Linux System Administrator

About the role. We're hiring a mid-level Linux System Administrator to run our on-premise infrastructure: our own physical servers in Stockholm. You'll keep the servers, the operating system and our core services healthy and secure, work alongside our developers, and travel to Stockholm several times a year to install and replace hardware. - Seniority: Mid (3+ years) - Location: Hybrid (remote + office in Wrocław , flexible office days) - Contract: B2B with [компания] AB, Sweden - Rate: 3,000–3,500 EUR net per month (B2B invoice) - Travel: Stockholm, several times a year , costs covered [компания] is a Swedish company that provides structured domain name data to businesses. Our database covers more than 1.4 billion registered and unregistered domains, with a wide range of data on each: DNS, SSL certificates, ownership, hosting, technologies and more. Domain registries and registrars, brand protection agencies and OSINT investigators use it to fight counterfeiting, uncover threats and research markets. Responsibilities: - Monitor the health of the servers and services, and fix issues when they come up. - Patch and update Debian, including major release upgrades. - Keep our self-hosted CI/CD and source control tools running: upgrades, backups runners and agents, plugins. Developers own the pipelines. - Keep the runtime environment for our services working: OS packages, systemd and logs. - Run backups, test restores regularly, and keep the disaster recovery plan up to date. - Manage the network: switches, firewalls, VPN. - Handle security: hardening, vulnerability scanning, and access management (SSH keys, sudo, onboarding and offboarding). - Extend our Prometheus and Grafana monitoring, and bring all servers under configuration management. - Look after hardware: catch failing disks, memory and other components early (SMART, ECC and kernel errors), firmware and BMC updates, RAID health. - Coordinate on-site remote-hands support between visits. - Travel to Stockholm several times a year to install and replace hardware. - Keep documentation up to date: hardware inventory , network diagrams and runbooks. - Work with developers on what they need from the infrastructure, and contribute to capacity planning. Must-have: - 3+ years administering Linux servers in production, with hands-on Debian or Ubuntu experience: apt, systemd, unattended-upgrades and major release upgrades. - Hands-on work with physical servers: racking, cabling, replacing components, IPMI or iDRAC, and both hardware and software RAID. - Networking fundamentals: TCP/IP, VLANs, routing, DNS, firewalls (nftables or iptables). - Configuring managed switches from at least one major vendor. - Configuration management with Ansible or a similar tool. - Prometheus and Graf ana: exporters, dashboards and alerting rules. - Designing backups and testing restores. - Security practice: hardening, patch management, access management. - Administering self-hosted CI/CD tools such as GitLab or Jenkins. - English good enough for documentation and daily communication. - Willingness to travel to Stockholm several times a year and to do physical work such as lifting and racking servers. Nice-to-have: - Enterprise network equipment such as Juniper or Cisco. - OpenVPN, WireGuard or another VPN technology. - Centralized logging (ELK, Loki or Graylog). What we offer: - 3,000–3,500 EUR per month on a B2B contract with [компания] AB, Sweden, paid in EUR. - 24 paid days off per year. - Hybrid work with flexible office days at our Wrocław office. - Travel to Stockholm several times a year, with travel costs covered.