Nginx, like any software, can sometimes encounter errors. Some of the most common errors are related to configuration, permissions, or system limitations. Below are the most frequently seen errors, their causes, and potential solutions:
Cause: This error usually occurs when Nginx, acting as a reverse proxy, cannot communicate with the upstream server (e.g., an application server like PHP-FPM, Node.js, or other backend services).
Solutions:
nginx.conf, ensure that the proxy_pass directive is correctly set:location / {
proxy_pass http://127.0.0.1:8000;
}
/var/log/nginx/error.log and /var/log/nginx/access.log) for more specific details.buffer_size or timeout values if the backend server is slow to respond.Common fixes:
# Example of increasing timeout
proxy_read_timeout 90;
proxy_connect_timeout 90;
proxy_send_timeout 90;
proxy_connect_timeout 300;
proxy_send_timeout 300;
proxy_read_timeout 300;
send_timeout 300;
client_max_body_size in the Nginx configuration:server {
client_max_body_size 50M; # Example for 50MB
}
sudo systemctl reload nginx
www-data or nginx) has the correct permissions to access the files.sudo chown -R www-data:www-data /var/www/example
sudo chmod -R 755 /var/www/example
index directive is correctly configured, and make sure the index file (e.g., index.html) exists.deny all; directive in the relevant location block of the Nginx config.root or alias directive.try_files directive is configured correctly:location / {
try_files $uri $uri/ =404;
}
server_names_hash_bucket_size setting.server_names_hash_bucket_size in the Nginx configuration file:http {
server_names_hash_bucket_size 64;
}
/etc/nginx/nginx.conf:worker_rlimit_nofile 100000;
/etc/security/limits.conf:* soft nofile 100000
* hard nofile 100000
sudo lsof -i :80
server {
listen 443 ssl;
server_name example.com;
ssl_certificate /etc/ssl/certs/example.com.crt;
ssl_certificate_key /etc/ssl/private/example.com.key;
}
/var/log/nginx/error.log/var/log/nginx/access.logNginx’s error logs provide more detailed information about these errors, making it easier to diagnose and fix them.