Lead System Administrator (Defence & Security)

About the role

Reaktor’s Defence & Security unit seeks an experienced, hands‑on Lead System Administrator to join its internal IT team in Helsinki. You will build and maintain secure, reliable environments that support critical security‑focused software projects.

Key responsibilities

• Own and refine the team backlog, set priorities based on business impact, urgency and technical dependencies.
• Build, maintain and automate DefSec’s internal IT systems, ensuring security, compliance and stability.
• Troubleshoot hardware, OS, network and automation issues while collaborating with developers, consultants and business stakeholders.
• Improve documentation, share knowledge and develop the team’s technical practices.

Required profile

• Minimum 8 years of system administration or IT infrastructure experience.
• Proven ability to gather requirements, prioritize work and balance conflicting demands.
• Strong communication skills with both technical and non‑technical stakeholders.
• Fluency in Finnish and English (written & spoken) and willingness to work onsite in Helsinki.
• Finnish citizenship and successful completion of a security clearance.

Required skills

• Linux administration (Fedora, CentOS or similar).
• IP networking, VPNs, firewalls and certificate/authentication management.
• Scripting with Bash, Python and PowerShell.
• Automation tools such as Ansible (nice‑to‑have).
• Familiarity with Windows and macOS desktop administration (nice‑to‑have).

What we offer

• Opportunity to impact critical security projects and choose technologies/methodologies.
• Supportive community, diverse hobby clubs and strong work‑life balance benefits.
• Career development through guidance, courses and exploration of interests.
• Practical perks such as free moving day, car‑share, sick‑child care and office space for private events.