Nightscout in your Synology NAS

A valid solution for knowledgeable people, some projects here:

https://t1d.dzienia.pl/nightscout_synology_tutorial/.

https://github.com/vanelsberg/NightScoutSynology

Nightscout on Synology DS220+ - Complete Installation Guide

Successfully Running Nightscout with LibreLink Bridge on Limited Hardware

A community guide based on real-world troubleshooting and successful deployment from Richard v.E.

Table of Contents

Overview
Hardware Limitations & Solutions
Prerequisites
Working Configuration
Installation Script
Common Pitfalls & Solutions
Verification Steps
Maintenance
Synology DSM Configuration

1. Overview

This guide documents a proven working configuration for running Nightscout with LibreLink Bridge on a Synology DS220+ NAS. After extensive troubleshooting, this setup has been running stable with real-time glucose updates every minute.

Key Achievements:

MongoDB running stable on limited hardware
LibreLink Bridge uploading data every minute
No CPU compatibility errors
Minimal resource usage
Automatic recovery on failure

2. Hardware Limitations & Solutions

DS220+ Specific Challenges:

Issue	Solution
No AVX CPU support	Use MongoDB 3.6 (last version without AVX requirement)
No CPU CFS scheduler	Remove all CPU limits from Docker configs
Limited RAM	Use memory limits only, optimize cache sizes
Docker Compose version	Use version 3.3 with `mem_limit` instead of `deploy`

Critical Discovery:

DOES NOT WORK on DS220+

deploy:
  resources:
    limits:
      cpus: '0.5' # Kernel doesn't support this!

WORKS on DS220+

mem_limit: 400m # Only memory limits work

3. Prerequisites

Synology DS220+ with DSM 7.x
Docker & Docker Compose installed via Package Center
Port 1337 available for Nightscout
LibreLink/LibreView account with follower access
Domain name (optional, for HTTPS access)

4. Working Configuration

docker-compose.yml

version: '3.3'

services:
# MongoDB 3.6 - CRITICAL: Don't use newer versions!
  mongodb:
    image: mongo:3.6
    container_name: nightscout-mongodb
    restart: unless-stopped
    environment:
      MONGO_INITDB_ROOT_USERNAME: admin
      MONGO_INITDB_ROOT_PASSWORD: [SECURE_PASSWORD_HERE]
    networks:
      - nightscout-net
    mem_limit: 400m
# Optimized for DS220+ limited resources
    command: mongod --smallfiles --oplogSize 128 --storageEngine wiredTiger --wiredTigerCacheSizeGB 0.25

# Nightscout Application
  nightscout:
    image: nightscout/cgm-remote-monitor:latest
    container_name: nightscout-app
    restart: unless-stopped
    depends_on:
      - mongodb
    environment:

# MongoDB Connection
      MONGODB_URI: mongodb://admin:[MONGO_PASSWORD]@mongodb:27017/nightscout?authSource=admin

# API Configuration - CRITICAL: Save this!
      API_SECRET: [YOUR_API_SECRET_HERE]

# Basic Settings
      NODE_ENV: production
      TZ: Europe/Amsterdam
      DISPLAY_UNITS: mmol # or mgdl

# Minimal plugins for performance
      ENABLE: careportal basal iob cob bwp rawbg direction

# Performance optimization for limited RAM
      NODE_OPTIONS: --max-old-space-size=256

# Required for local network access
      INSECURE_USE_HTTP: "true"

    ports:
      - "1337:1337"
    networks:
      - nightscout-net
    mem_limit: 300m

# LibreLink Bridge

  librelink:
    image: timoschlueter/nightscout-librelink-up:latest
    container_name: nightscout-librelink-up
    restart: unless-stopped
    depends_on:
      - nightscout
    environment:

# LibreView Credentials
      LINK_UP_USERNAME: "[YOUR_LIBREVIEW_EMAIL]"
      LINK_UP_PASSWORD: "[YOUR_LIBREVIEW_PASSWORD]"
      LINK_UP_REGION: "EU" # or US

# CRITICAL: NO http:// prefix!
      NIGHTSCOUT_URL: "nightscout-app:1337"

# CRITICAL: Must be SHA7 hash of APL_SECRET!
      NIGHTSCOUT_API_TOKEN: "[SHA1_HASH_OF_API_SECRET]"

      NIGHTSCOUT_DISABLE_HTTPS: "true"
      LOG_LEVEL: "info"

# Update interval in minutes
      LINK_UP_TIME_INTERVAL: "1"

    networks:
      - nightscout-net
    mem_limit: 128m

  networks:
    nightscout-net:
      driver: bridge

5. Installation Script

Save this as install_nightscout.sh:

#!/bin/bash

# Nightscout DS220+ Installer

# Tested and working configuration

BASE_DIR="/volume1/docker/nightscout"

echo "============================================"
echo "Nightscout DS220+ Installer"
echo "============================================"

# Check root
if [[ $EUID -ne 0 ]]; then
  echo "Please run as root: sudo $0"
  exit 1
fi

# Cleanup old installations

echo "Step 1: Cleaning up old containers..."
docker stop nightscout-app nightscout-mongodb nightscout-librelink-up 2>/dev/null
docker rm -f nightscout-app nightscout-mongodb nightscout-librelink-up 2>/dev/null
docker network rm nightscout-net 2>/dev/null

# Create directory
echo "Step 2: Creating directory structure..."
mkdir -p $BASE_DIR
cd $BASE_DIR

# IMPORTANT. Generate SHA1 hash of your API_SECRET
echo "Step 3: Generating API token hash..."
read -p “Enter your API_SECRET: " API_SECRET
APILHASH=$(echo -n "$API_SECRET" | shalsum | cut -d' ' -f1)
echo "SHA1 hash: $API_HASH"
echo "Save this hash for docker-compose.yml!"

# Create docker-compose.yml
echo "Step 4: Creating docker-compose.ymil..."
echo "Please edit docker-compose.yml and add:"
echo " - Your MongoDB password"
echo " - Your API_SECRET"
echo" - SHA1 hash: $API_HASH"
echo " - Your LibreView credentials"

# Start containers
echo "Step 5: Starting containers..."
docker-compose up -d


echo "Installation complete!"
echo "Wait 2-3 minutes, then test: http://localhost:1337"

6. Common Pitfalls & Solutions

CRITICAL ISSUES THAT WILL BREAK YOUR SETUP:

a) LibreLink URL Format

WRONG: Causes getaddrinfo ENOTFOUND http error.

NIGHTSCOUT_URL: "http://nightscout-app:1337"

CORRECT: No protocol prefix

NIGHTSCOUT_URL: "nightscout-app:1337"

b) API Token Format

yaml

WRONG: Plain text API_SECRET

NIGHTSCOUT_API_TOKEN: "YourApiSecretHere"

CORRECT: SHA1 hash of API_SECRET

NIGHTSCOUT_API_TOKEN: "756a5977a6d0b10d219a81c8b5d923a2fcf97f36"

To generate SHA1 hash:

echo -n "YourApiSecretHere" | shat1sum | cut -d' ' -f1

c) MongoDB Version

WRONG: MongoDB 5.0+ requires AVX support

image: mongo:latest

CORRECT: MongoDB 3.6 works without AVX

image: mongo:3.6

d) Docker Compose CPU Limits

WRONG: Causes NanoCPUs cannot be set error

deploy:
  resources:
    limits:
      cpus: '0.5' # Kernel doesn't support this!

CORRECT: use mem_linit only

mem_limit: 400m # Only memory limits work

7. Verification Steps

a) Check Container Status

docker ps --format "table {{.Names}}\t{{.Status}}"

All three containers should show “Up X minutes”

b) Test Nightscout API

# First get your API_SECRET hash
API_HASH=$(echo -n "YOUR_API_SECRET" | sha1sum | cut -d' ' -f1)

# Test your API
curl -H “api-secret: $API_HASH" http://localhost:1337/api/v1/entries.json

Should return JSON data or empty array []

c) Check LibreLink Logs

docker logs nightscout-librelink-up --tail 10

Look for: Upload of X measurements to Nightscout succeeded

d) Monitor Resource Usage

docker stats --no-stream

Ensure memory usage stays under 80%

8. Maintenance

Daily Backup Script

Save as /volume1/docker/nightscout/backup.sh

#!/bin/bash

BACKUP_DIR="/volume1/docker/nightscout_backups"
DATE=$(date +%Y%m%d)

# Create backup directory
mkdir -p $BACKUP_DIR

# Export MongoDB data
docker exec nightscout-mongodb mongodump \
  --username admin \
  --password [YOUR_MONGO_PASSWORD] \
  --authenticationDatabase admin \
  --archive > $BACKUP_DIR/mongo_$DATE.archive

# Backup docker-compose
cp /volume1/docker/nightscout/docker-compose.yml $BACKUP_DIR/

echo “Backup completed: $BACKUP_DIR"

Useful Commands

Restart all services:

cd /volume1/docker/nightscout && docker-compose restart

View real-time logs:

docker logs -f nightscout-librelink-up

Check Nightscout web interface:

curl http://localhost:1337

Emergency reset:

docker-compose down && docker-compose up -d

8. Synology DSM Configuration

Reverse Proxy Setup (for HTTPS access)

Control Panel -> Application Portal -> Reverse Proxy
Create new rule:

Source: HTTPS, your-domain.com, 443
Destination: HTTP, localhost, 1337

Custom Header -> Create -> WebSocket
Save

SSL Certificate

Control Panel — Security — Certificate
Add — Get from Let’s Encrypt
Enter your domain
Apply

Success Indicators

Your installation is successful when:

All containers show “Up” status
LibreLink logs show “Upload succeeded”
API returns glucose data
Web interface shows real-time glucose values
Memory usage stays stable under 400MB per container

Credits & Notes

This guide is based on extensive real-world troubleshooting on a production DS220+ system. The configuration has been tested and proven stable with:

Continuous uptime of 30+ days
Real-time updates every minute
Automatic recovery from network interruptions
Minimal resource usage

Special Notes:

The DS220+ CPU limitations require specific workarounds MongoDB 3.6 is the last stable version for this hardware
SHA1 hashing of API_SECRET is mandatory for LibreLink Bridge Never include http:// in NIGHTSCOUT_URL

Troubleshooting Checklist

If things don’t work:

ls MongoDB 3.6 (not newer)?
Is NIGHTSCOUT_URL without http://?
Is API_TOKEN a SHA1 hash?
Are all containers on same network?
No CPU limits in docker-compose?
Port 1337 not blocked?

Last updated: September 2025 Tested on: Synology DS220+ with DSM 7.2 Working with: Nightscout 15.x, MongoDB 3.6, LibreLink Bridge 2.8