Senior System Administrator

As a Senior System Administrator (m/f/d), your mission is to ensure the reliability, security, and scalability of our cloud-based infrastructure while driving operational excellence through automation and modern infrastructure practices. You will play a key role in maintaining and evolving our Linux-based environments, ensuring that systems remain resilient, secure, and highly available.

In this role, you act as both a technical expert and a strategic contributor. You continuously identify opportunities to automate repetitive tasks, improve system observability, and enhance deployment reliability. By strengthening our containerized infrastructure and optimizing CI/CD processes, you help accelerate development workflows while maintaining strong operational standards.

You will work closely with engineering, product, and data teams to ensure that infrastructure supports the company’s growth and product delivery needs. At the same time, you champion infrastructure best practices, ranging from system hardening and patch management to monitoring, disaster recovery, and performance optimization.

Ultimately, your mission is to build and maintain a robust, secure, and automated platform that empowers teams to deliver reliable products efficiently and safely.

Key Responsibilities

Infrastructure Reliability and Container Operations

Ensure the stability, availability, and performance of our Linux- and mainly AWS-based infrastructure and containerized environments. Manage and optimize Docker deployments and maintain CI/CD pipelines using TeamCity to support reliable, automated application delivery.

Automation and Configuration Management

Design, develop, and maintain infrastructure automation primarily using Ansible. Continuously improve configuration management, provisioning, and operational workflows to reduce manual processes and increase system reproducibility.

Security, Hardening, and Observability

Implement and maintain strong security standards across all systems. Perform Linux system hardening, deploy and manage security tools, and maintain monitoring, logging, and alerting solutions to ensure visibility, threat detection, vulnerability scanning and proactive issue resolution.

Public Key Infrastructure and Secrets Management

Operate and evolve our internal PKI, including the management of our internal Certificate Authority and certificate lifecycle processes. Maintain and improve our PGP/GPG-based email encryption setup, with the opportunity to design and roll out an internal key server. Consolidate and harden our diverse secrets management landscape - spanning AWS Secrets Manager, Ansible Vault, Docker Secrets, KeePassXC, and Passbolt - to establish consistent practices, clear ownership, and secure handling of credentials across the organization.

Change Management and System Optimization

Manage system changes including patching, upgrades, and infrastructure improvements. Continuously evaluate and optimize system and network performance while ensuring controlled, reliable change processes.

Incident Response and Business Continuity

Provide Tier 2/3 operational support for infrastructure incidents during working hours. Contribute to root cause analysis and continuously improve incident response procedures, disaster recovery plans, and business continuity strategies.

Cross-Team Collaboration

Collaborate closely with Product, Data, and Engineering teams to support data delivery, deployment needs, and infrastructure improvements. Contribute to internal initiatives that mature and streamline core services across the organization.

Mobile Device Management (MDM)

Design, implement, and maintain a Mobile Device Management system to support secure and scalable device administration. Plan and execute the rollout of managed devices, define security policies, and ensure compliance with company standards for mobile and endpoint devices.

Do you have experience in macOS?, * At least 5 years of experience administering Linux- or Unix-based production environments and infrastructure.

• Strong expertise in Linux system administration, networking fundamentals, virtualization, and container technologies (Docker and Kubernetes).
• Experience with administrating and managing cloud environments (AWS, Azure).
• Identity and access management experience (LDAP, SSO, IdP integrations).
• Solid scripting skills (ideally Python and Bash) with experience maintaining and modernizing operational scripts.
• Strong understanding of infrastructure security, including Linux hardening and security best practices following frameworks such as ISO 27001, CIS Benchmarks, DISA STIGs, BSI IT-Grundschutz or similar.
• Experience implementing and maintaining monitoring, logging, and alerting systems for infrastructure observability, ideally with Elasticsearch, Prometheus and Grafana.
• Experience managing system lifecycle processes including patching, upgrades, and controlled infrastructure changes.
• Experience implementing or operating Mobile Device Management (MDM) solutions on macOS, iOS and Android, and supporting secure device rollouts.
• Experience with incident response, root cause analysis, and improving operational resilience.
• Experience with typical project management tools, ideally Atlassian.
• Fluent English (C1 or higher); German is a plus.

Preferred Qualifications

• Practical experience operating and maintaining PostgreSQL databases in production environments.
• Hands-on experience building and maintaining CI/CD pipelines (e.g. TeamCity or similar) and using infrastructure-as-code tools such as Ansible.
• Relevant certifications such as RHCE, LFCS, or security certifications like OSCP/CISSP are a plus
• Experience working in collaborative engineering environments with git version control and modern DevOps workflows.

Pulled from the full job description

• Flexible schedule, * A competitive gross annual salary ranging from €60K-€80K, based on experience and expertise.
• Up to 100% remote work opportunity.
• Provision of MacBook and peripherals for remote work setup.
• Flexible working hours, with full-time or part-time options (30h-37.5h per week).
• Six weeks of paid annual leave.
• A comprehensive educational package to support your professional development.

Semalytix (https://www.semalytix.com/) is pioneering patient-centric decision-making and treatment through comprehensive analysis of millions of real-world data points. Our multidisciplinary team combines expertise from Artificial Intelligence, Machine Learning, Linguistics, Life Sciences, Pharmaceuticals, and SaaS start-ups, committed to enhancing lives with superior decision-making tools. Founded in 2015 with headquarters in Bielefeld, Germany, Semalytix is a VC-funded enterprise with a dynamic and dedicated team of about 30 members, serving three top-10 Pharma customers.