DevOps / SRE - On-premise Infrastructure M/F (M/F)

About the role

COISI is a company specializing in the development and management of digital tools and applications in the business travel and expense report sector. Always looking for innovation to offer our clients cutting-edge technological solutions, we take on ambitious technical challenges that accompany our development and our desire to offer tailor-made solutions. COISI is part of the VOYAGEXPERT group, a dynamic international company, number 1 in its market. VOYAGEXPERT is the leading independent business travel agency in France, with more than 200 employees and a presence in 6 countries: France, Germany, Switzerland, Spain, Poland, and Italy. Thanks to an annual growth of 30%, the group offers a stimulating environment and numerous opportunities for development. By joining COISI, you join a human-sized, agile, and innovative structure, while benefiting from the solidity and ambitions of a recognized international group. You will participate in strategic projects at the heart of the digital challenges of business travel. Voyagexpert provides tailor-made tools for business travel on a modern on-premise stack. As part of our development, we are recruiting a DevOps / SRE (M/F) on a permanent contract to join our team based in Nantes and to support the complete execution infrastructure: Proxmox virtualization, Kubernetes clusters, network services, and security. You will be the first person dedicated to the infrastructure, in direct contact with the development team (-10 people). Your voice will count on structural choices. Your missions: - Design and operate Proxmox clusters (hypervisors, storage, network, HA) - Industrialize the infrastructure via Infrastructure as Code (Terraform, Ansible) - Set up and maintain network services: DNS, DHCP, certificate authority (PKI) - Manage secrets and security (Vault, TLS, encryption) - Guarantee the availability and reliability of the multi-tenant platform - Build observability: metrics, logs, alerting (Prometheus, Grafana, Loki) - Design and operate on-premise Kubernetes clusters (deployments, networking, RBAC, observability) - Document, automate, transmit Our stack: - Platform: Proxmox (target), Docker, Kubernetes (target), Linux - Backend: Node.js, pnpm workspaces monorepo, layered architecture - Data: PostgreSQL, Redis, Flyway for migrations - Messaging: RabbitMQ (specific cases) - Secrets & security: HashiCorp Vault - Observability: Prometheus, Grafana, Loki - Reverse proxy: Traefik - CI/CD: GitLab CI Profile sought: - 3 years of experience in DevOps / SRE infrastructure - Real autonomy (you will be the first person dedicated to the infrastructure) - Ability to communicate with developers and the Product Owner - Taste for documentation and transmission - Pragmatic spirit: no over-complexity, defensible choices What we offer: - Full-time permanent contract in Nantes - Remuneration starting from €38k gross annual, depending on profile and experience - Hybrid remote work (2 days of remote work / week) - Human-sized team, strong documentary culture - Real impact: your choices structure the infrastructure for the years to come - Training & monitoring: annual budget for certifications (CKA, CKS, HashiCorp.) and at least one tech conference per year (KubeCon, DevOps D-Day, FOSDEM.), with monitoring time integrated into working hours. - Work environment: quality equipment of your choice and structured onboarding with technical pairing on existing systems and the infra roadmap. Are you ready to take on the challenge? Join us and participate in a technological adventure within a booming group! To learn more: https://www.voyagexpert.eu