Senior Site Reliability Engineer (SRE, Compute Node Team)

About Halcyon Labs: Halcyon Labs is leading a new era in cloud infrastructure for the global AI economy. We are building a full-stack AI cloud platform that supports developers and enterprises from data and model training through to production deployment, without the cost and complexity of building large in-house AI/ML infrastructure. Built by engineers, for engineers. From large-scale GPU orchestration to inference optimization, we own the hard problems across compute, storage, networking and applied AI. Listed on Nasdaq (NBIS) and headquartered in Amsterdam, we have a global footprint with R&D hubs across Europe, the UK, North America and Israel. Our team of 1,500+ includes hundreds of engineers with deep expertise across hardware, software and AI R&D. The Role We are looking for a Senior Site Reliability Engineer (SRE) to join the Compute Node team at Halcyon Labs AI Cloud. The Compute Node team is responsible for building and operating the cluster scheduler and node-level services that run and manage virtual machines across all cloud regions. This role focuses on Linux systems engineering, virtualization and operational reliability. You will work close to the operating system and hypervisor, shaping how reliability and observability are embedded into the Compute platform. Y our responsibilities will include: Ensure reliability, availability and performance of compute nodes running VMs Analyze and debug Linux systems across user space and kernel space, understanding capabilities, limitations and trade-offs at each layer Troubleshoot complex production issues involving CPU, memory, NUMA, cgroups and scheduling Work hands-on with virtualization and containerization, primarily using QEMU/KVM and Linux-native technologies Design and evolve observability as a core capability of the node layer: metrics, logs, traces, alerts, SLIs and SLOs Lead incident response, root-cause analysis, and postmortems, driving long-term reliability improvements Collaborate closely with platform, kernel/hypervisor, GPU and infrastructure teams to improve system design and operability We expect you to have: Strong Linux expertise: deep understanding of Linux user space and kernel space knowledge of kernel subsystems (scheduler, memory management, filesystems, cgroups, namespaces) clear understanding of system boundaries and constraints at different layers Virtualization experience: hands-on experience with QEMU/KVM understanding of VM lifecycle, performance characteristics and failure modes Containerization knowledge: practical experience with containers, namespaces and cgroups strong understanding of resource isolation and control Strong debugging skills: ability to reason about complex system failures structured, hypothesis-driven approach to incident analysis SRE mindset: clear understanding of the SRE role in system design and operations experience building and operating observability stacks, not just consuming them ability to turn system behavior into actionable reliability signals Nice to Have / Optional: Experience with Kubernetes internals or node-level components Hands-on experience with low-level Linux debugging tools (e.g. perf, eBPF, ftrace, strace, kernel crash dumps) Familiarity with large-scale compute or bare-metal platforms Contributions to open-source infrastructure or system software Experience debugging hardware and driver-level issues, including GPUs, NVLink, InfiniBand Benefits & Perks: Competitive compensation Career growth and learning opportunities Flexibility and ownership Collaborative and innovative culture Opportunity to work on impactful AI projects International environment and talented teams What's it like to work at Halcyon Labs: Fast moving - Bold thinking - Constant growth - Meaningful impact - Trust and real ownership - Opportunity to shape the future of AI Equal Opportunity Statement: Halcyon Labs is an equal opportunity employer. We are committed to fostering an inclusive and diverse workplace and to providing equal employment opportunities in all aspects of employment. We do not discriminate on the basis of race, color, religion, sex (including pregnancy), national origin, ancestry, age, disability, genetic information, marital status, veteran status, sexual orientation, gender identity or expression, or any other characteristic protected by applicable law. Applicants must be authorized to work in the country in which they apply and will be required to provide proof of employment eligibility as a condition of hire. If you need accommodations during the application process, please let us know.