Infrastructure & Systems Administrator Position

Employment type: Full-time, direct hire

Reports to: Head of IT

About the role

Our client is looking for a hands-on Systems Administrator to help manage and secure a diverse, always-on infrastructure stack - spanning virtualisation, databases, web services, telephony, and identity systems. You'll be the person keeping the lights on patching, monitoring, provisioning, and automating so things run smoothly and securely. You'll report to a senior lead, so this isn't a solo on-call role - you'll have support and escalation paths, but you'll own day-to-day operations.

This role suits someone who likes variety - one day you're tuning VLANs and firewall rules, the next you're scripting a backup validation job or rolling out a Windows update to end users. We're looking for a generalist who's comfortable moving across systems, not a specialist in just one - we'll train you on the specifics of our stack (including telephony/VoIP, if that's new to you).

What you'll do

· Monitor & maintain our Proxmox virtualisation cluster (multiple hosts, VM lifecycle, resource allocation) and two Dell SAN storage arrays, using Zabbix and Nagios for alerting and uptime tracking

· Patch & update OS, application, and security updates across Linux and Windows systems on a regular cadence, tracking and remediating vulnerabilities

· Manage networking: VLAN configuration, firewall rules, internal segmentation, and VPN access for remote/hybrid staff

· Administer core services: MariaDB, PostgreSQL/TimescaleDB, ClickHouse, MongoDB, Apache/PHP, Nginx/OpenResty, and Node.js/Python-based internal services

· Support telephony infrastructure: FreePBX, FusionPBX, Tragofone, and OpenSIPS installs - monitoring uptime, applying updates, troubleshooting call quality/routing issues

· Manage identity & access: FreeIPA and Keycloak - user provisioning/deprovisioning, group policies, SSO configuration

· Own backups: verify backup jobs are running, test restores periodically, maintain disaster recovery documentation

· Support end users: Windows desktop environment - account admin, basic troubleshooting, software rollouts and deployment

· Automate: write scripts (Bash, Python, PHP, or similar) and Ansible playbooks to reduce manual, repetitive admin work - patch checks, health monitoring, provisioning, config consistency, reporting

· Document infrastructure changes, runbooks, and standard operating procedures

What we're looking for

We care more about breadth across systems than deep mastery of any single tool - we're happy to train the right person on our specific stack, especially telephony/VoIP. What we need is evidence you've worked hands-on across multiple layers of infrastructure (not just one) and can pick up new tools quickly.

· 3+ years of commercial experience in a similar systems/infrastructure administration role, spanning at least 3-4 of the areas below rather than deep specialization in just one

· Solid Linux administration skills (Debian/Ubuntu or RHEL-family)

· Experience with virtualization platforms (Proxmox VE preferred; KVM/VMware/Hyper-V acceptable equivalent experience)

· Working knowledge of networking fundamentals: VLANs, firewalls, routing, VPNs (WireGuard/OpenVPN/IPsec)

· Comfort administering at least one relational or NoSQL database (MySQL/MariaDB, Postgres, MongoDB, or similar)

· Scripting ability - Bash and at least one of Python, PHP, or Node.js - for automating operational tasks

· Exposure to any configuration management tool (Ansible, Chef, Puppet, or similar)

· Exposure to any monitoring/alerting platform (Zabbix, Nagios, Prometheus, Datadog, or similar)

· Experience supporting Windows desktop environments in a business setting

· Understanding of security best practices: patch management, least-privilege access, credential hygiene

Nice to have

· Exposure to VoIP/telephony systems (FreePBX, FusionPBX, Asterisk, OpenSIPS, or Kamailio) - not expected; full training provided

· Experience with identity providers (FreeIPA, Keycloak, LDAP, or Active Directory)

· Familiarity with SAN storage (iSCSI, multipath, Dell/Compellent/PowerStore or similar)

· Experience with ClickHouse or TimescaleDB for analytics/time-series workloads

· Infrastructure-as-code beyond Ansible (Terraform, Packer)

· Experience with container orchestration (Docker, Kubernetes/k3s) is a bonus, not a requirement

Why this role

· Broad, varied technical exposure - not a narrow, single-stack environment

· Direct mentorship from a senior infrastructure lead

· Real ownership over the systems you maintain, with room to bring in automation and improve processes

Kindly note that by submitting your application for this career opportunity you agree that Guardian Recruiting may use your application for the purpose of the recruitment and selection of the said position and this information may be shared with the relevant stakeholders in the business.

Please note that only shortlisted candidates will be contacted. Should you not have heard back within a two-week period, please assume that your application was unsuccessful.

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