SoftCloud Node Linux

Welcome to SoftCloud Node Linux, a dedicated, reproducible Linux distribution engineered specifically for Kubernetes nodes executed as FreeBSD bhyve virtual machines, published at linux.softcloud.dev.

SoftCloud Node Linux is neither a customized Ubuntu installation nor a generic Debian server image. It is a purpose-built, deterministic operating system artifact produced by soft-cloud-dev/os-linux and consumed directly by soft-cloud-dev/freebsd-laboratory.

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Architectural Principles & Organizational Pillars

In alignment with the core engineering standards of the Software Cloud organization, SoftCloud Node Linux is governed by four primary pillars:

1. Cryptographic Reproducibility: All dependencies and build inputs resolve to immutable, cryptographic SHA-256 digests (--require-hashes, --only-binary=:all:). The release pipeline targets level R4 reproducibility, requiring two independent clean builds to yield bit-identical raw disk images (softcloud-node-amd64.raw).

2. Hermetic & Isolated Execution: Build processes strictly isolate the network fetch-and-verify phase from the canonical builder. Canonical kernel, userspace (mmdebstrap), and UKI compilation execute with external network access completely disabled (BUILD-01 through BUILD-05).

3. Strict Profile Conformance: Every release artifact and build pipeline adheres to formal JSON schemas (softcloud.os/v1, softcloud.node/v1, and softcloud.artifact/v1). Standalone preflight validators enforce structural integrity, kernelspec compliance, and schema validity before artifact promotion.

4. Continuous Delivery & Formal Provenance: Every commit and release is built, validated, and signed through automated CI/CD. Releases generate comprehensive software supply chain artifacts, including SPDX SBOMs, SLSA-grade provenance manifests, and cryptographic checksum manifests (SHA256SUMS).

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Core System Architecture

                     +-----------------------------------+
                     |      soft-cloud-dev/os-linux      |
                     +-----------------------------------+
                                       |
                       (Hermetic Build & Verification)
                                       v
                          softcloud-node-amd64.raw
                                       |
                   +-------------------+-------------------+
                   |                   |                   |
                   v                   v                   v
              k8s-cp1 (bhyve)     k8s-w1 (bhyve)      k8s-w2 (bhyve)
                   |                   |                   |
              CIDATA Seed A       CIDATA Seed B       CIDATA Seed C
                   |                   |                   |
                   +-------------------+-------------------+
                                       |
                     +-----------------------------------+
                     |    freebsd-laboratory Cluster     |
                     |         Kubernetes + Cilium       |
                     +-----------------------------------+

• Boot Pipeline: Direct UEFI boot via EDK2 loading a self-contained Unified Kernel Image (UKI) at /EFI/BOOT/BOOTX64.EFI. Does not depend on persistent NVRAM variables.
• Kernel Configuration: Tailored Linux 6.18 LTS profile (kernel/config/linux-kubernetes-bhyve.config) featuring built-in VirtIO block/PCI/net drivers, ext4 root, cgroup v2, and verified eBPF BTF (CONFIG_DEBUG_INFO_BTF=y).
• Disk Layout & State Separation: Three-partition GPT containing:
  • p1 (ESP, FAT32): Self-contained UKI.
  • p2 (OS root, ext4): Deterministic release filesystem.
  • p3 (node-state, dynamic ext4): Provisioned and auto-expanded via systemd-repart, projecting state into /var/lib/containerd, /var/lib/kubelet, /var/lib/etcd, and /var/log using systemd bind mounts.
• Machine Bootstrap (softcloud.node/v1): Clean cloud-init replacement utilizing systemd device activation (dev-disk-by\x2dlabel-CIDATA.device) and a persistent one-shot initialization marker preventing accidental reconfiguration.
• Runtime Stack: Native containerd and kubelet under the systemd cgroup driver, with early shared /sys/fs/bpf mount propagation (rshared) satisfying Cilium CNI prerequisites before container daemon activation.

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Documentation Roadmap

• Introduction: Background, operational scope, and the system boundary dividing artifact producer (os-linux) and consumer (freebsd-laboratory).
• SoftCloud Node Linux Memorandum: The normative specification baseline (SOFTCLOUD-NODE-LINUX-1.0) establishing all 32 architectural sections and 35 acceptance criteria (SN-01 through SN-35).
• Adoption Plan: Comprehensive, phased operational adoption roadmap based on organizational rules, covering implementation milestones, verification gates, supply chain conformance, and rollout runbooks.
• Computational Verification: Executable runtime validation notebook executed during the build pipeline under the canonical jb2-python kernel.