Hypervisor

A hypervisor is a software or Firmware layer that enables Virtualisation by running multiple virtual machines (VMs) simultaneously on the same physical hardware. Within modern OT and Industrial Automation environments, the hypervisor forms the fundamental basis for Virtualisation, containerised workloads, Edge Computing and software-defined OT platforms.

Hypervisors are deployed within industrial infrastructures for:

• SCADA
• Historian
• MES
• HMI
• Engineering Station
• Soft PLC
• edge gateways
• OT data platforms

By enabling virtualisation, hypervisors support the shift towards modern IT OT Convergence architectures in which OT systems are increasingly integrated with IT infrastructures, cloud platforms and software-based automation.

⚙️ What is a hypervisor

A hypervisor abstracts physical hardware resources so that multiple virtual systems CAN run independently of each other.

The hypervisor manages:

• CPU scheduling
• memory allocation
• storage access
• network virtualisation
• hardware abstraction
• interrupt handling
• device sharing

Architecture:

Virtual Machine
      │
   Guest OS
      │
   Hypervisor
      │
Physical Hardware

Each virtual machine functions as if it were a standalone physical system.

🏗️ Types of hypervisors

Type 1 Hypervisor

A Type 1 hypervisor runs directly on physical hardware.

Also known as:

• bare-metal hypervisor
• native hypervisor

Examples:

• VMware ESXi
• Microsoft Hyper-V
• Xen
• KVM

Architecture:

VM
 │
Hypervisor
 │
Hardware

Benefits:

• high performance
• low overhead
• better isolation
• higher reliability
• suitable for production OT

Within industrial environments, Type 1 hypervisors are dominant.

Type 2 Hypervisor

A Type 2 hypervisor runs on top of a host operating system.

Examples:

• VMware Workstation
• VirtualBox
• Parallels

Architecture:

VM
 │
Hypervisor
 │
Host OS
 │
Hardware

Benefits:

• easy installation
• suitable for labs
• handy for simulation

Drawbacks:

• higher Latency
• additional overhead
• less Deterministic Behaviour

Within OT, Type 2 hypervisors are mainly used for:

• test environments
• engineering
• simulation
• training

🧠 Virtualisation principles

A hypervisor creates virtual hardware for guest systems.

Important virtualisation components:

Hypervisors manage resource sharing between VMs.

⚡ Hypervisors within OT

Within Industrial Automation, hypervisors are used to consolidate OT systems.

Typical OT workloads

🖥️ Hypervisors and SCADA

Modern SCADA environments often run fully virtualised.

Typical architecture:

VM Cluster
 ├── SCADA Server
 ├── Historian
 ├── OPC Server
 ├── Alarm Server
 └── Engineering VM

Benefits:

• hardware consolidation
• easy Recovery
• snapshots
• High Availability
• central Lifecycle Management

📡 Network virtualisation

Hypervisors often contain virtual networks.

Important components:

OT networks can be logically separated within the same physical infrastructure.

Applications:

• DMZ
• engineering zones
• production OT
• management networks
• test environments

⚡ Real-time challenges

Hypervisors introduce additional scheduling layers.

This affects:

• Latency
• Jitter
• interrupt response
• real-time synchronisation

Issues arise especially with:

• Motion Control
• real-time IO
• high-speed Fieldbuses
• Safety systems

Examples:

Some systems therefore remain dependent on dedicated hardware.

🔄 Resource scheduling

The hypervisor allocates resources dynamically.

Important factors:

Poor configuration can lead to:

• SCADA timeouts
• Historian delay
• HMI freezes
• higher Jitter

☁️ Hyperconverged infrastructure

Many modern OT environments use hyperconverged infrastructures.

These combine:

• compute
• storage
• networking
• virtualisation

Examples:

• VMware vSAN
• Nutanix
• Azure Stack HCI

Benefits:

• scalability
• Redundancy
• central orchestration
• easier management

🔒 Cybersecurity risks

The hypervisor is a critical part of OT infrastructure.

Important risks

Because multiple critical OT systems depend on the same hypervisor, a single compromise can have major impact.

🛡️ Hypervisor Hardening

Important measures:

• dedicated management networks
• MFA
• RBAC
• Secure Boot
• encrypted storage
• management VLANs
• Patch Management
• Logging
• Audit trails

Additional OT measures:

• Industrial Firewall
• Network Segmentation
• Security Monitoring
• Application Whitelisting

🔄 High Availability

Hypervisors support extensive HA functionality.

Commonly used functions

Within critical infrastructures, redundant hypervisor clusters are standard.

🧪 Hypervisors in OTAP and simulation

Hypervisors are ideal for:

• OTAP
• FAT/SAT
• simulation
• cyber ranges
• Digital Twin
• training

Benefits:

• fast provisioning
• rollback
• safe isolation
• reproducible environments

OT engineers can simulate full process environments without physical installations.

📦 Storage virtualisation

Hypervisors often virtualise storage as well.

Typical technologies:

• SAN
• NAS
• software-defined storage
• vSAN

Important considerations:

📡 Hypervisors and Edge Computing

Within Edge Computing, lightweight hypervisors are increasingly popular.

Edge nodes run, for example:

• MQTT brokers
• OPC UA gateways
• AI inferencing
• protocol converters
• analytics

Benefits:

• workload isolation
• local processing
• remote management
• fast deployment

⚠️ Operational risks

Single Point of Failure

Consolidation increases impact of failures.

Failure of a single hypervisor host can affect multiple systems:

• SCADA
• historians
• engineering stations
• protocol gateways

The following are therefore necessary:

• redundant clusters
• failover mechanisms
• Backup strategies
• Disaster Recovery

Resource contention

VMs share hardware.

Issues:

• CPU starvation
• memory pressure
• storage bottlenecks
• Network Congestion

Consequences:

• increased Latency
• higher Jitter
• process delay
• unstable communication

🏭 Practical applications

Manufacturing

Hypervisors for:

• virtual SCADA
• MES platforms
• historians
• AI analytics

Energy supply

Applications:

• EMS systems
• substations
• central monitoring
• OT data platforms

Water sector

Use for:

• redundant SCADA
• Telemetry aggregation
• historian clusters

Building Automation

Virtualisation of:

• BMS
• HVAC platforms
• energy management

🛠️ Lifecycle management

Hypervisors simplify OT management.

Benefits:

• template deployment
• central provisioning
• snapshots
• automated backups
• fast recovery

Integration with:

• Configuration Management
• Patch Management
• Disaster Recovery
• Business Continuity

🛡️ Relevant standards and frameworks

For safety-critical workloads, additional validation requirements often apply.

📈 Trends and developments

Important trends:

• software-defined data centres
• edge virtualisation
• container-native hypervisors
• hyperconverged OT
• lightweight hypervisors
• confidential computing
• AI-enabled infrastructure

Hypervisors remain a fundamental building block of modern OT infrastructures.

🎯 Conclusion

Hypervisors form the technical basis of modern virtualised OT environments and enable efficient consolidation, scalability and high availability of industrial workloads.

Within IT OT Convergence, hypervisors support the shift towards software-defined infrastructures, edge computing and cloud-native OT platforms.

At the same time, virtualised OT environments require careful attention to real-time behaviour, resource management, cybersecurity and redundancy in order to safeguard industrial reliability and availability.