user www www;
worker_processes 2;

error_log /var/log/nginx-error.log info;

events {
    use kqueue;
    worker_connections 2048;
}

...

daemon on;

Determines whether nginx should become a daemon. Mainly used during development.

Enables debugging log for selected client connections. Other connections will use logging level set by the error_log directive. Debugged connections are specified by IPv4 or IPv6 (1.3.0) address or network. A connection may also be specified using a hostname, in which case the first IPv4 address corresponding to a name is used. For connections using UNIX-domain sockets (1.3.0), debugging log is enabled by the “unix:” parameter.

events {
    debug_connection 127.0.0.1;
    debug_connection localhost;
    debug_connection 192.0.2.0/24;
    debug_connection ::1;
    debug_connection 2001:0db8::/32;
    debug_connection unix:;
    ...
}

For this directive to work, nginx needs to be built with --with-debug.

error_log logs/error.log error;

Configures logging.

The first parameter defines a file that will store the log. The special value stderr selects the standard error file.

The second parameter determines the level of logging. Log levels above are listed in the order of increasing severity. Setting a certain log level will cause all messages of the specified and more severe log levels to be logged. For example, the default level error will cause error, crit, alert, and emerg messages to be logged. If this parameter is omitted then error is used.

For debug logging to work, nginx needs to be built with --with-debug.

env TZ;

Allows to limit a set of environment variables, change their values, or create new environment variables, for the following cases:

• variable inheritance during a live upgrade of an executable file;
• use of variables by the module ngx_http_perl_module;
• use of variables by worker processes. Please bear in mind that controlling system libraries in this way is not always possible as it is not uncommon for libraries to check variables only during initialization, well before they can be set using this directive. An exception from this is an above mentioned live upgrade of an executable file.

The TZ variable is always inherited and made available to the module ngx_http_perl_module, unless configured explicitly.

Usage example:

env MALLOC_OPTIONS;
env PERL5LIB=/data/site/modules;
env OPENSSL_ALLOW_PROXY_CERTS=1;

The NGINX environment variable is used internally by nginx and should not be set directly by the user.

Includes another file, or files matching the specified mask, into configuration. Included files should consist of syntactically correct directives and blocks.

Usage example:

include mime.types;
include vhosts/*.conf;

master_process on;

Determines whether worker processes are started. This directive is intended for nginx developers.

pcre_jit off;

Enables or disables the use of “just-in-time compilation” (PCRE JIT) for regular expressions known at configuration parse time.

PCRE JIT can speed up processing of regular expressions significantly.

The JIT is available in PCRE libraries starting from version 8.20 built with the --enable-jit configuration parameter. When building the PCRE library with nginx (--with-pcre=), the JIT support should be enabled with the --with-pcre-jit configuration parameter.

pid nginx.pid;

Defines a file that will store the process ID of the main process.

Defines the name of the hardware SSL accelerator.

Reduces timer resolution in worker processes, thus reducing the number of gettimeofday() system calls made. By default, gettimeofday() is called each time on receiving a kernel event. With reduced resolution, gettimeofday() is only called once per specified interval.

Example:

timer_resolution 100ms;

An internal implementation of interval depends on the method used:

• an EVFILT_TIMER filter if kqueue is used;
• timer_create() if eventport is used;
• setitimer() otherwise.

user nobody nobody;

Defines user and group credentials used by worker processes. If group is omitted, a group whose name equals that of user is used.

Binds worker processes to the sets of CPUs. Each CPU set is represented by a bitmask of allowed to use CPUs. There should be a separate set defined for each of the worker processes. By default, worker processes are not bound to any specific CPUs.

For example,

worker_processes    4;
worker_cpu_affinity 0001 0010 0100 1000;

binds each worker process to a separate CPU, while

worker_processes    2;
worker_cpu_affinity 0101 1010;

binds the first worker process to CPU0/CPU2, and the second worker process to CPU1/CPU3. The second example is suitable for hyper-threading.

The directive is only available on FreeBSD and Linux.

worker_priority 0;

Defines a scheduling priority for worker processes like is done by the nice command: a negative number means higher priority. Allowed range normally varies from -20 to 20.

Example:

worker_priority -10;

worker_processes 1;

Defines the number of worker processes.

The optimal value depends on many factors including (but not limited to) the number of CPU cores, the number of hard disk drives that store data, and load pattern. When in doubt, setting it to the number of available CPU cores would be a good start.

Changes the limit on the largest size of a core file (RLIMIT_CORE) for worker processes. Used to increase the limit without restarting the main process.

Changes the limit on the maximum number of open files (RLIMIT_NOFILE) for worker processes. Used to increase the limit without restarting the main process.

Defines a current working directory for a worker process. It is primarily used when writing a core-file, in which case a worker process should have write permission for the specified directory.