Senior IT Administrator / Senior System Engineer (M/F/D) | Cologne

Flexible working hours, modern infrastructure, hybrid working, and a team that truly lives responsibility – we are looking for a personality to take on technical responsibility for our IT administration, actively develop our infrastructure, and shape IRIS's technological future. You won't just be working on day-to-day operations, but will also be driving key future projects such as building a decentralized infrastructure and a highly available system landscape.

Tasks

As part of our IT team, you will play a central role in operating and further developing our infrastructure. You don't think in tickets, but in solutions, take responsibility, and drive topics forward independently.

Approximately 60% of your time will be spent on projects and modernization, while 40% will be dedicated to operating and optimizing our existing systems.

Your responsibilities include in particular:

• Technical responsibility for our IT administration
• Support, optimization, and further development of our Linux infrastructure
• Operation and expansion of our virtualization platform based on Proxmox
• Administration of our network and firewall infrastructure (pfSense)
• Planning and further development of hybrid infrastructures (on-premise & cloud)
• Setup and maintenance of secure site-to-site and cloud VPNs
• Monitoring of our infrastructure and proactive error analysis
• Analysis and resolution of technical disruptions
• Further development of automation and standardization processes
• Technical evaluation of new requirements and derivation of sustainable infrastructure decisions
• Documentation and continuous improvement of our system landscape

What you can look forward to

In the coming months, you will actively shape the following projects, among others:

• Building a decentralized IT infrastructure
• Introduction of a highly available infrastructure (HA cluster)
• Further development of our Linux and Proxmox platform
• Expansion of the network and security architecture
• Further automation of our infrastructure

You will not only work on individual components but also shape the technical direction of our company in the long term.

Qualification

What you should bring

• Several years of professional experience as an IT administrator, system engineer, or in a comparable role
• Several years of professional experience in Linux administration
• Experience with virtualization, ideally Proxmox
• Sound understanding of networks (routing, VLANs, DNS, DHCP, VPN, firewalling)
• Basic knowledge of Bash, Python, or Ansible
• Experience with monitoring solutions (e.g., Prometheus, Grafana, Checkmk, or Zabbix)
• Very good German and English skills, at least C1 level; ideally native German speaker
• Confident demeanor and the ability to clearly explain technical decisions

What we appreciate additionally

• Experience with pfSense or comparable firewall solutions
• Experience with hybrid infrastructures
• Docker or LXC
• Backup, storage, or high availability solutions
• Experience with cloud platforms (e.g., AWS, Azure, Hetzner)
• Knowledge in IT security and hardening
• Experience with documentation and structured change management

Benefits

What we offer you

• Technical responsibility for our IT administration
• High degree of creative freedom in technical decisions
• Direct influence on our infrastructure strategy
• Approximately 60% project work instead of purely operations
• Short decision-making paths without corporate structures
• Flexible working hours
• Hybrid working
• Modern Linux-based infrastructure
• Individual training and development opportunities
• Flat hierarchies and a collegial team
• Permanent employment contract

Your onboarding
Of course, we won't leave you on your own.
You will receive a structured introduction to our systems and processes. Together with the team, you will get to know our infrastructure and gradually take on responsibility for your area.

Why IRIS?

We believe that good IT emerges where people take responsibility and develop solutions together.
With us, you have the opportunity not only to operate but also to actively shape. Your work is visible, your decisions have an impact, and your ideas are explicitly welcome.

Our locations: Cologne Ehrenfeld and Karlsruhe Durlach: Both offices have good connections to the highway and public transport. The theme of sports is present everywhere in our offices – in the decoration as well as in the interpersonal interactions. All office spaces are shared and available individually for the workday via a booking system. For this position, we are explicitly looking for applicants from the Cologne area only.

Authentic is more important to us than perfect

We know: Artificial intelligence is a natural part of many things today – including applications. That's perfectly fine with us.

Feel free to use AI for support. What really interests us is you: your way of thinking, your experience, and your standard for good IT. Your application doesn't have to be perfectly formulated – it's more important that it's authentic.

After all, we're not looking for a perfect CV, but a personality who takes responsibility and wants to make things better.

We welcome applications from people with diverse backgrounds, experiences, and life paths. For us, personality, motivation, and competence count – regardless of gender, age, origin, religion or belief, disability, sexual orientation, or identity.

Sounds like your next job?
Then we look forward to getting to know you!
Even if you don't meet every requirement 100%, we look forward to your application. Motivation, attitude, and willingness to learn are often more important to us than a complete tech stack.

We look forward to your application

Your contact person: Isabella Gimber

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