Linux System Engineers in London

CGI was recognised in the Sunday Times Best Places to Work List 2025 and has been named one of the 'World's Best Employers' by Forbes magazine. We offer a competitive salary, excellent pension, private healthcare, plus a share scheme (3.5% + 3.5% matching) which makes you a member not just an employee. We are committed to inclusivity, building a genuinely diverse community of tech talent and inspiring everyone to pursue careers in our sector, including our Armed Forces, and are proud to hold a Gold Award in recognition of our support of the Armed Forces Corporate Covenant. Join us and you'll be part of an open, friendly community of experts. We'll train and support you in taking your career wherever you want it to go.

CGI’s Space, Defence and Intelligence business unit focuses primarily on the delivery of contemporary and innovative technical solutions for the government agencies' most challenging problems. We work, build, and operate bespoke, technically complex, mission-critical systems which help our clients keep us all safe and secure. We are currently looking for an experienced System Engineer to join our cross-functional team who, in partnership with our clients, will help define, guide and assure the delivery of integrated solutions. The role offers fantastic opportunities to work within an interesting and highly rewarding environment. We are heavily committed to developing our members and provide excellent learning and development opportunities to ensure that your knowledge and skills keep pace with the evolving technology landscape. We engender a culture of innovation, collaboration and ownership; highly motivated self-starters thrive within our organisation.

Due to the secure nature of this project, this role requires candidates to either already hold, or be eligible to obtain, a high level of UK Security Clearance. To meet the eligibility criteria for this clearance, applicants must be sole British nationals, have been resident in the UK for the past 10 years, and must not have spent more than 28 consecutive days outside the UK within the last five years. Individuals who do not currently hold clearance are still encouraged to apply and will be considered both for this position and for other suitable opportunities within CGI where appropriate.

This role is primarily based on a secure client site and requires attendance on site five days per week due to the sensitive nature of the work and the systems involved. While the position is predominantly site-based, there may be occasional flexibility where business needs and security constraints allow. Any such arrangements would be agreed in advance with the project team.

Candidate Profile

In this role, you will support and enhance secure Linux environments across production and non-production systems, ensuring reliability, performance, and security. You will take ownership of diagnosing issues, improving deployment efficiency, and maintaining platforms that underpin highly sensitive operations. You will also work closely with clients and CGI teams to support cloud and security transformation initiatives. This includes contributing to hybrid cloud strategies and helping evolve environments towards modern security models, while being supported by experienced colleagues in a collaborative setting.

Key Responsibilities Include

• Diagnose & Resolve system issues across production and non-production Linux environments
• Administer & Maintain enterprise Linux systems, ensuring stability and performance
• Optimise & Automate deployments to improve efficiency and reliability
• Support & Enable cloud adoption, hybrid architectures, and migration activities
• Contribute & Implement security improvements, including zero-trust approaches
• Collaborate & Advise clients and internal teams on best practices and improvements

Required Qualifications To Be Successful In This Role

You will have hands-on experience administering Linux systems in secure environments, with a proactive mindset and strong troubleshooting skills. You are comfortable working closely with clients, contributing to modernisation initiatives, and continuously developing your technical capability.

Essential Qualifications

• At least 2 years' experience as a Linux Systems Administrator
• Strong hands-on expertise with enterprise Linux distributions (Red Hat, CentOS, Ubuntu)
• Proficiency with Linux command-line tools and shell scripting
• Experience with system monitoring, patching, performance tuning, and automation
• Proven ability to troubleshoot issues and perform root cause analysis
• Working knowledge of networking concepts in Linux environments
• Experience with security hardening and secure system configurations
• Exposure to cloud, virtualised infrastructure, or infrastructure-as-code tools is advantageous
• DV Security Clearance (or willingness and eligibility to obtain) and sole UK nationality