System Administrator (Defence & Security)
About this role
Reaktor's Defence & Security Unit is looking for a System Administrator to join our internal IT team in Helsinki.
Join Reaktor's DefSec team, where agility, teamwork, and trust drive everything we do. We work on some of the most complex and mission-critical challenges in the industry, helping clients navigate an evolving landscape with cutting-edge solutions.
Are you in your element when maintaining and building secure, automated IT environments that support world-class development work? Do you enjoy solving complex technical challenges hands-on while working alongside dedicated professionals? If so, you might be just the person we're looking for.
What you'll be doing
Systems Installation & Maintenance - Build and maintain DefSec's internal IT systems that enable high-performing development work.
Automation & Infrastructure Development - Maintain and improve automation for system maintenance, using state-of-the-art tooling.
Security & Stability - Ensuring our environments are safe, compliant, and reliable.
Cross-functional Collaboration - Partner with DefSec consultants, developers, and stakeholders to solve complex and multi-dimensional challenges.
Support & Troubleshooting - resolving issues from hardware to networks and automation.
Documentation & Knowledge Sharing - Document practices and systems, and actively share your learnings with the team.
Continuous Improvement - Help evolve our internal systems and support organization, taking ownership of both day-to-day operations and longer-term infrastructure planning.
To thrive in this position, you'll need:
Minimum of 5 years of relevant experience in system administration or IT infrastructure roles.
Strong knowledge of Linux (Fedora, CentOS, or similar).
Understanding of IP networking, VPNs, and firewalls.
Familiarity with certificate management and authentication mechanisms.
Hands-on experience with scripting (Bash, Python, PowerShell, etc.).
A proactive mindset with a focus on helping others and solving p