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Nginx Load Balancing

Настройка балансировки нагрузки с Nginx для высоконагруженных приложений.

Типы балансировки​

Round Robin (по умолчанию)​

# /etc/nginx/conf.d/load-balancer.conf

upstream backend {
    server 192.168.1.10:8080;
    server 192.168.1.11:8080;
    server 192.168.1.12:8080;
}

server {
    listen 80;
    server_name example.com;

    location / {
        proxy_pass http://backend;
        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;
    }
}

Weighted Round Robin​

upstream backend {
    server 192.168.1.10:8080 weight=3;  # Получает 3/6 запросов
    server 192.168.1.11:8080 weight=2;  # Получает 2/6 запросов
    server 192.168.1.12:8080 weight=1;  # Получает 1/6 запросов
}

Least Connections​

upstream backend {
    least_conn;
    server 192.168.1.10:8080;
    server 192.168.1.11:8080;
    server 192.168.1.12:8080;
}

IP Hash (sticky sessions)​

upstream backend {
    ip_hash;
    server 192.168.1.10:8080;
    server 192.168.1.11:8080;
    server 192.168.1.12:8080;
}

Продвинутые настройки upstream​

Конфигурация с параметрами сервера​

upstream backend {
    server 192.168.1.10:8080 weight=3 max_fails=3 fail_timeout=30s;
    server 192.168.1.11:8080 weight=2 max_fails=3 fail_timeout=30s;
    server 192.168.1.12:8080 weight=1 max_fails=3 fail_timeout=30s backup;
    server 192.168.1.13:8080 down;  # Временно отключен
}

server {
    listen 80;
    server_name api.example.com;

    location / {
        proxy_pass http://backend;

        # Настройки прокси
        proxy_connect_timeout 30s;
        proxy_send_timeout 30s;
        proxy_read_timeout 30s;

        # Буферизация
        proxy_buffering on;
        proxy_buffer_size 4k;
        proxy_buffers 8 4k;

        # Заголовки
        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;

        # Обработка ошибок
        proxy_next_upstream error timeout invalid_header http_500 http_502 http_503;
    }
}

Health Check​

upstream backend {
    server 192.168.1.10:8080 max_fails=2 fail_timeout=10s;
    server 192.168.1.11:8080 max_fails=2 fail_timeout=10s;
    server 192.168.1.12:8080 max_fails=2 fail_timeout=10s;
}

server {
    listen 80;
    server_name example.com;

    location /health {
        access_log off;
        return 200 "healthy\n";
        add_header Content-Type text/plain;
    }

    location / {
        proxy_pass http://backend;

        # Health check
        proxy_next_upstream error timeout http_502 http_503 http_504;
        proxy_next_upstream_tries 3;
        proxy_next_upstream_timeout 10s;
    }
}

SSL Load Balancing​

HTTPS балансировка​

upstream backend_ssl {
    server 192.168.1.10:8443;
    server 192.168.1.11:8443;
    server 192.168.1.12:8443;
}

server {
    listen 443 ssl http2;
    server_name secure.example.com;

    ssl_certificate /etc/letsencrypt/live/secure.example.com/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/secure.example.com/privkey.pem;

    ssl_protocols TLSv1.2 TLSv1.3;
    ssl_ciphers ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256;
    ssl_prefer_server_ciphers off;

    location / {
        proxy_pass https://backend_ssl;

        # SSL настройки для upstream
        proxy_ssl_verify off;
        proxy_ssl_session_reuse on;

        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 https;
    }
}

SSL Termination​

upstream backend_http {
    server 192.168.1.10:8080;
    server 192.168.1.11:8080;
    server 192.168.1.12:8080;
}

server {
    listen 443 ssl http2;
    server_name app.example.com;

    ssl_certificate /etc/letsencrypt/live/app.example.com/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/app.example.com/privkey.pem;

    location / {
        proxy_pass http://backend_http;  # HTTP к backend серверам

        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 https;
        proxy_set_header X-Forwarded-Port 443;
    }
}

# Редирект HTTP на HTTPS
server {
    listen 80;
    server_name app.example.com;
    return 301 https://$server_name$request_uri;
}

Балансировка по типу контента​

Разделение статики и API​

upstream api_backend {
    server 192.168.1.10:8080;
    server 192.168.1.11:8080;
}

upstream static_backend {
    server 192.168.1.20:80;
    server 192.168.1.21:80;
}

server {
    listen 80;
    server_name myapp.example.com;

    # API запросы
    location /api/ {
        proxy_pass http://api_backend;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    }

    # Статические файлы
    location ~* \.(css|js|png|jpg|jpeg|gif|ico|svg|woff|woff2|ttf|eot)$ {
        proxy_pass http://static_backend;
        expires 1y;
        add_header Cache-Control "public, immutable";
    }

    # Основное приложение
    location / {
        proxy_pass http://api_backend;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    }
}

Маршрутизация по поддоменам​

upstream app1_backend {
    server 192.168.1.10:8080;
    server 192.168.1.11:8080;
}

upstream app2_backend {
    server 192.168.1.20:8080;
    server 192.168.1.21:8080;
}

# Приложение 1
server {
    listen 80;
    server_name app1.example.com;

    location / {
        proxy_pass http://app1_backend;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    }
}

# Приложение 2
server {
    listen 80;
    server_name app2.example.com;

    location / {
        proxy_pass http://app2_backend;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    }
}

WebSocket балансировка​

Настройка для WebSocket​

upstream websocket_backend {
    server 192.168.1.10:8080;
    server 192.168.1.11:8080;
}

map $http_upgrade $connection_upgrade {
    default upgrade;
    '' close;
}

server {
    listen 80;
    server_name ws.example.com;

    location /ws {
        proxy_pass http://websocket_backend;

        # WebSocket заголовки
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection $connection_upgrade;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;

        # Увеличенные таймауты для WebSocket
        proxy_connect_timeout 60s;
        proxy_send_timeout 60s;
        proxy_read_timeout 60s;
    }
}

Мониторинг и логирование​

Кастомный формат логов​

log_format load_balancer '$remote_addr - $remote_user [$time_local] '
                        '"$request" $status $body_bytes_sent '
                        '"$http_referer" "$http_user_agent" '
                        'upstream_addr=$upstream_addr '
                        'upstream_status=$upstream_status '
                        'upstream_response_time=$upstream_response_time '
                        'request_time=$request_time';

server {
    listen 80;
    server_name example.com;

    access_log /var/log/nginx/load_balancer.log load_balancer;

    location / {
        proxy_pass http://backend;
        # ... остальные настройки
    }
}

Статус страница для мониторинга​

server {
    listen 8080;
    server_name localhost;

    location /nginx_status {
        stub_status on;
        access_log off;
        allow 127.0.0.1;
        allow 192.168.1.0/24;
        deny all;
    }

    location /upstream_status {
        # Требует модуль nginx-module-upstream
        upstream_show;
        access_log off;
        allow 127.0.0.1;
        allow 192.168.1.0/24;
        deny all;
    }
}

Отказоустойчивость​

Конфигурация с backup серверами​

upstream backend {
    server 192.168.1.10:8080 max_fails=3 fail_timeout=30s;
    server 192.168.1.11:8080 max_fails=3 fail_timeout=30s;
    server 192.168.1.12:8080 backup;  # Резервный сервер
    server 192.168.1.13:8080 backup;  # Еще один резервный
}

server {
    listen 80;
    server_name example.com;

    location / {
        proxy_pass http://backend;

        # Retry механизм
        proxy_next_upstream error timeout http_502 http_503 http_504;
        proxy_next_upstream_tries 3;
        proxy_next_upstream_timeout 30s;

        # Кэширование при ошибках
        proxy_cache_use_stale error timeout updating http_500 http_502 http_503 http_504;
    }
}

Graceful shutdown​

#!/bin/bash
# graceful-shutdown.sh

SERVER_IP="192.168.1.10"
NGINX_CONFIG="/etc/nginx/conf.d/load-balancer.conf"

# Пометить сервер как down
sed -i "s/server $SERVER_IP:8080;/server $SERVER_IP:8080 down;/" $NGINX_CONFIG

# Перезагрузить конфигурацию
nginx -s reload

echo "Сервер $SERVER_IP помечен как down"
echo "Ожидание завершения активных соединений..."
sleep 30

# Здесь можно добавить остановку приложения на сервере
Производительность

Используйте keepalive соединения между Nginx и upstream серверами для уменьшения латентности.

Мониторинг

Обязательно настройте мониторинг состояния upstream серверов и автоматические уведомления при отказах.