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