Dennis Johnson
infrastructure
engineer
About
Senior IT Infrastructure Engineer with 25+ years of experience designing, deploying, and managing enterprise environments. Specializing in Windows Server, VMware, Hyper-V/SCVMM, Azure, Cisco networking, and PowerShell automation. Passionate about building AI-powered tools and home lab infrastructure.
Experience
- -
Manager of Enterprise Infrastructure @ Healthcare Organization
US - HybridSummary:
- Leading infrastructure team including System Engineers, Administrators, and Cloud Engineers. Defining enterprise infrastructure direction, managing departmental budget, and driving strategic technology partnerships.
Responsibilities:
- Led physical data center consolidation — reduced from 2 data centers to 1, 8 racks to 2 (75% reduction); implemented Azure hybrid cloud for DR
- Directed enterprise-wide migration from VMware vSphere to Microsoft Hyper-V — consolidated 800 VMs to 350 (56% reduction)
- Spearheaded migration from VMware NSX to Illumio for host-based micro-segmentation and zero-trust security
- Infrastructure security design, vulnerability remediation, and compliance
- Member of Disaster Recovery Team
- Hyper-V
- Azure
- Illumio
- PowerShell
- Cisco
- -
Enterprise Architect @ Healthcare Organization
US - On-siteSummary:
- Enterprise-level IS design, planning, and architecture across on-premise and cloud infrastructures. Supervision of IT team with guidance on task assignment and resource allocation.
Responsibilities:
- Implementation of micro-segmentation with VMware NSX-T
- vCenter and NSX-T Federation between multiple data centers
- Azure AD integration with on-premise Active Directory
- Migration from IBM TSM to Rubrik for disaster recovery
- Automation of security updates and vulnerability remediation via Ansible and Puppet
- VMware
- NSX-T
- Azure
- Ansible
- Rubrik
- -
Technical Team Lead @ Healthcare Organization
US - On-siteSummary:
- Led infrastructure team while performing System Engineer duties. Coordinated projects, schedules, and resource procurement across teams.
Responsibilities:
- Infrastructure team leadership and mentoring
- Project coordination between stakeholders and technical teams
- Resource procurement and implementation of approved designs
- VMware
- Cisco UCS
- Windows Server
- -
Systems Engineer @ Healthcare Organization
US - On-siteSummary:
- Core infrastructure engineer responsible for virtualization, storage, networking, and messaging platform migrations.
Responsibilities:
- VMware vSphere migrations (4.1 → 5.x → 6.0)
- Migration from IBM Blade Center to Cisco UCS
- Exchange migrations (2003 → 2010 → 2016)
- Storage migrations: IBM XIV → V7000 → Pure Storage
- Active Directory upgrades (2003 → 2008 → 2016)
- VMware
- Exchange
- Pure Storage
- Cisco UCS
- -
Lead Systems Engineer @ Insurance Corporation
US - On-siteSummary:
- Led virtualization initiative and data center infrastructure buildout. Complete physical-to-virtual migration.
Responsibilities:
- Implemented and managed VMware infrastructure (4.0 → 5.1)
- Data center hardware: Cisco UCS and EMC VNX
- Complete P2V migration of physical environment
- ESX Clusters, HA, DRS, Distributed Switches design
- Network security: Cisco ASA, site-to-site VPN, AnyConnect
- VMware
- Cisco
- EMC
- Veeam
- -
Network Analyst @ Networking Firm
US - On-siteSummary:
- Network security and remote access solutions design and implementation.
Responsibilities:
- Cisco ASA firewall management and configuration
- Site-to-site IPsec VPN tunnel design
- Remote access solutions: VMware View, Citrix, AnyConnect
- Cisco
- -
Network & Systems Administrator @ Defense Contractor
US - On-siteSummary:
- Built and managed entire Windows and network infrastructure for a defense technology company. Designed secure remote access for military training environments.
Responsibilities:
- Rebuilt entire Windows infrastructure from NT to Windows 2003 AD
- Redesigned network with logical VLANs for security segmentation
- Designed secure remote site access over 3G for military trainers in isolated locations
- Managed Exchange 5.5 → Exchange 2000 migration
- TCP/IP network infrastructure design and maintenance
- Windows Server
- Cisco
- Exchange
Projects
Built a fully autonomous AI assistant running on a Mac Studio that manages infrastructure monitoring, task automation, health tracking, and daily workflows via Telegram, Discord, and web interfaces.
- 🤖 Claude AI with persistent memory and multi-session management
- 📊 Automated infrastructure health checks across 18+ services
- 📅 Intelligent calendar parsing and Workfront timesheet automation
- 🔄 Sub-agent orchestration for parallel task execution
- 📱 Multi-channel: Telegram, Discord, webchat integration
- Node.js
- Claude AI
- Docker
- Cloudflare
Designed and deployed a comprehensive monitoring solution for hybrid infrastructure — tracking Windows servers, Docker containers, network devices, and cloud services with real-time dashboards and alerting.
- 📈 Prometheus + Grafana dashboards for full infrastructure visibility
- 🖥️ Windows Exporter for AD, DNS, Hyper-V metrics
- 🔍 Blackbox Exporter for endpoint availability monitoring
- 🐳 Containerized deployment on Docker host
- 🌐 Cloudflare tunnel for secure external access
- Prometheus
- Grafana
- Docker
- Linux
PowerShell-driven automation for Microsoft System Center Virtual Machine Manager — automated VM provisioning, highly available deployments, and infrastructure reporting across Hyper-V clusters.
- ⚡ Automated HA VM deployment across clustered storage
- 📋 Infrastructure reporting with AD, DNS, and compute metrics
- 🔧 PowerShell modules for SCVMM management
- 🖥️ Remote management via SSH relay from Mac/Linux
- PowerShell
- Windows Server
- Hyper-V
End-to-end health data platform integrating Apple Health data with AI-powered macro estimation, workout tracking, and clinical health monitoring via a dedicated AI assistant.
- 🍎 Apple Health auto-sync via REST API
- 🥗 AI-powered macro estimation using local LLMs (Ollama)
- 💪 Workout logging and exercise tracking
- 🤖 Dedicated Haiku-powered health bot on Telegram
- Node.js
- Docker
- Ollama
- Claude AI
Raspberry Pi-powered robot car with AI vision capabilities — Claude-powered brain for autonomous navigation, obstacle detection, and voice interaction via custom relay server.
- 🎥 Camera with pan-tilt mount for vision analysis
- 🧠 Claude Vision API for scene understanding
- 🔊 Text-to-speech via I2S DAC audio system
- 🕹️ Natural language command interface
- Python
- Raspberry Pi
- Claude AI
- Node.js
Terminal UI dashboard built in Go using Bubbletea — real-time monitoring companion for OpenClaw showing session status, cron jobs, and sub-agent activity with ASCII animations.
- 🖥️ Real-time session and cron job monitoring
- 🤖 ASCII robot animation for active sub-agents
- 📊 Go + Bubbletea + Lipgloss terminal UI
- ⚡ Single 9MB binary, zero dependencies
- Go
- Bubbletea
Led physical data center consolidation for a healthcare organization — reduced footprint by 75% while implementing Azure hybrid cloud for disaster recovery.
- 🏢 Consolidated from 2 data centers to 1
- 📦 Reduced from 8 racks to 2 (75% reduction)
- ☁️ Implemented Azure hybrid cloud for DR
- 💰 Significant cost reduction in power, cooling, and colocation
- Azure
- Hyper-V
- PowerShell
Enterprise-wide virtualization platform migration from VMware vSphere to Microsoft Hyper-V — consolidated 800 VMs to 350 while optimizing resource utilization.
- 🔄 Migrated entire VMware estate to Hyper-V/SCVMM
- 📉 Consolidated 800 VMs to 350 (56% reduction)
- ⚡ Optimized resource utilization across clusters
- 🛡️ Zero unplanned downtime during migration
- VMware
- Hyper-V
- PowerShell
- SCVMM
Migrated enterprise network security from VMware NSX to Illumio for host-based micro-segmentation, enhancing zero-trust posture across the entire infrastructure.
- 🔒 VMware NSX → Illumio migration
- 🛡️ Host-based micro-segmentation across all workloads
- 📊 Real-time application dependency mapping
- ✅ Enhanced zero-trust security posture
- Illumio
- NSX-T
- PowerShell
Designed and implemented VMware NSX-T Federation between multiple data centers for unified network virtualization and consistent security policy enforcement.
- 🌐 NSX-T Federation across multiple data centers
- 🔗 Unified network policy management
- 🛡️ Consistent micro-segmentation across sites
- 📡 Stretched networking for workload mobility
- NSX-T
- vCenter
- Cisco
Built automated security patching and vulnerability remediation across the entire Windows Server fleet using Ansible and Puppet, replacing manual processes.
- 🤖 Automated OS patching across Windows Server fleet
- 🔧 Ansible playbooks for configuration management
- 🛡️ Automated vulnerability remediation across all devices
- 📋 Compliance reporting and audit trail
- Ansible
- PowerShell
- Windows Server
Migrated enterprise backup and disaster recovery from legacy IBM Tivoli Storage Manager to Rubrik, modernizing data protection with instant recovery and cloud-native capabilities.
- 💾 IBM TSM → Rubrik migration
- ⚡ Instant VM recovery capability
- ☁️ Cloud-native backup and archival
- 📉 Reduced RTO from hours to minutes
- Rubrik
- VMware
- Azure
Complete physical-to-virtual migration of an entire data center environment — designed ESX clusters with HA, DRS, and distributed switches on Cisco UCS and EMC storage.
- 🔄 100% physical to virtual conversion
- 🏗️ ESX Clusters with HA, DRS, Distributed Switches
- 🖥️ Cisco UCS compute + EMC VNX storage platform
- 📈 Improved resource utilization and disaster recovery
- VMware
- Cisco UCS
- EMC
Multi-phase enterprise storage migration from IBM legacy platforms to all-flash Pure Storage, dramatically improving IOPS performance and reducing management overhead.
- 💾 IBM XIV → IBM V7000 → Pure Storage migration path
- ⚡ All-flash arrays — massive IOPS improvement
- 📉 Reduced storage management overhead
- 🔄 Non-disruptive data migrations
- Pure Storage
- VMware
- PowerShell
Designed secure remote site access over 3G networks for military training simulators deployed in isolated field locations — enabling real-time data sync and management from HQ.
- 🎖️ Remote access for military trainers in isolated locations
- 📡 Secure connectivity over 3G cellular networks
- 🔒 VPN tunnels with encryption for classified environments
- 🌐 Real-time data sync between field and HQ
- Cisco
- Windows Server
Skills
- PowerShell
- Windows Server
- VMware
- Hyper-V / SCVMM
- Azure
- Cisco
- Docker
- Linux
- Python
- Node.js
- Prometheus
- Grafana
- Cloudflare
- Git
- GitHub
- Terraform
- AI / LLMs
- Omnissa Horizon