Senior Systems Administrator (Linux)

About Bluestaq Limited Bluestaq starts with our people. We are looking for teammates who THINK strategically, SERVE the mission and LEAD from wherever they stand. If you bring curiosity, ownership and a thirst for delivery, we would like to hear from you. Every society runs on invisible systems; Bluestaq is that, for data. Bluestaq Ltd is the UK sovereign subsidiary of Bluestaq LLC (Colorado Springs, USA), and we build the secure data infrastructure that allied operations depend on: mission-critical solutions, flowing through thousands of global users, from ingest to publication in milliseconds, for customers spanning the NATO, Five Eyes and wider allied partners. We are in our formative years in the UK, building on proven foundations in the USA and Australia. That means real opportunity, early: decisions at your level, and colleagues who know their craft and trust you to know yours. The Role You will own specific Linux systems supporting our NATO delivery on AWS, from configuration and monitoring to upgrades and incident response. You will be the specialist the team escalates to when a fault defeats first-line troubleshooting, and you will improve reliability as well as restore it. You will mentor Systems Administrators in troubleshooting and operational hygiene. This is an individual contributor role with no direct reports, reporting to the Systems Administration Manager, with a clear technical path to Lead Systems Administrator. What You Will Do • Own one or more systems or environments, covering configuration, monitoring and alerting, upgrades and incident response. • Debug difficult faults, including performance problems, resource exhaustion and integration failures, and take each incident from first symptom to a root cause and a remediation plan that holds. • Configure and tune services with secure, hardened defaults, and turn scan output and logs into lasting remediation. • Plan and execute upgrades and changes under change control, with realistic risk assessment and a tested rollback. • Act as the escalation point for Systems Administrator colleagues, mentor them, and document patterns others can reuse in runbooks and standard operating procedures. • Work across engineering, cyber and data teams on cross-functional problems. • Take part in UK operational coverage, including on-call rotation and structured handovers with the US team. What You Bring • Strong hands-on Linux systems administration in complex, secure production environments, with depth in service behaviour, performance tuning and hardened configuration. Experience on Microsoft Azure, VMware vSphere or similar platforms is transferable. • Sound networking fundamentals, including DNS, DHCP, VLANs, firewalls and routing, and hands-on identity and access management across directory services and cloud platforms. • Working experience with automation and infrastructure-as-code tooling such as Ansible, Terraform, Kubernetes, Docker or Packer, and with patching discipline and configuration compliance in an accredited environment. • Curiosity and incident discipline: you diagnose faults under pressure, find the root cause, and record what you found as well as what you fixed. • Experience owning systems, escalating only genuinely novel problems, and mentoring less experienced colleagues deliberately. • Clear written and verbal communication, including when the news is bad, and confident use of ITSM workflows and platforms such as Confluence and Jira. • Judgement with AI tools: applying them where they help, reviewing what they produce and handling sensitive data responsibly. Essential Conditions • Right to work in the UK. • Ability to meet the security requirements above. • Willingness to work 10-hour shifts on a four-on, four-off rota, including w