Infrastructure Site Reliability Engineer

ABOUT RADIANT Radiant is redefining how AI infrastructure is built. We design and operate AI-native cloud platforms engineered for sovereignty, performance, and scale. Our infrastructure powers GPU-native workloads, multi-tenant control planes, and high-performance AI systems designed for the most demanding environments. We are not building a generic cloud. We are building purpose-built AI infrastructure - from powered land, to compute, to software . As we scale our platform and expand our engineering organisation, we are looking for leaders who can build strong teams, uphold high standards, and deliver reliably at pace. Job Summary: We’re looking for an experienced Infrastructure Site Reliability Engineer to run and evolve our infrastructure stack. You’ll contribute across bare-metal, virtualization, and orchestration layers, keeping things stable and secure 24/7 x 365 — all while mentoring teammates, improving process and automation as well as helping translate deep technical concepts for a wide range of collaborators and customers. What You’ll Do : - Deploy and operate resilient, scalable infrastructure supporting AI/HPC workloads - Optimize Linux system configuration, BIOS/firmware, kernel, and disk subsystem for performance - Configure, monitor and manage bare-metal infrastructure using IPMI, Redfish, etc - Build and maintain automation scripts and infrastructure as code to support platform lifecycle, as well as simplifying troubleshooting for Incident resolution and provision of tooling for our support organisation - Apply ITSM frameworks: Incident, Major Incident, Change Management, and service improvement. - Maintain and enhance ’s observability stack: Prometheus, Grafana, and custom monitoring integrations - Operate and support services in 24x7 production environments, including on-call rotation - Contribute to Incident postmortem analyses, root cause analysis, document learnings, and automate remediations - Mentor junior engineers and act as an Operational requirements consultant to other departments - Communicate technical decisions clearly to non-technical stakeholders and customers - Uphold a culture of: do, document, automate - Willingness to cross train with Platform Engineering/Platform SRE to fully support both our infrastructure and platform stacks. - Willingness to cross train with HPC Engineering, supported by NVIDIA to enhance our - HPC supportability offering What you bring: - 5+ Years Proven experience in globally scaled, performance-intensive environments operating to a 24/7 support model - Expert-level Linux administration, especially Ubuntu distributions - Proficiency in system tuning, disk I/O optimization, and hardware-level performance tweaks - Familiarity with Out of Band management tools (IPMI, Redfish, PXE, etc.) - Strong networking fundamentals: TCP/IP, DNS, DHCP, VLANs, routing, switching - Strong experience with infrastructure scripting and automation (Bash, Python, Ansible) - Deep understanding of observability principles and tools (Prometheus, Grafana) - Hands-on experience operating orchestration platforms (Kubernetes, MAAS, Tinkerbell) - Strong grasp of ITSM and service operation best practices - Excellent communication and mentorship skills - Comfortable interfacing with internal stakeholders and external customers - Bonus: Knowledge of HPC workloads and GPU-based infrastructure - Bonus: Experience with InfiniBand networks and HPC performance tuning Nice to have: - Bachelor or Masters Level degree in Computer Science, Engineering or related field, or equivalent experience. - LPIC Certifications - ITIL Foundation level qualification or equivalent experience How you work: - You approach problems with a systems mindset - balancing practical execution with long-term scalability - You elevate the team, setting high standards for technical quality and engineering excellence. - You hold yourself and others accountable - giving direct feedback and expecting the same - You take initiative, owning