How to change limits in the Nginx configuration…

Changing limits in Nginx configuration can be done by editing the configuration files, usually located in /etc/nginx/ or /usr/local/nginx/conf/.

Here are common limits and how to change them:

Request body size limit (client_max_body_size): Sets the maximum allowed size of the client request body. Important for file uploads.
```
# In the context of http, server, or location
client_max_body_size 10M; # Example: set limit to 10 megabytes
```

Connection limit (worker_connections): Sets the maximum number of simultaneous connections that a worker process can handle.

# In the context of events
events {
    worker_connections 1024; # Example: 1024 connections per process
    # other event settings...
}

Connection timeout (keepalive_timeout): Sets the time during which a keep-alive connection with a client remains open after the last request.
```
# In the context of http, server, or location
keepalive_timeout 60s; # Example: 60 seconds
```
Header timeout (client_header_timeout): Time to wait for the client to send the request header. If the client does not send the header within this time, the connection is closed.
```
# In the context of http, server, or location
client_header_timeout 60s; # Example: 60 seconds
```
Request body send timeout (client_body_timeout): Time to wait for the client to send the request body. If the client does not send the body within this time, the connection is closed.
```
# In the context of http, server, or location
client_body_timeout 60s; # Example: 60 seconds
```
Proxy response timeout (proxy_read_timeout): Time to wait for a response from the proxied server.
```
# In the context of http, server, or location
proxy_read_timeout 120s; # Example: 120 seconds
```
Open files limit (worker_rlimit_nofile): Sets the maximum number of open files for a worker process. Important for handling many connections.
```
# In the main context
worker_rlimit_nofile 65535; # Example: 65535 files
```
Note: Adjusting this limit may also require setting system-level limits (ulimit).

Steps to change:

Determine which limit to change and in which context (http, server, location, events, main).
Find the relevant configuration file (usually nginx.conf or files in conf.d/ or sites-available/sites-enabled).

Add or modify the directive with the desired value.

# Example of adding in a server block
server {
    listen 80;
    server_name example.com;

    client_max_body_size 50M; # Change request body size limit for this server

    location / {
        # ...
    }
}

Check configuration syntax:
```
nginx -t
```

Reload Nginx to apply changes:

sudo systemctl reload nginx
# or
sudo service nginx reload

When changing limits, it is important to understand their purpose and potential impact on performance and security.

How to change limits in the Nginx configuration?