System Administrator (Defence & Security)

About the role

Reaktor’s Defence & Security Unit is seeking a System Administrator to join its internal IT team in Helsinki. You will help build and maintain secure, automated environments that support critical development work.

Key responsibilities

• Build and maintain internal IT systems for high‑performing development.
• Develop and improve automation for system maintenance using state‑of‑the‑art tooling.
• Ensure environments are safe, compliant and reliable.
• Collaborate with consultants, developers and stakeholders to solve complex challenges.
• Resolve hardware, network and automation issues and document practices.
• Drive continuous improvement and long‑term infrastructure planning.

Required profile

• Minimum 5 years of system administration or IT infrastructure experience.
• Strong knowledge of Linux (Fedora, CentOS or similar).
• Understanding of IP networking, VPNs and firewalls.
• Familiarity with certificate management and authentication mechanisms.
• Hands‑on scripting experience (Bash, Python, PowerShell, etc.).
• Fluent in Finnish and English, willing to work 100% on‑site.
• Finnish citizenship required for security clearance.

Required skills

• Linux
• IP networking
• VPN
• Firewalls
• Certificate management
• Authentication mechanisms
• Bash scripting
• Python
• PowerShell
• Ansible (nice‑to‑have)
• Windows desktop administration (nice‑to‑have)
• macOS desktop administration (nice‑to‑have)
• TypeScript (nice‑to‑have)
• Go (nice‑to‑have)

What we offer

• Opportunity to support critical security‑focused projects.
• Freedom to choose technologies and methodologies.
• Strong community and support for personal development.
• Career development through guidance and courses.
• Work‑life balance benefits such as car share, child‑care services and hobby clubs.