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: 

 

 Relay fails 

 Contenthosting fails 

 Devices cannot connect 

 

 

 Validate Services 

 Check Running Services 

 sudo /opt/CentralOffice/node \

/opt/CentralOffice/setup/node_modules/forever/bin/forever -p /opt/CentralOffice list 

 Expected: 

 

 management 

 relay 

 proxy 

 contenthosting 

 

 Check Ports 

 sudo ss -tulnp | grep node 

 Typical Ports: 

 

 55223 – Content Hosting 

 55224 – Relay 

 55225 – Proxy 

 

 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 

 

 Enable Content Management → ON 

 Select tests (PSSA, Keystone, CDT) 

 Click Update Configuration 

 

 Content Hosting 

 

 Enable Content Hosting → ON 

 Load Balancer → OFF 

 Shared Content Location → OFF 

 

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

 Proxy 

 

 Use Proxy → OFF 

 

 

 Chromebook Configuration 

 Install App 

 

 Deploy DRC INSIGHT via Google Admin Console 

 

 Register Device 

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

 Required Settings 

 

 Display Scale = 100% 

 Keyboard = US English 

 Same network as COS 

 

 

 Network Requirements 

 Allowlist 

 *.drcedirect.com 

 Ports 

 

 80 (HTTP) 

 443 (HTTPS) 

 

 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: 

 

 Complete setup URL 

 Verify internet access 

 Allow DRC domains 

 

 Chromebooks Cannot Connect 

 

 Verify ORG ID 

 Check network 

 Confirm ports open 

 

 

 Validation Checklist 

 

 [ ] COS services running 

 [ ] Ports listening 

 [ ] Content downloading 

 [ ] Portal configured correctly 

 [ ] Chromebooks registered 

 

 

 Key Takeaways 

 

 COS is NOT a file server 

 Uses HTTP endpoints 

 Registration is required 

 Content hosting must be enabled 

 

 

 End of SOP