Horizontal Scaling with Redis

Open WebUI supports horizontal scaling with Redis for multi-worker and multi-node deployments behind load balancers. This enables high-availability, fault-tolerant production deployments.

Overview

Redis provides:

Distributed Sessions - Share user sessions across multiple instances
WebSocket State - Synchronized real-time connections across workers
Configuration Sync - Propagate runtime config changes to all nodes
Task Coordination - Distributed task management and pub/sub
Rate Limiting - Centralized rate limit tracking
Token Revocation - Shared JWT token blacklist

Prerequisites

Redis server (standalone, cluster, or Sentinel)
Load balancer (nginx, HAProxy, AWS ALB, etc.)
Multiple Open WebUI instances

Redis Configuration

Standalone Redis

Basic Redis connection:

# Redis connection URL
REDIS_URL=redis://redis-server:6379

# Optional: Redis key prefix (for multi-tenant deployments)
REDIS_KEY_PREFIX=open-webui

# Optional: Socket connection timeout (milliseconds)
REDIS_SOCKET_CONNECT_TIMEOUT=5000

# Optional: Reconnect delay after connection failure (milliseconds)
REDIS_RECONNECT_DELAY=1000

Redis with Authentication

REDIS_URL=redis://:password@redis-server:6379
# Or with username (Redis 6+)
REDIS_URL=redis://username:password@redis-server:6379

Redis with TLS/SSL

REDIS_URL=rediss://redis-server:6380  # Note: rediss:// for TLS

Redis Cluster

For Redis Cluster deployments:

REDIS_URL=redis://node1:6379,node2:6379,node3:6379
REDIS_CLUSTER=true

Redis Sentinel

For high-availability Redis Sentinel:

# Comma-separated Sentinel hosts
REDIS_SENTINEL_HOSTS=sentinel1:26379,sentinel2:26379,sentinel3:26379
REDIS_SENTINEL_PORT=26379

# Master name configured in Sentinel
REDIS_URL=redis://mymaster

# Sentinel retry configuration
REDIS_SENTINEL_MAX_RETRY_COUNT=3
REDIS_RECONNECT_DELAY=1000

Session Management

Redis-backed sessions enable stateless application servers:

# Enable session middleware (required for multi-instance)
ENABLE_STAR_SESSIONS_MIDDLEWARE=true

# Redis URL for session storage
REDIS_URL=redis://redis-server:6379

Session Configuration

# Session cookie settings
WEBUI_SESSION_COOKIE_SAME_SITE=lax  # or 'strict', 'none'
WEBUI_SESSION_COOKIE_SECURE=true  # Require HTTPS

# JWT expiration
JWT_EXPIRES_IN=4w  # 4 weeks, or '7d', '24h', '-1' for never

WebSocket Scaling

Redis enables WebSocket connections across multiple instances:

Real-time chat updates synchronized
Task status notifications broadcast
Multi-node pub/sub messaging

Automatic - WebSocket support is automatically enabled when REDIS_URL is configured.

Persistent Configuration

Enable runtime configuration updates across all instances:

# Enable persistent config with Redis sync
ENABLE_PERSISTENT_CONFIG=true
REDIS_URL=redis://redis-server:6379
REDIS_KEY_PREFIX=open-webui

Configuration changes via Admin UI are:

Saved to database
Published to Redis
Applied to all running instances

Docker Compose Example

Multi-Instance Deployment with Redis

version: '3'

services:
  # Redis for session and state management
  redis:
    image: redis:7-alpine
    command: redis-server --requirepass ${REDIS_PASSWORD}
    volumes:
      - redis-data:/data
    restart: always
    healthcheck:
      test: ["CMD", "redis-cli", "--raw", "incr", "ping"]
      interval: 10s
      timeout: 3s
      retries: 5

  # PostgreSQL database
  postgres:
    image: postgres:16-alpine
    environment:
      POSTGRES_DB: openwebui
      POSTGRES_USER: openwebui
      POSTGRES_PASSWORD: ${POSTGRES_PASSWORD}
    volumes:
      - postgres-data:/var/lib/postgresql/data
    restart: always

  # Open WebUI instance 1
  open-webui-1:
    image: ghcr.io/open-webui/open-webui:main
    environment:
      # Database
      - DATABASE_URL=postgresql://openwebui:${POSTGRES_PASSWORD}@postgres:5432/openwebui
      
      # Redis Configuration
      - REDIS_URL=redis://:${REDIS_PASSWORD}@redis:6379
      - REDIS_KEY_PREFIX=open-webui
      - ENABLE_STAR_SESSIONS_MIDDLEWARE=true
      - ENABLE_PERSISTENT_CONFIG=true
      
      # Instance identification
      - INSTANCE_ID=instance-1
    volumes:
      - open-webui-data:/app/backend/data
    depends_on:
      - redis
      - postgres
    restart: always

  # Open WebUI instance 2
  open-webui-2:
    image: ghcr.io/open-webui/open-webui:main
    environment:
      - DATABASE_URL=postgresql://openwebui:${POSTGRES_PASSWORD}@postgres:5432/openwebui
      - REDIS_URL=redis://:${REDIS_PASSWORD}@redis:6379
      - REDIS_KEY_PREFIX=open-webui
      - ENABLE_STAR_SESSIONS_MIDDLEWARE=true
      - ENABLE_PERSISTENT_CONFIG=true
      - INSTANCE_ID=instance-2
    volumes:
      - open-webui-data:/app/backend/data
    depends_on:
      - redis
      - postgres
    restart: always

  # Open WebUI instance 3
  open-webui-3:
    image: ghcr.io/open-webui/open-webui:main
    environment:
      - DATABASE_URL=postgresql://openwebui:${POSTGRES_PASSWORD}@postgres:5432/openwebui
      - REDIS_URL=redis://:${REDIS_PASSWORD}@redis:6379
      - REDIS_KEY_PREFIX=open-webui
      - ENABLE_STAR_SESSIONS_MIDDLEWARE=true
      - ENABLE_PERSISTENT_CONFIG=true
      - INSTANCE_ID=instance-3
    volumes:
      - open-webui-data:/app/backend/data
    depends_on:
      - redis
      - postgres
    restart: always

  # Nginx load balancer
  nginx:
    image: nginx:alpine
    ports:
      - "80:80"
      - "443:443"
    volumes:
      - ./nginx.conf:/etc/nginx/nginx.conf:ro
      - ./ssl:/etc/nginx/ssl:ro
    depends_on:
      - open-webui-1
      - open-webui-2
      - open-webui-3
    restart: always

volumes:
  redis-data:
  postgres-data:
  open-webui-data:

Nginx Load Balancer Configuration

nginx.conf:

upstream open_webui_backend {
    least_conn;  # Use least connections algorithm
    
    server open-webui-1:8080 max_fails=3 fail_timeout=30s;
    server open-webui-2:8080 max_fails=3 fail_timeout=30s;
    server open-webui-3:8080 max_fails=3 fail_timeout=30s;
}

server {
    listen 80;
    server_name openwebui.company.com;
    
    # Redirect HTTP to HTTPS
    return 301 https://$server_name$request_uri;
}

server {
    listen 443 ssl http2;
    server_name openwebui.company.com;
    
    # SSL Configuration
    ssl_certificate /etc/nginx/ssl/cert.pem;
    ssl_certificate_key /etc/nginx/ssl/key.pem;
    ssl_protocols TLSv1.2 TLSv1.3;
    ssl_ciphers HIGH:!aNULL:!MD5;
    
    # Client upload size
    client_max_body_size 100M;
    
    # WebSocket support
    proxy_http_version 1.1;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection "upgrade";
    
    # Proxy headers
    proxy_set_header Host $host;
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header X-Forwarded-Proto $scheme;
    
    # Timeouts
    proxy_connect_timeout 60s;
    proxy_send_timeout 60s;
    proxy_read_timeout 60s;
    
    location / {
        proxy_pass http://open_webui_backend;
        
        # WebSocket keepalive
        proxy_set_header Connection "upgrade";
        proxy_set_header Upgrade $http_upgrade;
        
        # Disable buffering for streaming responses
        proxy_buffering off;
    }
}

Cloud Deployments

AWS with Application Load Balancer

# Environment variables for ECS/EKS
DATABASE_URL=postgresql://user:pass@rds-endpoint:5432/openwebui
REDIS_URL=redis://elasticache-endpoint:6379
ENABLE_STAR_SESSIONS_MIDDLEWARE=true
ENABLE_PERSISTENT_CONFIG=true

# ALB handles SSL termination
WEBUI_SESSION_COOKIE_SECURE=true

ALB Configuration:

Target Group: Multiple Open WebUI instances
Health Check: /health endpoint
Stickiness: Not required (Redis sessions)
WebSocket: Enable WebSocket upgrade headers

Kubernetes with Ingress

apiVersion: apps/v1
kind: Deployment
metadata:
  name: open-webui
spec:
  replicas: 3
  selector:
    matchLabels:
      app: open-webui
  template:
    metadata:
      labels:
        app: open-webui
    spec:
      containers:
      - name: open-webui
        image: ghcr.io/open-webui/open-webui:main
        env:
        - name: DATABASE_URL
          valueFrom:
            secretKeyRef:
              name: db-credentials
              key: url
        - name: REDIS_URL
          value: "redis://redis-service:6379"
        - name: ENABLE_STAR_SESSIONS_MIDDLEWARE
          value: "true"
        - name: ENABLE_PERSISTENT_CONFIG
          value: "true"
        ports:
        - containerPort: 8080
        volumeMounts:
        - name: data
          mountPath: /app/backend/data
      volumes:
      - name: data
        persistentVolumeClaim:
          claimName: open-webui-data
---
apiVersion: v1
kind: Service
metadata:
  name: open-webui
spec:
  selector:
    app: open-webui
  ports:
  - port: 8080
    targetPort: 8080
  type: ClusterIP
---
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: open-webui
  annotations:
    nginx.ingress.kubernetes.io/websocket-services: open-webui
    nginx.ingress.kubernetes.io/proxy-read-timeout: "3600"
    nginx.ingress.kubernetes.io/proxy-send-timeout: "3600"
spec:
  ingressClassName: nginx
  tls:
  - hosts:
    - openwebui.company.com
    secretName: tls-secret
  rules:
  - host: openwebui.company.com
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: open-webui
            port:
              number: 8080

Redis High Availability

Redis Sentinel

For production deployments with automatic failover:

version: '3'

services:
  redis-master:
    image: redis:7-alpine
    command: redis-server --requirepass ${REDIS_PASSWORD}
    volumes:
      - redis-master:/data

  redis-replica-1:
    image: redis:7-alpine
    command: redis-server --replicaof redis-master 6379 --requirepass ${REDIS_PASSWORD} --masterauth ${REDIS_PASSWORD}
    volumes:
      - redis-replica-1:/data
    depends_on:
      - redis-master

  redis-replica-2:
    image: redis:7-alpine
    command: redis-server --replicaof redis-master 6379 --requirepass ${REDIS_PASSWORD} --masterauth ${REDIS_PASSWORD}
    volumes:
      - redis-replica-2:/data
    depends_on:
      - redis-master

  sentinel-1:
    image: redis:7-alpine
    command: redis-sentinel /etc/redis/sentinel.conf
    volumes:
      - ./sentinel.conf:/etc/redis/sentinel.conf
    depends_on:
      - redis-master

  sentinel-2:
    image: redis:7-alpine
    command: redis-sentinel /etc/redis/sentinel.conf
    volumes:
      - ./sentinel.conf:/etc/redis/sentinel.conf
    depends_on:
      - redis-master

  sentinel-3:
    image: redis:7-alpine
    command: redis-sentinel /etc/redis/sentinel.conf
    volumes:
      - ./sentinel.conf:/etc/redis/sentinel.conf
    depends_on:
      - redis-master

  open-webui:
    image: ghcr.io/open-webui/open-webui:main
    environment:
      - REDIS_URL=redis://mymaster
      - REDIS_SENTINEL_HOSTS=sentinel-1:26379,sentinel-2:26379,sentinel-3:26379
      - REDIS_SENTINEL_PORT=26379
      - REDIS_SENTINEL_MAX_RETRY_COUNT=3
      - ENABLE_STAR_SESSIONS_MIDDLEWARE=true

volumes:
  redis-master:
  redis-replica-1:
  redis-replica-2:

sentinel.conf:

port 26379
sentinel monitor mymaster redis-master 6379 2
sentinel auth-pass mymaster ${REDIS_PASSWORD}
sentinel down-after-milliseconds mymaster 5000
sentinel parallel-syncs mymaster 1
sentinel failover-timeout mymaster 10000

Monitoring and Health Checks

Health Check Endpoint

curl http://localhost:8080/health

Returns:

{
  "status": "ok",
  "version": "0.3.0"
}

Redis Connection Check

# Test Redis connectivity
redis-cli -h redis-server -p 6379 -a password PING
# Should return: PONG

Monitor Redis Keys

# View session keys
redis-cli -h redis-server -p 6379 -a password KEYS "open-webui:*"

# Monitor real-time commands
redis-cli -h redis-server -p 6379 -a password MONITOR

Troubleshooting

Redis Connection Failures

Problem: Cannot connect to Redis Check:

# Test Redis connectivity
telnet redis-server 6379

# Check Redis logs
docker logs redis-container

# Verify credentials
redis-cli -h redis-server -p 6379 -a password PING

Session Loss

Problem: Users logged out frequently Check:

Redis is running and accessible
ENABLE_STAR_SESSIONS_MIDDLEWARE=true is set
REDIS_URL is correctly configured
Redis has sufficient memory (check INFO memory)

WebSocket Disconnections

Problem: Real-time features not working Check:

Load balancer supports WebSocket upgrades
Nginx: proxy_set_header Upgrade $http_upgrade;
ALB: Enable WebSocket support
Redis pub/sub is functioning

Configuration Not Syncing

Problem: Config changes not applied to all instances Check:

ENABLE_PERSISTENT_CONFIG=true on all instances
All instances use same REDIS_URL
Redis pub/sub channels working: redis-cli PUBSUB CHANNELS

Performance Tuning

Redis Optimization

# Increase max connections
maxclients 10000

# Enable persistence for session durability
save 900 1
save 300 10
save 60 10000

# Memory policy
maxmemory 2gb
maxmemory-policy allkeys-lru

Connection Pooling

Open WebUI automatically manages Redis connection pools. Adjust if needed:

# Socket timeout (milliseconds)
REDIS_SOCKET_CONNECT_TIMEOUT=5000

# Reconnect delay after failure (milliseconds)
REDIS_RECONNECT_DELAY=1000

Implementation Details

Redis utilities: backend/open_webui/utils/redis.py
Session management: starsessions[redis]==2.2.1
Task coordination: backend/open_webui/tasks.py
Configuration sync: backend/open_webui/config.py:228-287
Rate limiting: backend/open_webui/utils/rate_limit.py

Security Best Practices

Redis Security:

Authentication - Always use requirepass or ACLs
TLS/SSL - Use rediss:// for encrypted connections
Network Isolation - Bind Redis to private network only
Firewall Rules - Restrict Redis port (6379) access
Regular Updates - Keep Redis updated for security patches
Memory Limits - Set maxmemory to prevent OOM

Next Steps

Observability - Monitor with OpenTelemetry
RBAC - Configure access control
Enterprise Overview - Full enterprise features

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Help

Documentation Index

​Overview

​Prerequisites

​Redis Configuration

​Standalone Redis

​Redis with Authentication

​Redis with TLS/SSL

​Redis Cluster

​Redis Sentinel

​Session Management

​Session Configuration

​WebSocket Scaling

​Persistent Configuration

​Docker Compose Example

​Multi-Instance Deployment with Redis

​Nginx Load Balancer Configuration

​Cloud Deployments

​AWS with Application Load Balancer

​Kubernetes with Ingress

​Redis High Availability

​Redis Sentinel

​Monitoring and Health Checks

​Health Check Endpoint

​Redis Connection Check

​Monitor Redis Keys

​Troubleshooting

​Redis Connection Failures

​Session Loss

​WebSocket Disconnections

​Configuration Not Syncing

​Performance Tuning

​Redis Optimization

​Connection Pooling

​Implementation Details

​Security Best Practices

​Next Steps

Build docs developers (and LLMs) love

Overview

Prerequisites

Redis Configuration

Standalone Redis

Redis with Authentication

Redis with TLS/SSL

Redis Cluster

Redis Sentinel

Session Management

Session Configuration

WebSocket Scaling

Persistent Configuration

Docker Compose Example

Multi-Instance Deployment with Redis

Nginx Load Balancer Configuration

Cloud Deployments

AWS with Application Load Balancer

Kubernetes with Ingress

Redis High Availability

Redis Sentinel

Monitoring and Health Checks

Health Check Endpoint

Redis Connection Check

Monitor Redis Keys

Troubleshooting

Redis Connection Failures

Session Loss

WebSocket Disconnections

Configuration Not Syncing

Performance Tuning

Redis Optimization

Connection Pooling

Implementation Details

Security Best Practices

Next Steps