Over ten months, Brad Cressey engineered core features and reliability improvements for Bottlerocket OS, focusing on the bottlerocket-core-kit and bottlerocket-kernel-kit repositories. He enhanced system security and performance by integrating SELinux policy hardening, zram-backed swap, and nftables support, while modernizing build systems for reproducibility and cross-architecture stability. Brad used C, Rust, and Shell scripting to implement kernel configuration changes, optimize memory management, and streamline package management. His work addressed supply-chain integrity with GPG verification, improved Kubernetes compatibility, and reduced technical debt through modularization and codebase cleanup, demonstrating depth in low-level systems programming and secure Linux platform development.
July 2025 monthly summary: Across bottlerocket-core-kit and bottlerocket-kernel-kit, delivered security hardening, memory management improvements, and kernel security enhancements. Key features delivered include: SELinux MCS restrictions on mounts to harden container isolation; zram-backed swap with a new subpackage and systemd service to improve memory management under low-memory conditions; added JSON support for nftables via libjansson to satisfy kube-proxy requirements and updated build configuration. In kernel-kit, enabled ZBoot support for aarch64 with Secure Boot, default zram compression set to LZ4 to align with 6.12, and enabled Landlock LSM for 6.1 and 6.12 to improve mandatory access control. Major bugs fixed: none reported in this period; focus on delivering these features with careful integration testing. Overall impact and accomplishments: strengthens container isolation, improves memory resilience, and enhances platform security and Kubernetes readiness across architectures. Technologies/skills demonstrated: SELinux MCS, zram, systemd packaging, libjansson integration, JSON support in nftables, ZBoot, kernel configuration for Secure Boot, cross-arch builds, and Landlock LSM.
July 2025 monthly summary: Across bottlerocket-core-kit and bottlerocket-kernel-kit, delivered security hardening, memory management improvements, and kernel security enhancements. Key features delivered include: SELinux MCS restrictions on mounts to harden container isolation; zram-backed swap with a new subpackage and systemd service to improve memory management under low-memory conditions; added JSON support for nftables via libjansson to satisfy kube-proxy requirements and updated build configuration. In kernel-kit, enabled ZBoot support for aarch64 with Secure Boot, default zram compression set to LZ4 to align with 6.12, and enabled Landlock LSM for 6.1 and 6.12 to improve mandatory access control. Major bugs fixed: none reported in this period; focus on delivering these features with careful integration testing. Overall impact and accomplishments: strengthens container isolation, improves memory resilience, and enhances platform security and Kubernetes readiness across architectures. Technologies/skills demonstrated: SELinux MCS, zram, systemd packaging, libjansson integration, JSON support in nftables, ZBoot, kernel configuration for Secure Boot, cross-arch builds, and Landlock LSM.
June 2025 monthly summary for bottlerocket-core-kit: Delivered three major features/enhancements across memory management, networking tooling, and security policy. This work produced tangible performance, security, and operational benefits for Kubernetes workloads on Bottlerocket clusters.
June 2025 monthly summary for bottlerocket-core-kit: Delivered three major features/enhancements across memory management, networking tooling, and security policy. This work produced tangible performance, security, and operational benefits for Kubernetes workloads on Bottlerocket clusters.
May 2025 monthly work summary focusing on key accomplishments across bottlerocket-core-kit and bottlerocket-kernel-kit. Notable themes include build stability, security hardening, system orchestration, packaging modularization, and kernel packaging improvements. These efforts reduce risk in releases, improve boot reliability, and streamline dependencies while delivering measurable business value.
May 2025 monthly work summary focusing on key accomplishments across bottlerocket-core-kit and bottlerocket-kernel-kit. Notable themes include build stability, security hardening, system orchestration, packaging modularization, and kernel packaging improvements. These efforts reduce risk in releases, improve boot reliability, and streamline dependencies while delivering measurable business value.
In April 2025, delivered reliability and performance improvements across Bottlerocket core and kernel kits, with a focus on stability, boot optimization, and developer usability. The work balanced bug fixes, feature enhancements, and packaging improvements that translate into tangible customer value and faster time-to-market for platform features.
In April 2025, delivered reliability and performance improvements across Bottlerocket core and kernel kits, with a focus on stability, boot optimization, and developer usability. The work balanced bug fixes, feature enhancements, and packaging improvements that translate into tangible customer value and faster time-to-market for platform features.
March 2025 monthly summary for Bottlerocket OS development focused on security, performance, and maintainability improvements across kernel-kit and core-kit, with packaging refinements enabling TPM tooling and AWS credential workflows. The work delivered strengthens boot integrity, container performance, and operational automation while reducing technical debt.
March 2025 monthly summary for Bottlerocket OS development focused on security, performance, and maintainability improvements across kernel-kit and core-kit, with packaging refinements enabling TPM tooling and AWS credential workflows. The work delivered strengthens boot integrity, container performance, and operational automation while reducing technical debt.
February 2025 monthly summary: Delivered cross-repo features and reliability improvements across Bottlerocket core-kit and kernel-kit, emphasizing performance, security, and compatibility to advance business value and operational efficiency. Key capabilities were introduced and backported with a strong traceable commit history, while build reliability and SDK compatibility were strengthened.
February 2025 monthly summary: Delivered cross-repo features and reliability improvements across Bottlerocket core-kit and kernel-kit, emphasizing performance, security, and compatibility to advance business value and operational efficiency. Key capabilities were introduced and backported with a strong traceable commit history, while build reliability and SDK compatibility were strengthened.
January 2025 — Bottlerocket Core Kit: Cross-Platform Libcap Build Flags Stabilization to improve build reliability across target architectures. Replaced %optflags with %__global_compiler_flags to avoid architecture-specific host flags, ensuring packaged artifacts are reliably built across target architectures. This change reduces environment-specific build failures and supports smoother multi-arch packaging and releases.
January 2025 — Bottlerocket Core Kit: Cross-Platform Libcap Build Flags Stabilization to improve build reliability across target architectures. Replaced %optflags with %__global_compiler_flags to avoid architecture-specific host flags, ensuring packaged artifacts are reliably built across target architectures. This change reduces environment-specific build failures and supports smoother multi-arch packaging and releases.
December 2024 Monthly Summary (bottlerocket-os projects) Key focus: reinforce supply-chain integrity, stabilize the build system, and modernize core libraries across core-kit and kernel-kit to improve security, reproducibility, and maintainability. Overview of work: - Core-kit (bottlerocket-core-kit): Implemented global GPG verification for downloaded sources across core packages, added signature files and verification steps to ensure authenticity and integrity of build artifacts. Updated core libraries and metadata to the latest stable versions to improve security and compatibility. This included updates to liburcu, libncurses, iproute, libelf, libnl, strace, libnl, and related components, and backfilled release URLs for build references. - Kernel-kit (bottlerocket-kernel-kit): Expanded GPG verification to packages including grub, kernel variants (5.10, 5.15, 6.1), libkcapi, linux-firmware, microcode, and shim; introduced and distributed GPG public keys and updated build specs to enforce signature checks. Key achievements (top 5): - Global GPG verification implemented across core-kit sources, significantly strengthening supply-chain authenticity checks (commits across multiple packages: 3b016a134a6aa1f55dc58f08ed829fbf80e0a98f; ed8d8627276278bdfe89701f8dbb17667ba619d9; 288893534692cdf42be66729fb49c58e9c27d9d5; 3135c5e1de373d2b956f1e0149806ea4d15181c8; 3806fedfba50393a9b5c50b8354329b2ee41e2de; d545156d925b6a7ae767d3bcb2dec0adffe40be7; 4f1557b85fe34f0962c2c43a16e9318c83f1f315; d9af14378049bcb229a1ae45df023a3496aba73a; c243d3ad646e2974ad7b3fa0fd86c63fc28a6d2d). - Kernel-kit extended GPG verification across critical packages, reinforcing integrity of grub, kernel builds, and firmware-related components (commit: 442c456d920b30caf9b9d827b09ca8bdd09516b2). - Core-library modernization: updated libglib to 2.83.0, libtirpc to 1.3.6, chrony to 4.6.1, and ensured release-URL backfill for reproducible builds. - Build-system hardening: alignment of source references and metadata to latest stable versions improves security posture and compatibility. - Reproducibility and auditability improvements: signature checks, GPG keys distribution, and build metadata hygiene streamline audits and compliance. Business impact: - Strengthened security and trust in delivered artifacts, reducing risk of supply-chain compromises. - Improved stability and compatibility for downstream deployments through up-to-date libraries and verified builds. - Enhanced reproducibility and auditability of releases, accelerating compliance and incident response. Technologies and skills demonstrated: - GPG-based code and package signing, public-key distribution, and verification in build pipelines. - Build-system maintenance: library version management, metadata hygiene, and release URL backfilling. - Cross-repo collaboration between core-kit and kernel-kit to extend security guarantees across the product.
December 2024 Monthly Summary (bottlerocket-os projects) Key focus: reinforce supply-chain integrity, stabilize the build system, and modernize core libraries across core-kit and kernel-kit to improve security, reproducibility, and maintainability. Overview of work: - Core-kit (bottlerocket-core-kit): Implemented global GPG verification for downloaded sources across core packages, added signature files and verification steps to ensure authenticity and integrity of build artifacts. Updated core libraries and metadata to the latest stable versions to improve security and compatibility. This included updates to liburcu, libncurses, iproute, libelf, libnl, strace, libnl, and related components, and backfilled release URLs for build references. - Kernel-kit (bottlerocket-kernel-kit): Expanded GPG verification to packages including grub, kernel variants (5.10, 5.15, 6.1), libkcapi, linux-firmware, microcode, and shim; introduced and distributed GPG public keys and updated build specs to enforce signature checks. Key achievements (top 5): - Global GPG verification implemented across core-kit sources, significantly strengthening supply-chain authenticity checks (commits across multiple packages: 3b016a134a6aa1f55dc58f08ed829fbf80e0a98f; ed8d8627276278bdfe89701f8dbb17667ba619d9; 288893534692cdf42be66729fb49c58e9c27d9d5; 3135c5e1de373d2b956f1e0149806ea4d15181c8; 3806fedfba50393a9b5c50b8354329b2ee41e2de; d545156d925b6a7ae767d3bcb2dec0adffe40be7; 4f1557b85fe34f0962c2c43a16e9318c83f1f315; d9af14378049bcb229a1ae45df023a3496aba73a; c243d3ad646e2974ad7b3fa0fd86c63fc28a6d2d). - Kernel-kit extended GPG verification across critical packages, reinforcing integrity of grub, kernel builds, and firmware-related components (commit: 442c456d920b30caf9b9d827b09ca8bdd09516b2). - Core-library modernization: updated libglib to 2.83.0, libtirpc to 1.3.6, chrony to 4.6.1, and ensured release-URL backfill for reproducible builds. - Build-system hardening: alignment of source references and metadata to latest stable versions improves security posture and compatibility. - Reproducibility and auditability improvements: signature checks, GPG keys distribution, and build metadata hygiene streamline audits and compliance. Business impact: - Strengthened security and trust in delivered artifacts, reducing risk of supply-chain compromises. - Improved stability and compatibility for downstream deployments through up-to-date libraries and verified builds. - Enhanced reproducibility and auditability of releases, accelerating compliance and incident response. Technologies and skills demonstrated: - GPG-based code and package signing, public-key distribution, and verification in build pipelines. - Build-system maintenance: library version management, metadata hygiene, and release URL backfilling. - Cross-repo collaboration between core-kit and kernel-kit to extend security guarantees across the product.
2024-11 Monthly Summary: Focused on strengthening boot observability, NVMe tooling, and packaging stability across Bottlerocket core components and kernel integration. Delivered observable business value through improved boot-time diagnostics, richer NVMe metrics for storage workloads, and more robust, maintainable build pipelines. Technical achievements include Boot Loader Interface (BLI) support for GRUB enabling systemd-analyze reporting of firmware/bootloader times, JSON-C integration for NVMe plugins, an EBS statistics reporting enhancement in nvme-cli, and stability-focused packaging and kernel build changes.
2024-11 Monthly Summary: Focused on strengthening boot observability, NVMe tooling, and packaging stability across Bottlerocket core components and kernel integration. Delivered observable business value through improved boot-time diagnostics, richer NVMe metrics for storage workloads, and more robust, maintainable build pipelines. Technical achievements include Boot Loader Interface (BLI) support for GRUB enabling systemd-analyze reporting of firmware/bootloader times, JSON-C integration for NVMe plugins, an EBS statistics reporting enhancement in nvme-cli, and stability-focused packaging and kernel build changes.
In October 2024, Bottlerocket Core Kit delivered security and dependency-management improvements that strengthen compliance, reproducibility, and maintainability. Key changes include aligning libkcapi packaging with FIPS 140-3 and Amazon Linux 2023 upstream, and simplifying workspace dependencies to reduce maintenance overhead. No major bug fixes were reported this month.
In October 2024, Bottlerocket Core Kit delivered security and dependency-management improvements that strengthen compliance, reproducibility, and maintainability. Key changes include aligning libkcapi packaging with FIPS 140-3 and Amazon Linux 2023 upstream, and simplifying workspace dependencies to reduce maintenance overhead. No major bug fixes were reported this month.
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