Upgrade to PRO for Only $50/Year—Limited-Time Offer! 🔥

Creating Secure Container Images with apko

Erika Heidi
September 29, 2022

Creating Secure Container Images with apko

This talk was presented at the Full Stack NL meetup group on September 29, 2022.

Erika Heidi

September 29, 2022
Tweet

More Decks by Erika Heidi

Other Decks in Technology

Transcript

  1. What to Expect from this Talk • What is apko

    ◦ Tool overview ◦ Why apk • Why Distroless • Case Study / Demo ◦ Migrating dynacover to a distroless apko image • Q&A
  2. What is apko • Declarative OCI image builder tool based

    on apk • Part of the building toolkit behind Wolfi / Chainguard Images • Images are defined in YAML files • Builds are fully reproducible • Automatically generates SBOMs for every image • Platform-agnostic builds via Docker + apko image
  3. Building the image with apko via Docker $ docker run

    --rm -v ${PWD}:/work cgr.dev/chainguard/apko build alpine-base.yaml alpine-base:test alpine-test.tar Testing the image with Docker $ docker load < alpine-test.tar $ docker run -it alpine-base:test
  4. Why apk • Introduced by Alpine, it uses a different

    methodology to handle package management • Package installation or removal is done as a side effect of modifying the system state • This creates the ideal conditions for reproducible and declarative pipelines
  5. Where do packages come from • For Alpine-based images, use

    Alpine apks found at pkgs.alpinelinux.org/packages • For Wolfi-based images, use Wolfi apks that are listed in the wolfi-os repository, hosted at packages.wolfi.dev/os • Don't mix! • You can also create your own apks with melange
  6. The distroless philosophy • Minimalist container images with only what's

    absolutely necessary to build or execute your application • Popular base images are full of software that only makes sense on bare-metal • No need for package managers or interactive shells on production images • Less dependencies = smaller attack surface, less CVEs
  7. Dynacover Overview • Dynamic header images for Twitter • PHP

    application built with Minicli • Main dependencies: PHP (cli), Curl and GD
  8. Dynacover Overview • GitHub Action that runs on schedule •

    Using an image based on the official php:7.4-cli ◦ Size: 589MB ◦ CVEs (Trivy): 331
  9. Migration step 1: collecting dependencies FROM php:7.4-cli ARG user=dynacover ARG

    uid=1000 RUN apt-get update && apt-get install -y git curl libonig-dev libxml2-dev libfreetype6-dev libjpeg62-turbo-dev libpng-dev zip unzip RUN apt-get clean && rm -rf /var/lib/apt/lists/* RUN docker-php-ext-configure gd --with-freetype --with-jpeg && \ docker-php-ext-install pdo_mysql mbstring exif pcntl bcmath gd COPY --from=composer:latest /usr/bin/composer /usr/bin/composer RUN useradd -G sudo,root -u $uid -d /home/$user $user RUN mkdir -p /home/$user/.composer && \ chown -R $user:$user /home/$user USER $user RUN mkdir -p /home/$user/dynacover COPY . /home/$user/dynacover/ WORKDIR /home/$user/dynacover RUN composer install • git • curl • zip • unzip • libonig-dev • libfreetype6-dev • libjpeg62-turbo-dev • libpng-dev • php-mbstring • php-exif • php-pcntl • php-bcmath • php-gd
  10. Migration step 3: creating the apko.yaml file contents: repositories: -

    https://dl-cdn.alpinelinux.org/alpine/edge/main - https://dl-cdn.alpinelinux.org/alpine/edge/community … … packages: - alpine-baselayout-data - ca-certificates-bundle - curl - git - zip - unzip - libxml2-dev - freetype - freetype-dev - libjpeg-turbo - libjpeg-turbo-dev - libpng - php81 - php81-gd - php81-curl - php81-mbstring - php81-phar - php81-openssl - php81-pcntl
  11. Migration step 3: creating the apko.yaml file entrypoint: command: /usr/bin/php81

    environment: PATH: /usr/sbin:/sbin:/usr/bin:/bin … … accounts: groups: - groupname: minicli gid: 65532 users: - username: minicli uid: 65532 run-as: root - php81-pcntl
  12. Migration step 4: building/pushing the image $ docker run --rm

    -v ${PWD}:/work cgr.dev/chainguard/apko build apko.yaml \ erikaheidi/minicli:php81 minicli-php81.tar $ docker load < minicli-php81.tar $ docker push erikaheidi/minicli:php81
  13. Migration step 5: updating GH Action Dockerfile FROM erikaheidi/minicli:php81 COPY

    --from=composer:latest /usr/bin/composer /usr/bin/composer RUN git clone -b 1.0.1 --depth 1 https://github.com/erikaheidi/dynacover.git && \ cd dynacover && \ composer install --no-progress --no-dev --prefer-dist ENTRYPOINT [ "php81", "/dynacover/dynacover" ] CMD ["cover", "update"]
  14. Dynacover base image: before / after • Based on php:7.4-cli

    • Base image total size: 589MB • Total CVEs: 331 • Distroless based on Alpine • Base image total size: 48MB • Total CVEs: 0
  15. Resources to Learn More • minicli:php81 on GitHub • Getting

    Started with apko tutorial on Chainguard Academy • apko on GitHub • Troubleshooting apko builds • Chainguard Images documentation • Wolfi documentation