Linux System Administrator (Wrocław, hybrid)

About the role.

We're hiring a mid-level Linux System Administrator in Wrocław 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: Wrocław, Poland. Hybrid: remote + office in Wrocław, flexible office days. We’re looking for someone based in or near Wrocław (or willing to relocate).

Contract: B2B with DomainCrawler AB, Sweden

Rate: 3,000–3,500 EUR net per month (B2B invoice)

Travel: Stockholm, several times a year , costs covered

DomainCrawler 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 DomainCrawler 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.