Infrastructure Engineer (Linux Platforms)

Colt provides network, voice and data centre services to thousands of businesses around the world, allowing them to focus on delivering their business goals instead of the underlying infrastructure. Why we need this role The Infrastructure Engineer designs, builds, automates, tests and operates secure Linux-based infrastructure supporting critical telecommunications network services. Working from agreed architectural and engineering standards, the role deploys and maintains platforms supporting DNS, routing, identity, authentication, monitoring, observability and network-management capabilities. The Engineer is responsible for reliable implementation, infrastructure automation, lifecycle maintenance, monitoring, incident resolution and continuous improvement. The role works across Network Engineering, Security, Infrastructure, Architecture and Operations and progressively develops ownership of defined platforms and services. The role supports a distributed estate of hundreds of Linux systems across critical network, security, operational and business services. Platforms and Services The team designs, deploys, automates and maintains Linux infrastructure supporting: • Authoritative, recursive and caching DNS services. • Route reflectors and other routing control-plane services. • Authentication, authorisation and accounting services. • Identity management, directory and privileged-access integrations. • Network observability, telemetry, logging and monitoring platforms. • Network-management and automation services. • Virtualised and, where appropriate, containerised infrastructure. • Supporting services such as NTP, PKI, certificate management, secure repositories and configuration services. What you will do Platform Engineering and Delivery • Build, configure, test and maintain Linux platforms using distributions such as RHEL and Ubuntu. • Implement infrastructure from approved architecture, high-level designs, low-level designs and engineering standards. • Execute platform deployments, upgrades, migrations, patching and decommissioning activities. • Maintain accurate configuration, asset, dependency and lifecycle records. • Participate in design reviews and identify practical improvements to platform standards and implementation approaches. Network-Critical Services • Deploy and maintain DNS platforms and support resolution, delegation, availability and security troubleshooting. • Build and maintain Linux hosts supporting route reflectors and other routing control-plane services under approved network designs. • Deploy and support authentication, authorisation, accounting, identity and directory services, including Red Hat and Oracle LDAP environments. • Implement and maintain network observability, telemetry, logging, monitoring and network-management platforms. Automation and Efficiency • Develop and maintain automation using Ansible, Bash or Python and infrastructure-as-code principles. • Identify repetitive operational activities and implement approved automation to reduce manual effort and error. • Maintain consistent, reusable configuration and build standards across environments. Operations, Reliability and Lifecycle • Monitor platform service health, performance, capacity, availability and resilience. • Implement health checks, dashboards, logs and actionable alerts as part of each platform deployment. • Investigate incidents and alerts, contribute to root-cause analysis and implement agreed corrective actions. • Test backup, restoration, failover and recovery procedures and record the results. • Support platform currency, vulnerability remediation, upgrade and obsolescence plans. Security and Compliance • Implement and validate platform hardening in line with approved standards, including CIS-aligned controls where applicable. • Maintain vulnerability remediation, access controls, secrets, keys, certificates and centralised audit logging. • Produce and maintain evidence for internal controls, audit and compliance activities. • Support security investigations and preserve relevant operational and forensic evidence. • Escalate unsupported, end-of-life or non-compliant components and support agreed remediation plans. Collaboration and Documentation • Work with Network Engineering, Security, Infrastructure, Architecture, Operations and application teams. • Produce and maintain implementation records, technical documentation, support models and operational runbooks. • Share knowledge, contribute to team capability and progressively take ownership of defined services or technical components. Operational Support • Participate in the Infrastructure Operations on-call rota supporting priority incidents. What we're looking for Required Skills and Experience • Typically three to five years of experience in Linux administration or infrastructure engineering within enterprise or service-provider environments. • Strong practical experience with enterprise Linux distributions, particularly RHEL and Ubuntu; experience with CentOS or successor-compatible distributions is beneficial. • Experience with Ansible, Bash or Python scripting, configuration management and infrastructure-as-code principles. • Working knowledge of TCP/IP, IPv4 and IPv6, DNS, routing principles and BGP. • Working knowledge of network segmentation, firewalls, load balancing, NTP, PKI, TLS, certificates, authentication and identity services. • Experience implementing monitoring, logging, alerting, backup, recovery and high-availability controls. • Understanding of platform hardening, vulnerability remediation and CIS or ISO-aligned security practices. • Strong troubleshooting, documentation, communication and teamwork capability. Desirable Skills and Knowledge • Experience supporting DNS, routing infrastructure, AAA, identity, network-observability or network-monitoring platforms. • Virtualisation platforms such as VMware and KVM. • Containerisation technologies such as Docker or Podman and understanding of Kubernetes concepts and operational practices. • Enterprise storage technologies such as SAN and NAS. • Experience with database environments. • On-premises and cloud platforms such as Microsoft Azure or Google Cloud Platform. • Basic Windows Server awareness. Leadership and Behaviours • Ownership: takes responsibility for assigned work and service outcomes. • Technical capability: builds strong Linux and network infrastructure engineering expertise. • Delivery focus: executes work reliably, safely and to agreed quality standards. • Collaboration: works effectively within and across teams. • Communication: documents work clearly and communicates risks and issues promptly. • Adaptability and continuous improvement: responds well to operational challenges and seeks opportunities to improve services and processes. Preferred Qualifications / Education and Experience • Degree in Computer Science, Network Engineering or a related discipline, or equivalent relevant industry experience. • RHCSA, RHCE, LFCS or a similar certification is beneficial or may be in progress. • Relevant network, virtualisation or security certifications are also beneficial. Summary Linux and network infrastructure engineering role focused on the secure build, automation, operation, monitoring and lifecycle improvement of platforms supporting critical telecommunications network services. What we offer you: Looking to make a mark? At Colt, you’ll make a difference. Because around here, we empower people. We don’t tell you what to do. Instead, we employ people we trust, who come together across the globe to create intelligent solutions. Our global teams are full of ambitious, driven people, all working together towards one shared purpose: to put the power of the digital universe in the hands of our customers wherever, whenever and however they want. We give our people the opportunity to inspire and lead teams, and work on projects that connect people, cities, businesses, and ideas. We want you to help us change the world, for the better. Diversity and inclusion Inclusion and valuing diversity of thought and experience are at the heart of our culture here at Colt. From day one, you’ll be encouraged to be yourself because we believe that’s what helps our people to thrive. We welcome people with diverse backgrounds and experiences, regardless of their gender identity or expression, sexual orientation, race, religion, disability, neurodiversity, age, marital status, pregnancy status, or place of birth. Most recently we have: Signed the UN Women Empowerment Principles which guide our Gender Action Plan Trained 60 (and growing) Colties to be Mental Health First Aiders Please speak with a member of our recruitment team if you require adjustments to our recruitment process to support you. For more information about our Inclusion and Diversity agenda, visit our DEI pages . Benefits Our benefits support you through all parts of life, for both physical and mental health. Flexible working hours and the option to work from home. Extensive induction program with experienced mentors and buddies. Opportunities for further development and educational opportunities. Global Family Leave Policy. Employee Assistance Program. Internal inclusion & diversity employee networks. A global network When you join Colt you become part of our global network. We are proud of our colleagues and the stories and experience they bring – take a look at ‘Our People’ site including our Empowered Women in Tech.