Linux - System Administrator (f/m/d) Defense Products

About the Position

Linux - System Administrator (f/m/d) Defense Products

At IONOS, we shape the digital future for more than 6.2 million customers worldwide with our solutions. As Europe's leading hosting provider and a pioneer in independent cloud solutions, we are building next-generation infrastructure – from sovereign cloud architectures and high-performance GPU clusters to integrated AI automation tools.

We are looking for a highly motivated System Administrator to join our Defense Platform Services team in Karlsruhe or Berlin. You will be part of a distributed, international team of experts dedicated to combating cybersecurity threats. Your role will be crucial in protecting our hosting products and infrastructure, encompassing classic DDoS mitigation, modern Web Application Firewalls (WAF), Zero Trust strategies, and our Content Delivery Network (CDN).

Responsibilities

• Active Defense & DDoS Mitigation: Administer and troubleshoot scrubbing platforms and a complex, large-scale proxy infrastructure. You will engage in the "cat and mouse game" of fighting attacks in real-time-identifying, washing, and neutralizing malicious traffic to protect core cloud and fiber services.
• Architectural Density & Operational Excellence: Manage the lifecycle of 800+ Linux-based components within a highly available infrastructure. Ensure 24/7 group-wide protection with a mandatory on-call service rotation of one week per month.
• Innovation & Data-Driven Defense: Leverage modern AI tools for log analysis and pattern detection. Utilize the ELK Stack and ClickHouse to manage high-volume telemetry, identify attack signatures, and devise advanced mitigation strategies.
• Lifecycle & Pipeline Management: Develop and optimize CI/CD pipelines in an agile DevOps environment. Evaluate and integrate new technologies-including Docker and Kubernetes-to ensure our defense architecture remains lean, efficient, and ahead of evolving industry threats.

Requirements

• Expert-level proficiency in managing complex, distributed Linux environments.
• Proven experience configuring Nginx as a reverse proxy or Web Application Firewall (WAF).
• Practical knowledge of BGP, Flowspec, and Anycast routing.
• A passion for eliminating repetitive tasks through Ansible, Puppet, and Python.
• Several years of experience in the administration of complex, distributed Linux systems.
• Strong analytical skills to evaluate DDoS attacks, implement effective countermeasures, and continuously develop our defense platforms.
• Initial experience with technologies such as Docker, Kubernetes, ClickHouse, or the ELK Stack is beneficial.

We Offer

• Hybrid working model.
• Flexible working hours through trust-based working hours.
• Subsidized canteen and various free drinks at select locations.
• Modern office space with excellent public transport connections.
• Various employee discounts for activities and products.
• Employee events such as summer and winter parties, as well as workshops.
• Numerous training and development opportunities.
• Various health offerings, such as sports and wellness courses.

About the Company

At IONOS, we don't just manage servers – we shape the digital future for more than 6.2 million customers worldwide with our solutions. As Europe's leading hosting provider and a pioneer in independent cloud solutions, we are building next-generation infrastructure – from sovereign cloud architectures and high-performance GPU clusters to integrated AI automation tools.

What drives us is digital sovereignty for Europe and real impact for small and medium-sized businesses (SMBs) as well as large enterprises. We work in agile teams, rely on transparent structures, and believe that excellence and innovation only emerge through true team spirit.

Ready for your next step? Become part of IONOS and grow with us.

Application Note

We value diversity and welcome all applications – regardless of, for example, gender, nationality, ethnic or social origin, religion, disability, age as well as sexual orientation and identity, physical characteristics, marital status or any other irrelevant factor subject to applicable law.