Architecture

OpenDT follows a modular architecture designed for datacenter digital twins. This page explains the high-level and detailed design.

High-Level Design

The architecture consists of five main components:

Physical Infrastructure (P)

The Datacenter Twin represents the real physical infrastructure being monitored. In OpenDT, this is simulated by the dc-mock service, which replays historical workload and power data.

Front-end (B)

The Interfaces component provides user access to the system. OpenDT implements this through:

• Grafana Dashboard - Real-time visualization of power consumption and carbon emissions
• REST API - Programmatic access for querying data and controlling topology

Orchestration (C)

The Orchestrator coordinates the flow of data between components. In OpenDT, Kafka serves as the message broker that enables this orchestration, with topics for workload, power, topology, and results.

Data Platform (D, E)

• Telemetry (D) - Power consumption data from the physical infrastructure
• Data Management (E) - Storage and aggregation of simulation results in Parquet files

Simulator (F, G, H, I)

The simulation engine is the core of OpenDT:

• Input (F) - Tasks and topology configuration consumed from Kafka
• Simulation Engine (G) - OpenDC-based power prediction
• Output (H) - Aggregated results written to agg_results.parquet
• Topology Adjuster (I) - The calibrator service that optimizes topology parameters

Virtual Infrastructure (V)

The Digital Twin maintains the virtual representation of the datacenter, including the current topology and calibrated parameters.

Detailed Design

The detailed architecture expands on each component:

Users

OpenDT supports multiple user types:

• Students - Learning about datacenter simulation
• Researchers - Conducting experiments and validating models
• Practitioners - Operating and optimizing real datacenters

Frontend Components

Component	OpenDT Implementation
Web Interface (D)	Grafana Dashboard
Command Line Interface (E)	make commands, CLI scripts
API Server (F)	FastAPI-based REST API

Orchestration Layer

Component	OpenDT Implementation
Physical Orchestrator (B)	dc-mock service
Central Orchestrator (A)	Kafka message broker
Digital Orchestrator (C)	simulator + calibrator services

Data Platform

Component	OpenDT Implementation
Observable Telemetry (K)	dc.power Kafka topic
Non-Observable Telemetry (L)	Derived metrics from simulation
Datalake (M)	Parquet files in data/ directory
Physical & Digital Twin Metadata (N)	topology.json, config.yaml
Twinning Log (O)	agg_results.parquet with timestamps

Simulator Components

Component	OpenDT Implementation
Input (G)	Task accumulator, window manager
Simulation Engine (H)	OpenDC binary invocation
Output (I)	Result processor, Parquet writer
Topology Adjuster (J)	Calibration engine with grid search

Infrastructure State

Physical Infrastructure (P1-P6):

State	Description
System State (P1)	Current datacenter operational status
SLOs (P2)	Service level objectives
Configuration (P3)	Hardware configuration
Workload (P4)	Running tasks and jobs
Software Stack (P5)	Installed software
Topology (P6)	Physical hardware layout

Virtual Infrastructure (V1-V6):

The digital twin mirrors this state, with the ability to modify parameters for what-if analysis:

State	Description
System State (V1)	Simulated operational status
SLOs (V2)	Target service levels
Configuration (V3)	Simulated configuration
Workload (V4)	Replayed workload
Software Stack (V5)	Simulated software
Topology (V6)	Adjustable topology with calibrated parameters

Data Flow

                      Physical Infrastructure
                               │
                               ▼
                          ┌─────────┐
                          │ dc-mock │ (placeholder for real datacenter)
                          └────┬────┘
                               │
              ┌────────────────┼────────────────┐
              ▼                ▼                ▼
         dc.workload      dc.power        dc.topology
              │                │                │
              └────────────────┼────────────────┘
                               │
              ┌────────────────┴────────────────┐
              │                                 │
              ▼                                 ▼
      ┌─────────────┐                   ┌─────────────┐
      │  simulator  │◄── sim.topology ──│ calibrator  │
      └──────┬──────┘         ▲         └─────────────┘
             │                │
             │          ┌─────┴─────┐≈
             │          │    api    │ (can also write topology)
             │          └───────────┘
             │
             ▼              ┌───────────┐     ┌───────────┐
    agg_results.parquet ──► │    api    │ ──► │  Grafana  │
                            └───────────┘     └───────────┘

Service Mapping

Architecture Component	OpenDT Service	Docker Container
Physical Orchestrator	dc-mock	dc-mock
Central Orchestrator	Kafka	kafka
Simulation Engine	simulator	simulator
Topology Adjuster	calibrator	calibrator
API Server	api	api
Web Interface	Grafana	grafana