# 檢查服務是否運行
systemctl status php-fpm  # 以PHP-FPM為例
 
# 嘗試直接訪問上游服務
curl http://127.0.0.1:9000  # PHP-FPM默認端口

# 關鍵配置檢查示例
upstream backend {
    server 192.168.1.100:8080;  # 確認IP和端口是否正確
}
 
server {
    location / {
        proxy_pass http://backend;  # 確認協(xié)議和路徑
        proxy_set_header Host $host;
    }
}

# 通常位于/var/log/nginx/error.log
tail -f /var/log/nginx/error.log

# 查看內存使用情況
free -h
 
# 查看CPU使用情況
top
 
# 檢查文件描述符限制
ulimit -n

# 使用curl測試上游服務響應時間
time curl -I http://127.0.0.1:8080  # 替換為實際上游地址

# 關鍵超時參數(shù)示例
location / {
    proxy_connect_timeout 60s;  # 連接超時時間
    proxy_send_timeout 60s;     # 發(fā)送請求超時時間
    proxy_read_timeout 120s;    # 讀取響應超時時間
    proxy_buffer_size 16k;
    proxy_buffers 4 32k;
}

# 檢查網絡延遲
ping 192.168.1.100  # 上游服務器IP
 
# 檢查網絡帶寬使用情況
iftop -i eth0

# 優(yōu)化代理配置
http {
    proxy_connect_timeout 30s;
    proxy_send_timeout 60s;
    proxy_read_timeout 60s;
    proxy_buffer_size 32k;
    proxy_buffers 4 32k;
    proxy_busy_buffers_size 64k;
    proxy_temp_file_write_size 64k;
    proxy_next_upstream error timeout invalid_header http_500 http_502 http_503 http_504;
}

# /etc/php-fpm.d/www.conf
pm.max_children = 50
pm.start_servers = 10
pm.min_spare_servers = 5
pm.max_spare_servers = 20

upstream backend {
    least_conn;  # 最少連接算法
    server backend1.example.com weight=5;
    server backend2.example.com weight=5;
    server backend3.example.com backup;  # 備份服務器
}

upstream backend {
    server backend1.example.com;
    server backend2.example.com;
    check interval=3000 rise=2 fall=5 timeout=1000 type=http;
    check_http_send "HEAD /health HTTP/1.0\r\n\r\n";
    check_http_expect_alive http_2xx http_3xx;
}

#!/bin/bash
 
# Nginx 502/504錯誤快速診斷腳本
 
# 顏色定義
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[0;33m'
NC='\033[0m' # No Color
 
echo -e "${YELLOW}=== Nginx 502/504錯誤診斷工具 ===${NC}"
 
# 檢查Nginx服務狀態(tài)
echo -e "\n${YELLOW}[1/5] 檢查Nginx服務狀態(tài):${NC}"
if systemctl is-active --quiet nginx; then
    echo -e "${GREEN}? Nginx服務正在運行${NC}"
else
    echo -e "${RED}? Nginx服務未運行${NC}"
    systemctl status nginx --no-pager
fi
 
# 檢查Nginx配置
echo -e "\n${YELLOW}[2/5] 檢查Nginx配置語法:${NC}"
nginx -t
NGINX_CONFIG_STATUS=$?
 
# 檢查上游服務器連通性
echo -e "\n${YELLOW}[3/5] 檢查上游服務器連通性:${NC}"
UPSTREAM=$(grep -r "proxy_pass" /etc/nginx/ | awk -F'[ ;]' '{print $3}' | sort -u)
for server in $UPSTREAM; do
    echo -e "\n測試上游服務器: ${server}"
    IP=$(echo $server | cut -d':' -f1)
    PORT=$(echo $server | cut -d':' -f2)
    
    if ping -c 1 $IP &>/dev/null; then
        echo -e "${GREEN}? ${IP} 網絡可達${NC}"
    else
        echo -e "${RED}? ${IP} 網絡不可達${NC}"
    fi
    
    if nc -z -w 2 $IP $PORT &>/dev/null; then
        echo -e "${GREEN}? ${IP}:${PORT} 端口可訪問${NC}"
    else
        echo -e "${RED}? ${IP}:${PORT} 端口不可訪問${NC}"
    fi
done
 
# 檢查Nginx錯誤日志
echo -e "\n${YELLOW}[4/5] 檢查最近的Nginx錯誤日志:${NC}"
if [ -f "/var/log/nginx/error.log" ]; then
    tail -n 20 /var/log/nginx/error.log | grep -iE "502|504|connect|refused|timeout" || echo "未發(fā)現(xiàn)最近的502/504相關錯誤"
else
    echo "錯誤日志文件不存在"
fi
 
# 檢查系統(tǒng)資源
echo -e "\n${YELLOW}[5/5] 檢查系統(tǒng)資源使用情況:${NC}"
echo -e "\n內存使用:"
free -h
echo -e "\nCPU使用:"
top -bn1 | head -n 5
echo -e "\n磁盤使用:"
df -h
 
echo -e "\n${YELLOW}=== 診斷完成 ===${NC}"