Senior DevOps Engineer OpenSource - C.

About Proximus LuxembourgProximus Luxembourg is a leading historical player in the ICT & Telecoms markets. Proximus Luxembourg addresses both residential and business markets through its commercial brands Tango, Proximus NXT and more recently Codit. With PSF support status, the company has almost 800 employees. All these experts share a passion for digital technology, a spirit of openness and innovation, and a desire to simplify, connect and make their customers' personal and professional activities ever more secure. Proximus Luxembourg is actively contributing to the acceleration of Luxembourg's digitalisation and its economic influence through the development of connectivity, resilient infrastructures and 5G, as well as innovative technologies such as Blockchain, Artificial Intelligence, Machine Learning and IoT. Proximus Luxembourg is a subsidiary of the Proximus group (Euronext Brussels: PROX), provider of digital services and communication solutions operating in the Belgian and international markets. About Proximus NXTProximus NXT Luxembourg supports all organizations in their digital transformation, by providing holistic ICT & Telecommunication solutions, as well as tailored managed services. With our partners and customers, we co-create opportunities and enable growth in a secure and sustainable manner. As a result of our unique expertise in next-gen IT services, mobile and advanced connectivity, we help our customers achieve their ambitions and realize their vision. Together with them and our partners we implement sovereign and trusted solutions that make people work smarter.– www.proximusnxt.lu Your mission:As a Senior DevOps Engineer, you will play a pivotal role in driving our enterprise IT transformation.You will act as the technical backbone for both operational continuity and migration execution, ensuring a seamless transition from our legacy Linux-hosted Atlassian suite (Jira, Jira Service Management, Confluence) to a modern, containerized OpenSource ecosystem (Zammad, OpenProject, and XWiki) deployed on Red Hat OpenShift. In this hybrid role, you will bridge the gap between frontend integration and backend platform reliability. On one hand, you will maintain the existing Atlassian suite. On the other hand, you will actively build the migration tools, custom forms, and integrations required for the new OpenSource stack. This includes developing custom Zammad integration forms to replace Jira Service Management, maintaining API gateways, and configuring workflow orchestration engines. Operating entirely within our enterprise OpenShift environments, you will deploy, tune, and run secure, scalable application instances and gateway services. You will drive infrastructure automation via Terraform and Ansible, implement GitOps practices using ArgoCD, and handle day-to-day platform operations. Finally, you will monitor system health and performance and actively participate in the team's shifts and on-call rotations to guarantee high availability and system uptime throughout the entire migration lifecycle. Technical Skills• Atlassian Automation: Groovy scripting (ScriptRunner), Java development (Atlassian SDK, Hooks, OSGi bundles). • OpenSource Stack: Zammad (forms development, Ruby/API customization), OpenProject, XWiki. • Platform Engineering & Customization: Deep practical experience deploying, tuning, and maintaining Zammad, OpenProject, and XWiki. Ability to build and customize Zammad integration forms using HTML/JavaScript/REST APIs to capture user requests seamlessly. • Infrastructure & Orchestration: Linux system administration (RedHat/Debian), OpenShift/Kubernetes, Helm charts. • Database & Data Migration: PostgreSQL/MySQL, ETL scripting (Python, Bash, or Go) for data extraction from Atlassian databases. • System Knowledge & Troubleshooting: Hands-on ability to troubleshoot mixed technology stacks: debugging Ruby on Rails workers (Zammad/OpenProject), Java/Tomcat engines (XWiki), Redis queues, and Elasticsearch/Solr re-indexing jobs. • OpenShift Administration: Strong engineering skills in managing resources within Red Hat OpenShift, including pods configuration, deployment configs, routes, network policies, and persistent volume claims (PVCs). • API & Workflow Execution: Practical experience with enterprise API Gateways (Kong / Gravitee / Tyk) and workflow engines (n8n). Skilled in setting up routes, webhooks, rate limiting, token validations (JWT/OAuth2), and automated cross-app data routing. • CI/CD, IaC & GitOps: Strong practical knowledge of Terraform, Ansible, GitLab CI, and ArgoCD to automate infrastructure configuration and rapid application deployments. • Enterprise Observability: Robust hands-on experience using Dynatrace to monitor application performance, track custom metrics, analyze logs, and diagnose bottlenecks in containerized applications. • Collaborative Problem Solving: Strong troubleshooting skills under pressure, ability to manage root-cause analysis (RCA), and capability to collaborate effectively across cross-functional developer squads. Key Activities & Responsibilities• OpenShift Stack Deployment: Implement highly scalable, resilient, and performant Zammad, OpenProject, and XWiki deployments across OpenShift clusters based on approved reference architectures. • Forms & Integration Development: Develop and optimize custom frontend integration forms and automate backend data mappings using n8n workflows and API endpoints to replace legacy JSM intake methods. • Pipeline Automation: Build and manage secure CI/CD pipelines in GitLab CI to automate application updates, security patches, database migrations, and multi-environment promotions. • Observability & Maintenance: Configure Dynatrace OneAgent settings, monitor system health, perform day-to-day configuration, log analysis, and system tuning to maintain top platform performance. • Shifts & On-Call Operations: Actively participate in the team’s shift coverage and mandatory on-call rotation to guarantee the ongoing performance and reliability of production systems. QualificationsQualifications/Experience• Bachelor’s or Master’s degree in Computer Science, Information Technology, or a related field. • Minimum of 5 years of experience as a Cloud/DevOps Engineer with a proven track record across the entire DevOps lifecycle. • Demonstrated experience handling end-user applications support, custom API form integrations, and microservices management inside OpenShift. • Professional certifications in Red Hat OpenShift or cloud-native technologies are highly desirable. Requirements• EU citizenship. • Fluency in English (written and spoken) is required; proficiency in any other European language is a plus. • DevOps operational shift patterns (07:00 – 20:00 CET): o Early Shift: 07:00 – 16:00 o Late Shift: 11:00 – 20:00 • On-call rotation (monthly): mandatory rotation covering 7 consecutive days (including weekends).