Responsibilities: Enhance, optimize, administer, support, and monitor our Windows and Citrix-based Cloud Hosting Infrastructure, working under the supervision of our Cloud Architect. Provision and maintain customized virtual servers and other infrastructure and compute resources based on customer requirements. Ensure SLAs for uptime are met. Provide end-user support and problem resolution. Participate in rotating off-hours on-call support. Requirements: At least 5 years of experience with administering, configuring, optimizing, and maintaining Windows-based networks, including strong experience with Active Directory, Exchange, and Windows Security. Extensive experience with Citrix server and desktop virtualization products, especially XenServer, XenApp, and XenDestop. Experience with routers, switches, and SANs are desirable, especially HP Layer 3 Switches and Nexenta-based SAN solutions. Self-motivated, able to work with limited supervision. Excellent time management, organized, and strong verbal and written skills.