Manage day-to-day administration of servers, virtualization, storage, networking and monitoring. Lead incident response for infrastructure and platform issues, run post-incident reviews and track fixes to closure. Own day-to-day administration of production and non-production infrastructure: Windows and Linux servers, VMware virtualization, storage and networking. Set up and maintain monitoring, alerting and dashboards so issues are caught before customers report them. Manage backups and disaster recovery, including regular restore tests and DR exercises. Coordinate with the colocation provider on hardware replacements, remote hands requests, and power and network maintenance. Plan capacity for compute, storage and network, and flag hardware and licence renewals ahead of time. Run the on-call rotation, shift handoffs and weekly status reporting to the client. Maintain runbooks, architecture diagrams, the asset inventory and configuration records. Work with the security and release lead and the DBA on maintenance windows, upgrades and cross-team changes. Find manual tasks that can be automated and move to infrastructure as code where it fits. Must-Have Requirements: 15+ years in infrastructure or systems operations, with at least 3 years leading an operations team or managed service. Strong hands-on experience with Windows Server, Active Directory and VMware vSphere, and working knowledge of Linux. Experience operating production systems in a colocation or on-premises data center. Good knowledge of networking: switching, routing, firewalls, load balancers, DNS and TLS. Experience with monitoring tools such as Datadog, New Relic, PRTG, Zabbix, SolarWinds or Prometheus/Grafana. Experience running incidents, problems and change management for a production service. Willing to work with regular overlap with PST business hours and to be part of an on-call rotation. Clear written and spoken English and comfort reporting to US-based client stakeholders. Nice-to-Have: ITIL v4 Foundation or a similar certification. Experience with Ansible, Terraform or similar automation tools. Experience hosting .NET applications on IIS. Experience supporting a multi-tenant SaaS product.