Lead System Administrator - Defence & Security

Reaktor; Helsinki; Hybrid; EUR 90,000 - 120,000; Full time

Benefits offered by this job

Top-spec computer and phone of yourcho

Phone & internet coverage

Lunch benefit

Extensive occupational healthcare

Family support and parental leave

Comprehensive insurance package

Juice program for open source work

Job summary

Reaktor’s Defence & Security Unit seeks an experienced Lead System Administrator to join our internal IT team in Helsinki. You will own the team backlog, set work priorities, and lead efforts to build and automate a secure, reliable IT environment for DefSec’s development teams.

You will work hands-on across systems, networks, and automation, while collaborating with developers and business stakeholders to align technical priorities with business needs.

Qualifications

• Minimum 8 years of hands-on system administration or IT infrastructure experience.
• Experience gathering requirements, prioritising a team backlog, and balancing conflicting demands.
• Proven ability to align technical work with business needs and communicate with stakeholders.
• Strong written and spoken communication with technical and non-technical audiences.
• Deep knowledge of Linux (Fedora/CentOS or similar).
• Solid understanding of IP networking, VPNs, and firewalls.
• Familiarity with certificate management and authentication mechanisms.
• Scripting experience in Bash, Python, PowerShell, or similar.
• Fluent in Finnish and English (written & spoken).
• Willingness to work primarily on-site in Helsinki.
• Finnish citizenship and security clearance necessary.

Responsibilities

• Own, refine, and prioritize the team backlog to ensure clear direction and steady workflow.
• Set priorities for upcoming work based on business impact, urgency, and dependencies.
• Build and maintain DefSec’s internal IT systems.
• Develop automation for system maintenance and infrastructure management.
• Ensure environments are secure, compliant, stable, and reliable.
• Troubleshoot across hardware, OS, networks, and automation.
• Collaborate with developers, stakeholders, and consultants to translate needs into work.
• Improve documentation and share knowledge within the team.
• Contribute to day-to-day operations and longer-term infrastructure planning.

Skills

Backlog ownership

Stakeholder alignment

Linux administration

Networking & security

Scripting (Bash/Python/PowerShell)

Finnish & English (bilingual)

Communication

Tools

Ansible

Windows administration

macOS administration

Python

Bash

TypeScript

Go

Job description

Reaktor’s Defence & Security Unit is looking for an experienced, hands-on Lead System Administrator to join our internal IT team in Helsinki.

Our team builds and maintains secure and reliable IT environments that DefSec’s development teams depend on. The work ranges from daily maintenance and troubleshooting to automation, security, and longer-term infrastructure development.

As a Lead System Administrator, you will work hands-on as part of the team: building and maintaining systems, developing automation, and solving technical problems. Alongside your technical responsibilities, you will take ownership of the overall flow of the team’s work.

You will keep the backlog clear, bring together technical and business needs, and facilitate prioritisation together with the team and business stakeholders. In our low-hierarchy environment, your role is to help the team maintain a shared understanding of what matters most, navigate competing requirements, and move the right work forward.

What you’ll be doing

• Owning, maintaining, and refining the team’s backlog to ensure clear direction and steady workflow.
• Setting priorities for upcoming work based on business impact, urgency, and technical dependencies.
• Building and maintaining DefSec’s internal IT systems.
• Developing automation for system maintenance and infrastructure management.
• Ensuring that our environments are secure, compliant, stable, and reliable.
• Troubleshooting issues across hardware, operating systems, networks, and automation.
• Working closely with developers, business stakeholders, and consultants to understand and translate their needs into actionable work.
• Improving documentation, sharing knowledge, and developing the team’s technical practices.
• Contributing to both day-to-day operations and longer-term infrastructure planning.

What we’re looking for

• At least 8 years of relevant experience in system administration or IT infrastructure.
• Proven experience in gathering requirements, prioritising a team backlog, and balancing conflicting demands.
• Demonstrated ability to work directly with business stakeholders and align technical priorities with business needs.
• Good communication skills with both technical and non-technical stakeholders.
• Strong knowledge of Linux, such as Fedora, CentOS, or similar.
• Good understanding of IP networking, VPNs, and firewalls.
• Familiarity with certificate management and authentication mechanisms.
• Hands‑on scripting experience with Bash, Python, PowerShell, or similar.
• Fluency in both Finnish and English (written & spoken).
• Willingness to work primarily on‑site in Helsinki.
• This position requires Finnish citizenship due to client and security regulations. The selected candidate must successfully complete a security clearance process.

Nice-to-have skills

• Experience with Ansible or similar automation tools.
• Familiarity with Windows and macOS desktop administration.
• Programming experience in TypeScript, Python, or Go.

For two decades, we’ve been developing qualities and capabilities for adapting, reacting, and supporting change – building Reaktor to hold up in a fast‑paced environment while ensuring the well‑being of our people.

While working at Reaktor, we’ll provide you with

• An opportunity to work with our DefSec’s internal IT team to ensure our consultants have access to secure and efficient environments. Your work directly supports our critical security‑focused software projects.
• The ability to impact how you work. Together with your team, you choose the approach, technologies, and methodologies you think will work best in any given situation.
• A community with as much support as your heart desires.
• A team that’s not only experienced but considerate as well – they all want you to succeed.
• Career development, helping you develop your skills further through guidance and/or courses, and giving you the opportunity to explore your career interests.
• A sustainable work‑life balance and support for your daily life outside of work. (e.g., free moving day, Reaktor car share, sick child care services, office space to use for your private events, etc.).
• Many different hobby clubs, from winter swimming and running to knitting and archery, that bring people together outside of (and sometimes inside) office hours. Many of these are supported by Reaktor.

Interested?

Diversity, equity, and inclusion

Together, we are committed to making Reaktor an environment that embraces and values all of our employees for the whole of who they are. We encourage applicants from all backgrounds to apply, knowing that studies show that members of underrepresented communities don’t apply for jobs unless they fully satisfy all of the requirements. If you’re thinking twice about applying for this reason, we invite you to send us your application anyway. You could be just the person we’re looking for.

Benefits

At Reaktor Helsinki, our benefits and perks evolve with our community, and we’re always open to new ideas that will support the wellbeing of Reaktorians. Currently, we offer the following perks:

Tools

We offer everyone a top‑spec computer and a phone of their choosing to work with and use at work and home. If you need other tools, like a keyboard or a mouse, we’ll figure it out, too!

Phone & internet

To keep you connected, we’ll cover an unlimited phone plan – and a proper internet connection to your home.

We offer the monthly lunch benefit in addition to your salary, which means you only pay the taxes.

Recreational benefit (sports & culture)

At Reaktor, the recreational benefit is an addition to your salary – and it’s tax‑free.

If you want one, we offer an optional commuting benefit card and a bicycle benefit.

Extensive occupational healthcare

Extensive occupational health care services include specialists’ appointments, operations, vaccinations, dental care, and mental health services, including e.g. psychotherapy.

Family support

We support all types of families with encouraging types of parental leave and more, offering support for child care.

An extensive insurance package

Our extensive insurance package safeguards you for accidents, travel, and more.

Our subsidised massage deals keep those shoulders nice and loose.

The Juice‑program enables you to work on open source projects – and get compensated for it!

We’re an equal opportunity employer

All applicants will be considered for employment without attention to race, color, religion, sex, sexual orientation, gender identity, national origin, veteran or disability status.

FAQ

01 What are we looking for?

We believe there’s more that matters than just the resume. We’re looking for an exciting overlap of curiosity, creativity, people skills, and experience: people who are willing to learn, participate, and share new perspectives.

02 What does the hiring process look like?

We take the time to learn about your skills and aspirations and help you learn about ours. Our interview process usually involves three or four conversations over the course of a few weeks. From application to closing, our process takes about four weeks. Your recruiter will keep you up to date on what to expect from each stage of our interviewing process.

03 What kinds of projects do you have?

We do a variety of different kinds of projects, with the aim of each being meaningful and critical to a client’s business. Our typical engagements are from 6 months to 18 months and involve between 3-6 Reaktorians collaborating closely with our clients. When it comes to picking and choosing, we look at a number of things from the business side. For example, we tend to be interested in the multi‑functional growth potential of the project as well as the technological and digital maturity of the client, their product, and the project overall. However, not all good business is a good fit for us culturally. We only take on new business that aligns with our values, is interesting for our people to work on, and has a great local or global impact.

The core idea behind how we staff is that you will never be alone in a project. When staffing our projects, we first start by going through your preferences and ambitions for learning, be it customer location, the field of business, or some particular technology. We then go through your learning and self‑development targets and do our best to match all of the above to a project. We get multiple projects and new openings in existing projects each month. If there isn’t a perfect fit immediately, we try to find a spot for you in an existing project or take some time while you work on internal projects, or get deeper into onboarding.

05 What do people do in between projects?

Client work is our number one priority, but we’ve gotten pretty good at making the most out of the normal in‑between time in the consulting business. Maybe you’ve just joined us, your project has just ended, or you’re rotating out of one and looking for new opportunities, it can sometimes take a while to find the next client project. These are great opportunities to take training, dive into a new topic, or help out with internal development. Your time in between projects does not affect your pay.

06 Is it ok to work remotely?

It depends on the project in question, as we choose the option that fits best with each client. Sometimes projects are multisite, at other times, there are more on‑site visits, and on rather rare occasions, we are 100% remote. That said, we love to see each other every once in a while and spend time together at get‑togethers and occasional in‑person meetings.