replace tag with the appropriate cd version

# Switch to root for the ability to perform install
USER root

# Install tools needed for your repo-server to retrieve & decrypt secrets, render manifests 
# (e.g. curl, awscli, gpg, sops)
RUN apt-get update && \
    apt-get install -y \
        curl \
        awscli \
        gpg && \
    apt-get clean && \
    rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/* && \
    curl -o /usr/local/bin/sops -L https://github.com/mozilla/sops/releases/download/3.2.0/sops-3.2.0.linux && \
    chmod +x /usr/local/bin/sops

# Switch back to non-root user
USER $CD_USER_ID