Principal Systems Software Engineer

Crusoe is on a mission to accelerate the abundance of energy and intelligence. As the only vertically integrated AI infrastructure company built from the ground up, we own and operate each layer of the stack — from electrons to tokens — to power the world's most ambitious AI workloads. When you join Crusoe, you join a team that is building the future, faster.We're in the midst of the greatest industrial revolution of our time. The demand for AI compute is boundless, and power is a bottleneck. We're solving that — with an energy-first approach that makes AI infrastructure better for the world and faster for the people innovating with AI.We're looking for problem-solving, opportunity-finding teammates with a sense of urgency, who believe in the scale of our ambition and thrive on a path not fully paved — people who want to grow their careers alongside a team of experts across energy, manufacturing, data center construction, and cloud services.If you want to do the most meaningful work of your career, help our customers and partners advance their AI strategies, and be part of a high-performing team that believes in each other, come build with us at Crusoe.About This Role:As the Principal Systems Software Engineer, you will serve as the visionary lead for Crusoe’s next-generation AI infrastructure. This is a role for an industry-recognized expert who has already "seen the movie" at hyperscale and is ready to redefine the I/O path for the age of generative AI. You aren't just building a cloud; you are designing the fluid fabric that unifies Bare-Metal-as-a-Service (BMaaS), Intelligent IaaS, and Elastic CaaS into a single, high-performance pool of intelligence.In this position, you will bridge the gap between silicon and software, advising executive leadership on critical hardware/software co-design pivots while remaining hands-on enough to lead elite R&D teams in shipping production-grade kernel and orchestration code. We are looking for a master of the I/O path who can push massive-scale training workloads to the theoretical limits of hardware. This is a full-time position.What You’ll Be Working On:Unifying Infrastructure Pillars:Bare-Metal-as-a-Service (BMaaS): Architect systems that deliver raw GPU throughput via zero-latency InfiniBand/RDMA fabrics for massive-scale training.Intelligent IaaS: Design highly optimized, thin virtualization layers using KVM or custom micro-VMs to provide enterprise-grade isolation without the "virtualization tax."Elastic CaaS: Build a high-performance container substrate (utilizing Kubernetes or Slurm) that allows AI workloads to burst and scale across heterogeneous GPU nodes.Mastering the I/O Path: Lead the architectural design of our internal cloud fabric, drawing on experience from top-tier hyperscalers to drive the technical roadmap for SR-IOV, RDMA, and virtualized GPU scheduling.Advanced R&D Leadership: Lead elite workstreams to prototype and productionize novel methods for managing memory, networking, and compute that don't yet exist in standard cloud distributions.Technical Strategy & Documentation: Draft white papers and RFCs that define the next two years of Crusoe’s compute and networking stack.High-Level Debugging: Work alongside Staff and Senior engineers to resolve complex race conditions in the I/O path and optimize kernel-level memory pinning for GPU clusters.Industry Influence: Represent Crusoe in open-source communities and industry forums to influence the global direction of cloud-native AI infrastructure.What You’ll Bring to the Team:Hyperscale Provenance: 12+ years of experience designing and shipping core infrastructure at a major hyperscaler (e.g., OCI, AWS, Azure, GCP) or a specialized HPC cloud.Deep Systems Authority: Authoritative knowledge of the Linux kernel, virtualization internals (KVM, QEMU, Firecracker), and high-performance networking (RoCE v2, InfiniBand).Hardware-Software Co-Design: Proven ability to design software that maximizes the performance of NVIDIA/AMD GPUs and high-speed NICs.R&D Leadership: Experience leading cross-functional teams through high-ambiguity projects and delivering production-ready, mission-critical systems.Industry Contributions: A portfolio of significant contributions to the field, which may include patents, major open-source contributions, or published research in distributed systems.Communication Mastery: The rare ability to explain the nuances of memory-mapped I/O to an engineer and the business value of a new fabric architecture to the Board.Mandatory Education: A Bachelor’s or Master’s degree in Computer Science, Computer Engineering, or a related analytical field (or equivalent professional experience).Bonus Points:Patent Holder: Possession of patents related to network virtualization, GPU scheduling, or distributed file systems.Open Source Leadership: Maintainer status or significant contributions to the Linux Kernel, Kubernetes, or specialized HPC projects.AI/ML Workload Expertise: Direct experience optimizing infrastructure for Large Language Model (LLM) training and inference at scale.Peer-reviewed publications at top systems venues (OSDI, SOSP, NSDI, SC), patents, IETF RFCsSignificant open-source contributions, or industry white papers on distributed systems, high-performance networking, or AI infrastructureBenefitsCompetitive compensationRestricted Stock UnitsPaid time off & paid holidaysComprehensive health, dental & vision insuranceEmployer contributions to HSA accountPaid parental leavePaid life insurance, short-term and long-term disabilityProfessional development & tuition reimbursementMental health & wellness supportCommuter benefits (parking & transit)Cell phone stipend401(k) Retirement plan with company match up to 4% of salaryVolunteer time offCompensation Range$260,000 - $340,000 + Significant Equity & Bonus. Compensation is determined by the applicant's depth of expertise, previous impact at scale, and alignment with our architectural goals.Crusoe is an Equal Opportunity Employer. Employment decisions are made without regard to race, color, religion, disability, genetic information, pregnancy, citizenship, marital status, sex/gender, sexual preference/ orientation, gender identity, age, veteran status, national origin, or any other status protected by law or regulation.LocationSan Francisco, CA - USEmployment TypeFull timeLocation TypeOn-siteDepartmentCloud Engineering