Principal Infrastructure Engineer

ABOUT THE ROLE Location: UK (occasional office travel) | Employment Type: Full-time, Permanent | Reports to: Engineering Manager We’re looking for a Principal Infrastructure Engineer in our Platform team to drive the architecture, design, and implementation of our next-generation AI-native cloud platform. You will analyse cutting-edge technologies, design scalable and resilient infrastructure solutions, and lead their implementation across a globally distributed environment. You’ll combine deep technical expertise with solution-focused leadership, you will enable our infrastructure to power HPC and AI/ML workloads, delivering value through innovation and collaboration. WHAT YOU'LL DO INFRASTRUCTURE DESIGN & VIRTUALISATION: • Architect, design and implement virtualisation solutions optimised for AI-native workloads, focusing on HPC environments and hypervisor tuning. • Design infrastructure that dynamically adjusts to meet customer demands for storage and networking resources, ensuring resilience and scalability. BARE-METAL AND OPERATING SYSTEM MANAGEMENT: • Lead the lifecycle management of bare-metal hardware, ensuring efficient provisioning, orchestration, and optimisation. • Maintain deep expertise in Unix/Linux systems, delivering secure, performant configurations at scale. NETWORKING AND HIGH-PERFORMANCE STORAGE: • Design and implement high-performance, cloud-native storage and networking solutions for demanding workloads. • Apply advanced knowledge of networking protocols (TCP, UDP, DNS, encryption) and software-defined networking (SDN) technologies. KUBERNETES AND CLOUD-NATIVE PLATFORMS: • Deploy and manage Kubernetes clusters across hybrid and multi-cloud environments, leveraging CNIs and service meshes. • Architect scalable CI/CD pipelines to automate infrastructure delivery and ensure reliable global operations. SECURITY AND AUDIT: • Kubernetes security hardening (RBAC, PSA/PSP successors, network policies, admission controllers - OPA/Gatekeeper, Kyverino) • Secrets management and rotation across clusters (Vault/OpenBao, sealed-secrets, external-secrets patterns) • Supply chain security — image scanning, signed artifacts (cosign/sigstore), provenance attestation • IAM and least-privilege design across bare-metal, cluster, and cloud control planes OBSERVABILITY AND AUTOMATION: • Build observability pipelines to monitor and troubleshoot global systems, integrating tools for logs,metrics, and tracing. • Create automation frameworks to reduce operational toil, streamline deployments, and enhance scalability using tools like Terraform, Ansible, Go, and Python. ARCHITECTURE & SOLUTION DESIGN: • Analyse emerging technologies and assess their potential fit within our platform, considering scalability, security, and performance. • Develop high- and low-level architectural proposals, balancing technical and business requirements. • Collaborate with cross-functional teams to ensure successful implementation of infrastructure solutions. • Provide thought leadership on architecture best practices, driving alignment across engineering and product teams. COLLABORATION AND LEADERSHIP: • Foster a 'how do we achieve this?' mindset, championing a positive, solution-oriented approach to challenges. • Mentor and guide team members in architectural principles, emerging technologies, and best practices. • Partner with engineering leaders and stakeholders to align infrastructure projects with broader organisational goals. WHAT YOU'LL BRING • Proven experience in infrastructure architecture and solution design, including the ability to produce detailed technical proposals. • Demonstrated success in evaluating and adopting new toolsets and technologies. • Extensive expertise in large-scale global infrastructure deployments, particularly in AI-native, HPC, and cloud-native environments. • Advanced knowledge of Kubernetes fundamentals, container networking (CNI), and service mesh technologies. • Deep understanding of virtualisation and hypervisor technologies for high-performance workloads. • Strong proficiency in networking protocols (TCP, UDP, DNS, BGP) and SDN solutions. • Skilled in Infrastructure-as-Code (IaC) tools like Terraform, Ansible, and cloud orchestration frameworks. • Hands-on coding experience in Go, Python, or similar languages for automation. • Solid grasp of observability tools (Prometheus, Grafana) and distributed tracing systems. • Strong communication and collaboration skills, with the ability to convey complex technical concepts to cross-functional teams. • Demonstrate ability to create clear and concise documentation for infrastructure designs, processes and systems. NICE TO HAVE • Expertise in AI/ML workloads, GPU-accelerated systems, or HPC infrastructures, including GPU partitioning with MIG and the NVIDIA GPU Operator. • Experience with RDMA fabrics such as InfiniBand or RoCEv2, and GPUDirect data paths. • High-throughput distributed storage at scale, such as Ceph or a parallel filesystem. • Familiarity with hybrid cloud and edge computing principles. • Experience leading architecture initiatives in agile environments, working iteratively to deliver high-quality results. WHY JOIN RADIANT • Work on a rapidly scaling AI infrastructure business at the forefront of the industry • Get broad exposure to a cutting-edge physical & software infrastructure stack • Be part of a team where you're genuinely valued and your work directly enables business decisions • Develop your career in a Brookfield-backed company with resources, mentorship, and genuine growth opportunities