Senior Infrastructure Engineer

Work on Technology That Protects What Matters
At SiXworks, we build secure digital solutions that support Defence and National Security missions. Our teams work on complex problems where reliability, security, and speed of innovation matter.
We’re looking for a Senior Infrastructure Engineer who enjoys solving difficult technical challenges and wants their work to have real operational impact.
This role requires the highest level of UK security clearance.
What You’ll Do
As a Senior Infrastructure Engineer, you’ll help design, build, and deliver secure digital solutions in highly secure environments. You’ll work alongside engineers, architects, and delivery specialists to develop technology that enables faster, safer decision-making for critical operations.
Your work may include:
Maintain, improve, and secure SiXworks’ multi-classification, virtualised, collaboration and development environments.
Work with IT infrastructure colleagues to improve SiXworks’ ‘Secure by Design’ capabilities, internally and across its projects.
Provide Infrastructure support to SiXworks’ public cloud SaaS offerings (Office 365) as well as project-based systems (public, private and hybrid clouds) in implementation and support lifecycles.
Perform maintenance tasks on the infrastructure through change control.
Assist with monitoring and management of SiXworks’ and project-based ticketing and alerting systems for new changes and security alerts.
Triage monitoring alerts and perform appropriate action.
Maintain monitoring components in line with infrastructure developments.
Ensure all platforms are patched in line with provider recommendations and SiXworks security policy.
Quickly and accurately assess impact of incidents, initiate return to service and ensure follow up actions are completed.
Identify trends and problems and plan changes to improve stability and performance.
Maintain cutting edge knowledge and skills in the design and build of secure public, private, and hybrid cloud and network technologies.
Develop personal knowledge through study/research toward vocational certifications in relevant technologies/vendors.
Advise customers and project teams on infrastructure and support aspects.
Cascade knowledge through knowledge articles for the team and wider organisation.
Support the SiXworks team in winning business.
What We’re Looking For
We value people who take ownership, think critically, and enjoy working as part of a collaborative team tackling complex challenges. You don’t need to tick every box, but we’re particularly interested in people with skills/experience in:
Team Player
Windows Server 2016+ administration.
RedHat Openshift
Linux (CentOS/RedHat/Ubuntu)
EUD provisioning (Autopilot), maintenance, patching and hardening.
SSO – concepts and operation.
Understanding of working in protectively marked environments.
VMware
Azure
Networking
Automation (scripting ansible/powershell)
Kubernetes administration e.g. VMware TKGI
VMware vSphere/vCenter/VCF.
Azure/Microsoft 365 administration.
DevSecOps Tooling
Elastic
Nessus
Application Packaging
HashiCorp Terraform
HashiCorp Vault
Experience working in Agile sprints
Just as important are curiosity, strong problem solving ability, and the motivation to continuously improve how technology is designed and delivered.
About SiXworks
SiXworks is a specialist digital innovation partner delivering secure, mission-critical technology to Defence and National Security organisations. We focus on digital experimentation, secure-by-design architecture, cloud technologies, and rapid application development to help our customers move faster and stay ahead of evolving challenges.
Our team combines expertise from across technology, business, and operational backgrounds including the armed forces creating a collaborative environment where practical thinking and innovation thrive.
Why Join Us
Our culture is guided by six principles: Agility, Security, Innovation, Quality, Collaboration and Inclusivity our North Star for how we work. SiXworks is a leading provider of secure digital solutions, specialising in digital experimentation and focused on fail-safe-fast cutting-edge technology solutions deployed in highly secure environments.

Employment type
Full-Time

Work arrangement
No