IT Administrators


1-DRC INSIGHT - Central Office Services (COS) Overview


Audience: IT Administrators / MSP Engineers

Purpose: Explain what COS is, what it does, and how it fits into DRC INSIGHT testing.

Overview

DRC INSIGHT Central Office Services (COS) is a local content hosting system that allows testing devices to retrieve assessment content from a local server instead of relying entirely on internet delivery.

Key Concept:
COS is a service-based HTTP system, not a file share.
Testing devices do not browse or mount /opt/CentralOffice.

How COS Fits into DRC INSIGHT

DRC’s training materials describe COS as the content hosting layer for testing devices. When COS is available, test content is delivered locally. If COS is unavailable, content can fall back to DRC cloud delivery. :contentReference[oaicite:1]{index=1}

Testing Devices
    ↓
DRC INSIGHT Secure App
    ↓
COS Service Device
    ↓
Local Content Delivery
    ↓
Fallback → DRC Cloud

Supported Platforms

DRC states that testing devices can connect to any supported COS operating system type. :contentReference[oaicite:2]{index=2}

Main COS Components

Important Design Notes

Next Page: Ubuntu COS Installation

2-DRC INSIGHT - Ubuntu COS Installation


Purpose: Install the COS Service Device on Ubuntu and verify the core services start correctly.

Prerequisites

Step 1 - Update Ubuntu

sudo apt update && sudo apt upgrade -y

Step 2 - Install Required Dependencies

sudo apt install -y \
libxcb-xinerama0 \
libalt-getopt-complete-perl \
libxcb-icccm4 \
libxcb-image0 \
libxcb-keysyms1 \
libxcb-render-util0 \
libxcb-xkb1 \
libxkbcommon-x11-0
Critical:
If these packages are missing, COS may install incompletely, fail silently, or launch only partial services.

Step 3 - Fix /tmp Permissions

sudo chmod 1777 /tmp
ls -ld /tmp

The COS installer writes temporary lock files to /tmp. Incorrect permissions can break the installer.

Step 4 - Clean a Failed Installation (If Needed)

sudo rm -rf /opt/CentralOffice
sudo rm -f /tmp/coinstaller*.lock

Step 5 - Run the Installer

chmod +x silent-linux.sh
sudo ./silent-linux.sh

DRC recommends using the default install locations. During installation, save the setup URL displayed by the wizard, because it can be used to resume or complete the process. :contentReference[oaicite:3]{index=3}

Step 6 - Verify Installation Files

ls /opt/CentralOffice

Expected folders include:

Step 7 - Verify Running Services

sudo /opt/CentralOffice/node \
/opt/CentralOffice/setup/node_modules/forever/bin/forever -p /opt/CentralOffice list

Expected:

Step 8 - Check Active Ports

sudo ss -tulnp | grep node

DRC training shows COS uses a base port, commonly 55222, and assigns consecutive ports from there. In this deployment, the active ports observed were 55223, 55224, and 55225. :contentReference[oaicite:4]{index=4}

Step 9 - Test Local Response

curl -I http://127.0.0.1:55223
Expected Result:
HTTP 404 on the root path is acceptable. It confirms the service is alive even if the root URL is not the correct application route.

Next Page: DRC Portal Configuration

3-DRC INSIGHT - DRC Portal Configuration for COS

Purpose: Complete registration and configure Content Management and Content Hosting correctly.

Step 1 - Complete COS Registration

Open the setup URL generated during installation and complete the COS registration in the DRC portal.

Important:
If registration is not completed, relay and contenthosting may fail and devices may not be able to connect.

Step 2 - Content Management

DRC states that Content Management is used to choose the testing content and accommodations hosted by the COS Service Device. :contentReference[oaicite:5]{index=5}

Step 3 - Content Hosting

Do Not Use Shared Content for a Single Server:
Shared content is only appropriate in multi-server designs with a real shared storage architecture.

Step 4 - Proxy Settings

For a normal single COS Service Device deployment, avoid unnecessary proxy layers unless your network design specifically requires them.

Step 5 - Add Testing Programs and Sites

Use the Locations section to add the relevant testing programs and school or district site assignments to the COS Configuration. :contentReference[oaicite:6]{index=6}

Step 6 - Save and Validate

DRC advises verifying that the configuration is green before students start testing each day. :contentReference[oaicite:7]{index=7}

Next Page: Chromebook Deployment

4-DRC INSIGHT - Chromebook Deployment SOP


Purpose: Deploy the DRC INSIGHT app to Chromebooks and prepare them for testing with COS.

Step 1 - Install DRC INSIGHT

Deploy the DRC INSIGHT app through Google Admin Console.

DRC states that ChromeOS installations are deployed using Google Admin. :contentReference[oaicite:8]{index=8}

Step 2 - Register Each Chromebook

  1. Launch DRC INSIGHT
  2. Select Assign Device to ORG Unit
  3. Enter the COS ORG Unit ID
  4. Select Register

DRC training identifies ORG Unit assignment as a supported method for registering testing devices to a COS Configuration. :contentReference[oaicite:9]{index=9}

Step 3 - Chromebook Settings Required by DRC

DRC specifically states that ChromeOS display size should be 100%, and the keyboard should be US English so quotation marks and apostrophes display correctly. :contentReference[oaicite:10]{index=10}

Step 4 - Same Network Requirement

Keep Chromebooks on the same network path as the COS server during testing for reliable access to local content.

Step 5 - Run Readiness Checks

Use the DRC INSIGHT readiness and system checks before testing begins. DRC states the System Readiness Check helps confirm that each testing device meets minimum requirements and is operating properly before testing. :contentReference[oaicite:11]{index=11}

Next Page: Validation and Testing

5-DRC INSIGHT - Validation and Testing


Purpose: Confirm COS is functioning properly before live testing begins.

Step 1 - Verify Services

sudo /opt/CentralOffice/node \
/opt/CentralOffice/setup/node_modules/forever/bin/forever -p /opt/CentralOffice list

Confirm all four are running:

Step 2 - Verify Ports

sudo ss -tulnp | grep node

Step 3 - Validate Local HTTP Response

curl -I http://127.0.0.1:55223
curl -I http://127.0.0.1:55224
curl -I http://127.0.0.1:55225

An HTTP 404 response at the root path can still indicate a healthy service.

Step 4 - Validate Content Directory

ls -lah /opt/CentralOffice/content_fs

The local content directory should populate after configuration is updated and content is downloaded.

Step 5 - Confirm DRC Portal Status

Step 6 - Validate Chromebook Access

Pre-Test Validation Checklist

Next Page: Troubleshooting

6-DRC INSIGHT - COS Troubleshooting


Purpose: Resolve the most common Linux COS installation, service, and Chromebook issues.

Issue 1 - Installer Fails or Stops Early

Symptoms:

Fix:

sudo chmod 1777 /tmp
sudo rm -rf /opt/CentralOffice
sudo rm -f /tmp/coinstaller*.lock
sudo ./silent-linux.sh

Issue 2 - Only Proxy Runs

Symptoms:

Likely Cause:

Fix:

Issue 3 - Relay Heartbeat Error

Error:

CO API - Heartbeat returned undefined

Likely Cause:

Fix:

Issue 4 - Services Show "active (exited)"

This can be normal. COS uses forever to launch Node services in the background, so the systemd wrapper may show as exited while the Node processes continue running.

Use this command as the truth source:

sudo /opt/CentralOffice/node \
/opt/CentralOffice/setup/node_modules/forever/bin/forever -p /opt/CentralOffice list

Issue 5 - Chromebooks Cannot Connect

Check:

Issue 6 - Content Does Not Download

Check:

Useful Commands

# Check runtime services
sudo /opt/CentralOffice/node \
/opt/CentralOffice/setup/node_modules/forever/bin/forever -p /opt/CentralOffice list

# Check ports
sudo ss -tulnp | grep node

# Check content directory
ls -lah /opt/CentralOffice/content_fs

# Follow content hosting logs
sudo journalctl -u centralofficecontenthosting -f

# Follow relay logs
sudo journalctl -u centralofficerelay -f

Support Contacts

End of Troubleshooting SOP

DRC INSIGHT – Central Office Services (COS) Installation & Troubleshooting (Full)


Audience: IT Administrators / MSP Engineers

Platform: Ubuntu 22.04 / 24.04 + Chromebook environments

Overview

DRC INSIGHT Central Office Services (COS) is a local content hosting system that allows testing devices to retrieve assessment content from a local server instead of the internet.

Key Concept:
COS is a service-based HTTP system, NOT a file share.
Devices do NOT access /opt/CentralOffice directly.

Architecture

Testing Devices
    ↓
DRC INSIGHT App
    ↓
COS Server
    ↓
Local Content (/opt/CentralOffice/content_fs)
    ↓
Fallback → DRC Cloud

Installation (Ubuntu)

1. Update System

sudo apt update && sudo apt upgrade -y

2. Install Required Dependencies

sudo apt install -y \
libxcb-xinerama0 \
libalt-getopt-complete-perl \
libxcb-icccm4 \
libxcb-image0 \
libxcb-keysyms1 \
libxcb-render-util0 \
libxcb-xkb1 \
libxkbcommon-x11-0
Critical: Missing dependencies will cause silent installer failures or services crashing.

3. Fix /tmp Permissions

sudo chmod 1777 /tmp
ls -ld /tmp

4. Clean Previous Install

sudo rm -rf /opt/CentralOffice
sudo rm -f /tmp/coinstaller*.lock

5. Run Installer

chmod +x silent-linux.sh
sudo ./silent-linux.sh

Registration (REQUIRED)

Important: You MUST open the setup URL generated during installation.

This step registers COS with DRC and enables services.

If skipped:

Validate Services

Check Running Services

sudo /opt/CentralOffice/node \
/opt/CentralOffice/setup/node_modules/forever/bin/forever -p /opt/CentralOffice list

Expected:

Check Ports

sudo ss -tulnp | grep node

Typical Ports:

Test Service

curl -I http://127.0.0.1:55223

HTTP 404 is normal and confirms the service is running.

DRC Portal Configuration

Content Management

Content Hosting

Shared content should only be used in multi-server environments.

Proxy

Chromebook Configuration

Install App

Register Device

Launch App → Assign Device to ORG Unit → Enter ORG ID

Required Settings

Network Requirements

Allowlist

*.drcedirect.com

Ports

Internal COS Ports

sudo ufw allow 55223/tcp
sudo ufw allow 55224/tcp
sudo ufw allow 55225/tcp

Content Validation

ls -lah /opt/CentralOffice/content_fs
sudo journalctl -u centralofficecontenthosting -f

Troubleshooting

Installer Fails

sudo chmod 1777 /tmp
sudo rm -rf /opt/CentralOffice
sudo ./silent-linux.sh

Only Proxy Running

Cause: COS not registered

Heartbeat Error

CO API - Heartbeat returned undefined

Fix:

Chromebooks Cannot Connect

Validation Checklist

Key Takeaways

End of SOP