3D Printer Fleet Management Architecture

Overview

This document outlines the architecture for managing thousands of distributed 3D printers using Zrok as the proxy solution for Moonraker API access. The design focuses on scalability, reliability, and simplicity of implementation.

System Components

1. Local Environment (Printer Side)

3D Printer running Klipper
Moonraker API (port 7125)
Zrok Agent for secure tunneling

2. Control Layer

Central Control Server
Connection Registry Database
Load Manager
Metrics Tracker

3. Infrastructure

Multiple standalone Zrok Frontends
Geographic distribution for better latency
Independent operation for fault isolation

Printer communication Diagram

flowchart TB
    subgraph "Control Layer"
        CS[Control Server] --> |Manages| DB[(Connection Registry)]
        CS --> |Routes| LM[Load Manager]
        LM --> |Monitors| MT[Metrics Tracker]
    end

    subgraph "Zrok Frontends"
        Z1[Zrok Frontend 1\nRegion A]
        Z2[Zrok Frontend 2\nRegion B]
        Z3[Zrok Frontend N\nRegion X]
    end

    subgraph "Printer Agents"
        P1[Printer 1] --> |Get Frontend URL| CS
        P2[Printer 2] --> |Get Frontend URL| CS
        P3[Printer N] --> |Get Frontend URL| CS
        
        P1 -.-> |Connect to assigned| Z1
        P2 -.-> |Connect to assigned| Z2
        P3 -.-> |Connect to assigned| Z3
    end

System communication Diagram

flowchart TB
    subgraph "Content Platform"
        WEB[Web Frontend] --> |API| AS[Application Server]
        AS --> |Manages| SDB[(STL Database)]
        AS --> |Auth| UDB[(User DB)]        
    end

    AS
    CS

    subgraph "Control Layer"        
        
        CS --> |Manages| DB[(Connection Registry)]
        CS --> |Routes| LM[Load Manager]
        
        %% Print Job Flow
        CS[Control Server] 
        PQ[Print Queue Manager]
        CS -->|"5-Send to Queue"| PQ
    end

    subgraph "Zrok Frontends"
        Z1[Zrok Frontend 1\nRegion A]
        Z2[Zrok Frontend 2\nRegion B]
    end

    subgraph "Printer Side"
        P1[Printer 1] --> |Get Frontend URL| CS
        P1
        Z1
        
        M1[Zrok Agent] <--> A1        
        A1[Moonraker API] --> P1        
        Z1 <-.-> |Forward API Calls| M1
    end

    %% Print Flow
    WEB --> |1-Select STL| USER((User))
    USER -->|2-Choose Printer| WEB
    WEB --> |3-Submit Job| AS
    AS -->|"4-Print Jobs"| CS
    PQ -->|"6-Forward to Printer"| Z1

    style WEB fill:#98FB98
    style AS fill:#FFB6C1
    style CS fill:#DDA0DD
    style Z1 fill:#F0E68C
    style Z2 fill:#F0E68C
    style PQ fill:#ff9999

    %% Add notes
    note1[Content website never\nconnects directly\nto printers]
    note2[Control server manages\nall printer communication]
    note3[Print jobs queued\nand monitored]
    
    note1 -.-> AS
    note2 -.-> CS
    note3 -.-> PQ
	subGraph3
	
	subGraph3
	
	note3
	
	subGraph0 --- n4

Clarified Print Job Flow

flowchart TB
    subgraph "Content Platform"
        WEB[Web Frontend] --> |API| AS[Application Server]
        AS --> |Manages| SDB[(STL Database)]
        AS --> |Auth| UDB[(User DB)]
        AS --> |1. Job Commands| CS[Control Server]
    end

    subgraph "Control Layer"
        CS --> |Manages| DB[(Connection Registry)]
        CS --> |Routes| LM[Load Manager]
        
        %% Print Queue Management
        PQ[Print Queue Manager]
        CS --> |2. Schedule Job| PQ
        PQ --> |3. Status Updates| CS
    end

    subgraph "Zrok Frontends"
        Z1[Zrok Frontend 1\nRegion A]
        Z2[Zrok Frontend 2\nRegion B]
    end

    subgraph "Printer Side"
        P1[Printer 1] 
        M1[Moonraker API] --> P1
        Z1 -.-> |4. Execute Job| M1
    end

    style WEB fill:#98FB98
    style AS fill:#FFB6C1
    style CS fill:#DDA0DD
    style PQ fill:#F0E68C

    %% Add notes
    note1[Job Commands:\n- Start Print\n- Cancel Print\n- Get Status]
    note2[Queue Operations:\n- Schedule Jobs\n- Manage Priority\n- Handle Retries]
    
    note1 -.-> AS
    note2 -.-> PQ

Key Design Decisions

1. Use of Zrok

Chosen for its lightweight and reliable tunneling capabilities
Simple deployment and maintenance
No modifications needed to Moonraker API
Secure by default with TLS

2. Distributed Frontend Approach

Multiple standalone Zrok instances instead of clustering
Each frontend operates independently
Simpler than implementing load balancing at Zrok level
Better fault isolation

3. Smart Routing via Control Server

Central control server manages printer-to-frontend assignments
Assignments based on:
- Geographic proximity
- Current frontend load
- System health metrics
- Network conditions

Implementation Requirements

1. Control Server

RESTful API for printer registration
Frontend health monitoring
Connection tracking
Load balancing algorithm
Metrics collection and analysis

2. Zrok Frontend

Minimum Requirements per Instance:
- 1-2 CPU cores
- 1-2 GB RAM
- 10GB storage
- Standard network connection
Scales to approximately 100-200 printers per instance

3. Printer Agent

Zrok agent installation
Initial registration with control server
Automatic reconnection logic
Health reporting

Security Considerations

All connections secured via TLS
Token-based authentication
Isolated printer connections
Access control at control server level

Scaling Strategy

Start with minimal deployment:
- Single frontend
- Basic control server
- Monitor resource usage
Scale horizontally by:
- Adding Zrok frontends in new regions
- Enhancing control server logic
- Implementing more sophisticated routing
Monitor and optimize:
- Track connection metrics
- Analyze geographic distribution
- Adjust routing algorithms

Next Steps

Implementation Priority:
- Set up control server infrastructure
- Deploy first Zrok frontend
- Develop printer registration process
- Implement basic routing logic
Testing:
- Connection reliability
- Failover scenarios
- Load testing
- Geographic distribution effectiveness

vantt/3dprinter