nginx

nginx
(pronounced "engine X"), is a free, open-source, high-performance HTTP
web server
and reverse proxy, as well as an IMAP/POP3 proxy server, written by Igor Sysoev in 2005. nginx is well known for its stability, rich feature set, simple configuration, and low resource consumption.
This article describes how to set up nginx and how to optionally integrate it with
PHP
via
#FastCGI
.
Installation
Install
nginx-mainline
or
nginx
.
Using the mainline branch is recommended. The main reason to use the stable branch is that you are concerned about possible impacts of new features, such as incompatibility with third-party modules or the inadvertent introduction of bugs in
new features
.
Note
All nginx modules available in the
official repositories
require the
nginx
package (as opposed to
nginx-mainline
) as a dependency. It may be wise to review the list of modules for any you might need/want before making the
nginx
vs
nginx-mainline
decision. Modules for
nginx-mainline
can be found in the
Arch User Repository
.
For a chroot-based installation for additional security, see
#Installation in a chroot
.
Tip
There are two popular drop-in forks:
angie
AUR
and
freenginx-mainline
AUR
.
Running
Start/enable
nginx.service
or
angie.service
if you use Angie.
The default page served at
http://127.0.0.1
is
/usr/share/nginx/html/index.html
.
Configuration
First steps with nginx are described in the
Beginner’s Guide
. You can modify the configuration by editing the files in
/etc/nginx/
The main configuration file is located at
/etc/nginx/nginx.conf
.
More details and examples can be found in the
official documentation
.
The examples below cover the most common use cases. It is assumed that you use the default location for documents (
/usr/share/nginx/html
). If that is not the case, substitute your path instead.
Tip
Nginx configuraton tools have been provided by
Digital Ocean
and
Mozilla
.
Configuration example
/etc/nginx/nginx.conf
user http;
worker_processes auto;
worker_cpu_affinity auto;

events {
    worker_connections 1024;
}

http {
    charset utf-8;
    sendfile on;
    tcp_nopush on;
    tcp_nodelay on;
    server_tokens off;
    log_not_found off;
    types_hash_max_size 4096;
    client_max_body_size 16M;

    # MIME
    include mime.types;
    default_type application/octet-stream;

    # logging
    access_log /var/log/nginx/access.log;
    error_log /var/log/nginx/error.log warn;

    # load configs
    include /etc/nginx/conf.d/*.conf;
    include /etc/nginx/sites-enabled/*;
}
General configuration
Processes and connections
You should choose a fitting value for
worker_processes
. This setting ultimately defines how many connections nginx will accept and how many processors it will be able to make use of. Generally, making it the number of hardware threads in your system is a good start. Alternatively,
worker_processes
accepts the
auto
value since versions 1.3.8 and 1.2.5, which will try to autodetect the optimal value (
source
).
The maximum connections nginx will accept is given by
max_clients = worker_processes * worker_connections
.
Running under different user
By default,
nginx
runs the master process as
root
and worker processes as user
http
. To run worker processes as another user, change the
user
directive in
nginx.conf
:
/etc/nginx/nginx.conf
user
user
[
group
];
If the group is omitted, a group whose name equals that of
user
is used.
Tip
It is also possible to run nginx without anything running as
root
using
systemd
. See
#Running unprivileged using systemd
and
#Running user service using systemd
.
Server blocks
It is possible to serve multiple domains using
server
blocks. These are comparable to "VirtualHosts" in
Apache HTTP Server
. Also see the
upstream examples
.
In the example below the server listens for incoming connections on IPv4 and IPv6 ports 80 for two domains,
domainname1.tld
and
domainname2.tld
:
/etc/nginx/nginx.conf
...
server {
    listen 80;
    listen [::]:80;
    server_name domainname1.tld;
    root /usr/share/nginx/domainname1.tld/html;
    location / {
        index index.php index.html index.htm;
    }
}

server {
    listen 80;
    listen [::]:80;
    server_name domainname2.tld;
    root /usr/share/nginx/domainname2.tld/html;
    ...
}
Restart
nginx.service
to apply any changes.
Note
Make sure the hostnames are resolvable by setting up a DNS-server like
BIND
or
dnsmasq
, or have a look at
Network configuration#Local network hostname resolution
.
Managing server entries
It is possible to put different
server
blocks in different files. This allows you to easily enable or disable certain sites.
The factual accuracy of this article or section is disputed.
Reason:
It is contested if the below approach using
sites-enabled
and
sites-available
is still useful and doesn't create more problems, see
comparing the two approaches
and
example of problems arising through sites-enabled and sites-available approach
.
Instead, one can just create files inside
etc/nginx/conf.d/
which adheres to the standard of drop in configuration files. Then, include
include /etc/nginx/conf.d/*.conf
in the main config file, similar to including other file patterns in other directories as shown below. This way, sites can be disabled just be renaming them to e.g.
original_name.conf.disabled
, since only files ending in
.conf
are included.
(Discuss in
Talk:Nginx
)
For using the
sites-enabled
and
sites-available
approach, create the following directories:
# mkdir /etc/nginx/sites-available
# mkdir /etc/nginx/sites-enabled
Create a file inside the
sites-available
directory that contains one or more server blocks:
/etc/nginx/sites-available/example.conf
server {
    listen 443 ssl;
    listen [::]:443 ssl;
    http2 on;

    ...
}
Append
include sites-enabled/*;
to the end of the
http
block:
/etc/nginx/nginx.conf
http {
    ...
    include sites-enabled/*;
}
To enable a site, simply create a symlink:
# ln -s /etc/nginx/sites-available/example.conf /etc/nginx/sites-enabled/example.conf
To disable a site, unlink the active symlink:
# unlink /etc/nginx/sites-enabled/example.conf
Reload
/
restart
nginx.service
to enable changes to the site's configuration.
TLS
This article or section needs language, wiki syntax or style improvements. See
Help:Style
for reference.
Reason:
Do not duplicate
OpenSSL#Usage
. (Discuss in
Talk:Nginx
)
OpenSSL
provides TLS support and is installed by default on Arch installations.
Tip
You may want to read the
ngx_http_ssl_module
documentation first before configuring SSL.
Let’s Encrypt
is a free, automated, and open certificate authority. A plugin is available to request valid SSL certificates straight from the command line and automatic configuration.
Mozilla has a useful
TLS article
as well as an
automated tool
to help create a more secure configuration.
Warning
If you plan on implementing TLS, know that some variations and implementations are
still vulnerable to attack
[1]
. For details on these current vulnerabilities within TLS and how to apply appropriate changes to nginx, visit
https://weakdh.org/sysadmin.html
Create a private key and self-signed certificate. This is adequate for most installations that do not require a
CSR
:
# mkdir /etc/nginx/ssl
# cd /etc/nginx/ssl
# openssl req -new -x509 -nodes -newkey rsa:4096 -keyout server.key -out server.crt -days 1095
# chmod 400 server.key
# chmod 444 server.crt
Note
The
-days
switch is optional and RSA keysize can be as low as 2048 (default).
If you need to create a CSR, follow these instructions instead of the above:
# mkdir /etc/nginx/ssl
# cd /etc/nginx/ssl
# openssl genpkey -algorithm RSA -pkeyopt rsa_keygen_bits:4096 -out server.key
# chmod 400 server.key
# openssl req -new -sha256 -key server.key -out server.csr
# openssl x509 -req -days 1095 -in server.csr -signkey server.key -out server.crt
Note
For more
openssl
options, read its man page
openssl(1ssl)
or peruse its
extensive documentation
.
A starting point for a
/etc/nginx/nginx.conf
with TLS is
Mozilla's SSL Configuration Generator
.
Restart
nginx.service
to apply any changes.
Per-user directories
To replicate Apache-style
~user
URLs to users'
~/public_html
directories, try the following. (Note: if both rules are used, below, the more-specific PHP rule must come first.)
/etc/nginx/nginx.conf
...
server {
    ...
    # PHP in user directories, e.g. http://example.com/~user/test.php
    location ~ ^/~(.+?)(/.+\.php)$ {
        alias          /home/$1/public_html$2;
        fastcgi_pass   unix:/run/php-fpm/php-fpm.sock;
        fastcgi_index  index.php;
        include        fastcgi.conf;
    }

    # User directories, e.g. http://example.com/~user/
    location ~ ^/~(.+?)(/.*)?$ {
        alias     /home/$1/public_html$2;
        index     index.html index.htm;
        autoindex on;
    }
    ...
}
...
See
#PHP implementation
for more information on PHP configuration with
nginx
.
Restart
nginx.service
to enable the new configuration.
FastCGI
FastCGI
, also FCGI, is a protocol for interfacing interactive programs with a web server. FastCGI is a variation on the earlier
Common Gateway Interface
(CGI); FastCGI's main aim is to reduce the overhead associated with interfacing the web server and CGI programs, allowing servers to handle more web page requests at once.
FastCGI technology is introduced into nginx to work with many external tools, e.g.
Perl
,
PHP
and
Python
.
PHP implementation
PHP-FPM
is the recommended solution to run as FastCGI server for
PHP
.
Install
php-fpm
and make sure
PHP
has been installed and configured correctly. The main configuration file of PHP-FPM is
/etc/php/php-fpm.conf
. For basic usage the default configuration should be sufficient.
Finally,
start/enable
php-fpm.service
.
You can also use
php-legacy-fpm
instead, see
#Using php-legacy
.
Note
If you
run nginx under a different user
, make sure that the PHP-FPM socket file is accessible by this user, or use a TCP socket.
If you run nginx in chrooted environment (chroot is
/srv/nginx-jail
, web pages are served at
/srv/nginx-jail/www
), you must modify the file
/etc/php/php-fpm.conf
to include the
chroot = /srv/nginx-jail
and
listen = /srv/nginx-jail/run/php-fpm/php-fpm.sock
directives within the pool section (a default one is
[www]
). Create the directory for the socket file, if missing. Moreover, for modules that are dynamically linked to dependencies, you will need to copy those dependencies to the chroot (e.g. for php-imagick, you will need to copy the ImageMagick libraries to the chroot, but not imagick.so itself).
nginx configuration
When serving a PHP web-application, a
location
for PHP-FPM should to be included in each
server block
[2]
, e.g.:
/etc/nginx/sites-available/example.conf
server {
    root /usr/share/nginx/html;

    location / {
        index index.html index.htm index.php;
    }

    location ~ \.php$ {
        # 404
        try_files $fastcgi_script_name =404;

        # default fastcgi_params
        include fastcgi_params;

        # fastcgi settings
        fastcgi_pass			unix:/run/php-fpm/php-fpm.sock;
        fastcgi_index			index.php;
        fastcgi_buffers			8 16k;
        fastcgi_buffer_size		32k;

        # fastcgi params
        fastcgi_param DOCUMENT_ROOT	$realpath_root;
        fastcgi_param SCRIPT_FILENAME	$realpath_root$fastcgi_script_name;
        #fastcgi_param PHP_ADMIN_VALUE	"open_basedir=$base/:/usr/lib/php/:/tmp/";
    }
}
If it is needed to process other extensions with PHP (e.g.
.html
and
.htm
):
location ~ [^/]\.(php|html|htm)(/|$) {
    ...
}
Non
.php
extension processing in PHP-FPM should also be explicitly added in
/etc/php/php-fpm.d/www.conf
:
security.limit_extensions = .php .html .htm
Note
Pay attention to the
fastcgi_pass
argument, as it must be the TCP or Unix socket defined by the chosen FastCGI server in its configuration file. The
default
(Unix) socket for
php-fpm
is:
fastcgi_pass unix:/run/php-fpm/php-fpm.sock;
You might use the common TCP socket,
not default
,
fastcgi_pass 127.0.0.1:9000;
Unix domain sockets should however be faster.
Tip
To allow multiple
server
blocks using the same PHP-FPM configuration, a
php_fastcgi.conf
configuration file may be used to ease management:
/etc/nginx/php_fastcgi.conf
location ~ \.php$ {
    # 404
    try_files $fastcgi_script_name =404;

    # default fastcgi_params
    include fastcgi_params;

    # fastcgi settings
    ...
}
To enable PHP support for a particular server, simply include the
php_fastcgi.conf
configuration file:
/etc/nginx/sites-available/example.conf
server {
    server_name example.com;
    ...

    include /etc/nginx/php_fastcgi.conf;
}
Test configuration
You need to
restart
the
php-fpm.service
and
nginx.service
units if the configuration has been changed in order to apply changes.
To test the FastCGI implementation, create a new PHP file inside the
root
folder containing:
<?php phpinfo(); ?>
Navigate this file inside a browser and you should see the informational page with the current PHP configuration.
CGI implementation
This implementation is needed for CGI applications.
fcgiwrap
Install
fcgiwrap
. The configuration is done by
editing
fcgiwrap.socket
.
Enable
and
start
fcgiwrap.socket
.
Multiple worker threads
If you want to spawn multiple worker threads, it is recommended that you use
multiwatch
AUR
, which will take care of restarting crashed children. You will need to use
spawn-fcgi
to create the Unix socket, as multiwatch seems unable to handle the systemd-created socket, even though fcgiwrap itself does not have any trouble if invoked directly in the unit file.
Override the unit
fcgiwrap.service
(and the
fcgiwrap.socket
unit, if present), and modify the
ExecStart
line to suit your needs. Here is a unit file that uses
multiwatch
AUR
. Make sure
fcgiwrap.socket
is not started or enabled, because it will conflict with this unit:
/etc/systemd/system/fcgiwrap.service
[Unit]
Description=Simple CGI Server
After=nss-user-lookup.target

[Service]
ExecStartPre=/bin/rm -f /run/fcgiwrap.socket
ExecStart=/usr/bin/spawn-fcgi -u http -g http -s /run/fcgiwrap.sock -n -- /usr/bin/multiwatch -f 10 -- /usr/sbin/fcgiwrap
ExecStartPost=/usr/bin/chmod 660 /run/fcgiwrap.sock
PrivateTmp=true
Restart=on-failure

[Install]
WantedBy=multi-user.target
Tweak
-f 10
to change the number of children that are spawned.
Warning
The
ExecStartPost
line is required because of strange behaviour I'm seeing when I use the
-M 660
option for
spawn-fcgi
. The wrong mode is set. This may be a bug?
nginx configuration
In
/etc/nginx
, copy the file
fastcgi_params
to
fcgiwrap_params
. In
fcgiwrap_params
, comment or delete the lines which set
SCRIPT_NAME
and
DOCUMENT_ROOT
.
Inside each
server
block serving a CGI web application should appear a
location
block similar to:
location ~ \.cgi$ {
     include       fcgiwrap_params;
     fastcgi_param DOCUMENT_ROOT /srv/www/cgi-bin/;
     fastcgi_param SCRIPT_NAME   myscript.cgi;
     fastcgi_pass  unix:/run/fcgiwrap.sock;
}
The default socket file for
fcgiwrap
is
/run/fcgiwrap.sock
.
Using
fastcgi_param SCRIPT_FILENAME /srv/www/cgi-bin/myscript.cgi
is a shortcut alternative to setting
DOCUMENT_ROOT
and
SCRIPT_NAME
. If you use
SCRIPT_FILENAME
, you also will not need to copy
fastcgi_params
to
fcgiwrap_params
and comment out the
DOCUMENT_ROOT
and
SCRIPT_NAME
lines.
Warning
If SCRIPT_NAME and DOCUMENT_ROOT are used, fcgiwrap will
discard
any other fastcgi_params set in nginx. You must use SCRIPT_FILENAME in order for other params (like PATH_INFO) to be settable through the Nginx configuration. See
this
GitHub issue.
If you keep getting a
502 - bad Gateway
error, you should check if your CGI-application first announces the mime-type of the following content. For HTML this needs to be
Content-type: text/html
.
If you get 403 errors, make sure that the CGI executable is readable and executable by the
http
user and that every parent folder is readable by the
http
user.
Installation in a chroot
The factual accuracy of this article or section is disputed.
Reason:
This section is from 2013. systemd has since been introduced and can be used instead, at much greater efficiency and without much hassle. (Discuss in
Talk:Nginx
)
Installing nginx in a
chroot
adds an additional layer of security. For maximum security the chroot should include only the files needed to run the nginx server and all files should have the most restrictive permissions possible, e.g., as much as possible should be owned by root, directories such as
/usr/bin
should be unreadable and unwritable, etc.
Arch comes with an
http
user and group by default which will run the server. The chroot will be in
/srv/http
.
A Perl script to create this jail is available at
jail.pl gist
. You can either use that or follow the instructions in this article. It expects to be run as root. You will need to uncomment a line before it makes any changes.
Create necessary devices
nginx needs
/dev/null
,
/dev/random
, and
/dev/urandom
. To install these in the chroot create the
/dev/
directory and add the devices with
mknod
. Avoid mounting all of
/dev/
to ensure that, even if the chroot is compromised, an attacker must break out of the chroot to access important devices like
/dev/sda1
.
Tip
Be sure that
/srv/http
is mounted without the nodev option
See
mknod(1)
and
ls -l /dev/{null,random,urandom}
to better understand the
mknod
options.
# export JAIL=/srv/http
# mkdir $JAIL/dev
# mknod -m 0666 $JAIL/dev/null c 1 3
# mknod -m 0666 $JAIL/dev/random c 1 8
# mknod -m 0444 $JAIL/dev/urandom c 1 9
Create necessary directories
nginx requires a bunch of files to run properly. Before copying them over, create the folders to store them. This assumes your nginx document root will be
/srv/http/www
.
# mkdir -p $JAIL/etc/nginx/logs
# mkdir -p $JAIL/usr/{lib,bin}
# mkdir -p $JAIL/usr/share/nginx
# mkdir -p $JAIL/var/{log,lib}/nginx
# mkdir -p $JAIL/www/cgi-bin
# mkdir -p $JAIL/{run,tmp}
# cd $JAIL; ln -s usr/lib lib
# cd $JAIL; ln -s usr/lib lib64
# cd $JAIL/usr; ln -s lib lib64
Then mount
$JAIL/tmp
and
$JAIL/run
as tmpfs's. The size should be limited to ensure an attacker cannot eat all the RAM.
# mount -t tmpfs none $JAIL/run -o 'noexec,size=1M'
# mount -t tmpfs none $JAIL/tmp -o 'noexec,size=100M'
In order to preserve the mounts across reboots, the following entries should be added to
/etc/fstab
:
/etc/fstab
tmpfs   /srv/http/run   tmpfs   rw,noexec,relatime,size=1024k   0       0
tmpfs   /srv/http/tmp   tmpfs   rw,noexec,relatime,size=102400k 0       0
Populate the chroot
First copy over the easy files.
# cp -r /usr/share/nginx/* $JAIL/usr/share/nginx
# cp -r /usr/share/nginx/html/* $JAIL/www
# cp /usr/bin/nginx $JAIL/usr/bin/
# cp -r /var/lib/nginx $JAIL/var/lib/nginx
Now copy over required libraries. Use
ldd
to list them and then copy them all to the correct location. Copying is preferred over hardlinks to ensure that even if an attacker gains write access to the files they cannot destroy or alter the true system files.
$ ldd /usr/bin/nginx
linux-vdso.so.1 (0x00007fffc41fe000)
libpthread.so.0 => /usr/lib/libpthread.so.0 (0x00007f57ec3e8000)
libcrypt.so.1 => /usr/lib/libcrypt.so.1 (0x00007f57ec1b1000)
libstdc++.so.6 => /usr/lib/libstdc++.so.6 (0x00007f57ebead000)
libm.so.6 => /usr/lib/libm.so.6 (0x00007f57ebbaf000)
libpcre.so.1 => /usr/lib/libpcre.so.1 (0x00007f57eb94c000)
libssl.so.1.0.0 => /usr/lib/libssl.so.1.0.0 (0x00007f57eb6e0000)
libcrypto.so.1.0.0 => /usr/lib/libcrypto.so.1.0.0 (0x00007f57eb2d6000)
libdl.so.2 => /usr/lib/libdl.so.2 (0x00007f57eb0d2000)
libz.so.1 => /usr/lib/libz.so.1 (0x00007f57eaebc000)
libGeoIP.so.1 => /usr/lib/libGeoIP.so.1 (0x00007f57eac8d000)
libgcc_s.so.1 => /usr/lib/libgcc_s.so.1 (0x00007f57eaa77000)
libc.so.6 => /usr/lib/libc.so.6 (0x00007f57ea6ca000)
/lib64/ld-linux-x86-64.so.2 (0x00007f57ec604000)
For files residing in
/usr/lib
you may try the following one-liner:
# cp $(ldd /usr/bin/nginx | grep /usr/lib/ | sed -sre 's/(.+)(\/usr\/lib\/\S+).+/\2/g') $JAIL/usr/lib
And the following for
ld-linux-x86-64.so
:
# cp /lib64/ld-linux-x86-64.so.2 $JAIL/lib
Note
Do not try to copy
linux-vdso.so
: it is not a real library and does not exist in
/usr/lib
.
Copy over some miscellaneous but necessary libraries and system files.
# cp /usr/lib/libnss_* $JAIL/usr/lib
# cp -rfvL /etc/{services,localtime,nsswitch.conf,nscd.conf,protocols,hosts,ld.so.cache,ld.so.conf,resolv.conf,host.conf,nginx} $JAIL/etc
Create restricted user/group files for the chroot. This way only the users needed for the chroot to function exist as far as the chroot knows, and none of the system users/groups are leaked to attackers should they gain access to the chroot.
$JAIL/etc/group
http:x:33:
nobody:x:99:
$JAIL/etc/passwd
http:x:33:33:http:/:/bin/false
nobody:x:99:99:nobody:/:/bin/false
$JAIL/etc/shadow
http:x:14871::::::
nobody:x:14871::::::
$JAIL/etc/gshadow
http:::
nobody:::
# touch $JAIL/etc/shells
# touch $JAIL/run/nginx.pid
Finally, make set very restrictive permissions. As much as possible should be owned by root and set unwritable.
# chown -R root:root $JAIL/

# chown -R http:http $JAIL/www
# chown -R http:http $JAIL/etc/nginx
# chown -R http:http $JAIL/var/{log,lib}/nginx
# chown http:http $JAIL/run/nginx.pid

# find $JAIL/ -gid 0 -uid 0 -type d -print | xargs chmod -rw
# find $JAIL/ -gid 0 -uid 0 -type d -print | xargs chmod +x
# find $JAIL/etc -gid 0 -uid 0 -type f -print | xargs chmod -x
# find $JAIL/usr/bin -type f -print | xargs chmod ug+rx
# find $JAIL/ -group http -user http -print | xargs chmod o-rwx
# chmod +rw $JAIL/tmp
# chmod +rw $JAIL/run
If your server will bind port 80 (or any other port in range [1-1023]), give the chrooted executable permission to bind these ports without root.
# setcap 'cap_net_bind_service=+ep' $JAIL/usr/bin/nginx
Modify nginx.service to start chroot
Override the unit
nginx.service
. Upgrading nginx will not modify your custom
.service
file.
The systemd unit must be changed to start up nginx in the chroot, as the http user, and store the PID file in the chroot.
Note
I'm not sure if the pid file needs to be stored in the chroot jail.
/etc/systemd/system/nginx.service
[Unit]
Description=A high performance web server and a reverse proxy server
After=network.target

[Service]
Type=forking
PIDFile=/srv/http/run/nginx.pid
ExecStartPre=/usr/bin/chroot --userspec=http:http /srv/http /usr/bin/nginx -t -q -g 'pid /run/nginx.pid; daemon on; master_process on;'
ExecStart=/usr/bin/chroot --userspec=http:http /srv/http /usr/bin/nginx -g 'pid /run/nginx.pid; daemon on; master_process on;'
ExecReload=/usr/bin/chroot --userspec=http:http /srv/http /usr/bin/nginx -g 'pid /run/nginx.pid; daemon on; master_process on;' -s reload
ExecStop=/usr/bin/chroot --userspec=http:http /srv/http /usr/bin/nginx -g 'pid /run/nginx.pid;' -s quit

[Install]
WantedBy=multi-user.target
Note
Upgrading nginx with pacman will not upgrade the chrooted nginx installation. You have to take care of the updates manually by repeating some of the steps above. Do not forget to also update the libraries it links against.
You can now safely get rid of the non-chrooted nginx installation.
# pacman -Rsc nginx
If you do not remove the non-chrooted nginx installation, you may want to make sure that the running nginx process is in fact the chrooted one. You can do so by checking where
/proc/
PID
/root
symlinks to. It should link to
/srv/http
instead of
/
.
# ps -C nginx | awk '{print $1}' | sed 1d | while read -r PID; do ls -l /proc/$PID/root; done
Tips and tricks
Running unprivileged using systemd
Use a
drop-in unit file
for
nginx.service
and set the
User
and optionally
Group
options under
[Service]
:
/etc/systemd/system/nginx.service.d/user.conf
[Service]
User=
user
Group=
group
We can harden the service against ever elevating privileges:
/etc/systemd/system/nginx.service.d/user.conf
[Service]
...
NoNewPrivileges=yes
Tip
See
systemd.exec(5)
for more options of confinement.
Then we need to ensure that
user
has access to everything it needs. Follow the subsections below and then
start
nginx.
Tip
The same setup may be desirable for your
FastCGI server
as well.
Port
Linux does not permit non-
root
processes to bind to ports below 1024 by default. A port above 1024 can be used:
/etc/nginx/nginx.conf
server {
        listen 8080;
}
Tip
If you want nginx accessible on port 80 or 443, configure your
firewall
to redirect requests from 80 or 443 to the ports nginx listens to.
Or you may grant the nginx process the CAP_NET_BIND_SERVICE capability which allows it to bind to ports below 1024:
/etc/systemd/system/nginx.service.d/user.conf
[Service]
...
CapabilityBoundingSet=
CapabilityBoundingSet=CAP_NET_BIND_SERVICE
AmbientCapabilities=
AmbientCapabilities=CAP_NET_BIND_SERVICE
Alternatively, you can use systemd socket activation. In this case, systemd will listen on the ports and, when a connection is made, spawn nginx passing the socket as a file descriptor. This means nginx requires no special capabilities as the socket already exists when it is started. This relies on an internal environment variable that nginx uses for passing sockets
[3]
and is therefore not officially supported. Instead of setting
CapabilityBoundingSet
and
AmbientCapabilities
, edit the service override to set the
NGINX
environment variable to tell nginx which file descriptors the sockets will be passed as:
/etc/systemd/system/nginx.service.d/user.conf
[Service]
...
Environment=NGINX=3:4;
There will be one socket per listening port starting at file descriptor 3, so in this example we are telling nginx to expect two sockets. Now create an
nginx.socket
unit specifying what ports to listen on:
/etc/systemd/system/nginx.socket
[Socket]
ListenStream=0.0.0.0:80
ListenStream=0.0.0.0:443
After=network.target
Requires=network.target

[Install]
WantedBy=sockets.target
The sockets will be passed in the order defined in this unit, so port 80 will be file descriptor 3 and port 443 will be file descriptor 4. If you previously enabled or started the service, you should now
stop
it, and
enable
nginx.socket
instead. When your system starts, nginx will not be running, but will be started when you access the website in a browser. With this you can harden the service further; for example, in many cases you can now set
PrivateNetwork=True
in the service file, blocking nginx from the external network, since the socket created by systemd is sufficient to serve the website over. Note that this will print a warning in the logs of the nginx service:
2020/08/29 19:33:20 [notice] 254#254: using inherited sockets from "3:4;"
PID file
nginx
is compiled to use
/run/nginx.pid
by default, which
user
cannot write to. We can create a directory that
user
can write to and place the PID file there. This can for example be done with
RuntimeDirectory
(
systemd.exec(5)
).
Edit
nginx.service
to configure the PID file:
/etc/systemd/system/nginx.service.d/user.conf
[Service]
...
RuntimeDirectory=nginx
PIDFile=/run/nginx/nginx.pid
ExecStart=
ExecStart=/usr/bin/nginx -g 'pid /run/nginx/nginx.pid; error_log stderr;' 
ExecReload=
ExecReload=/usr/bin/nginx -s reload -g 'pid /run/nginx/nginx.pid; error_log stderr;'
/var/lib/nginx
nginx
is compiled to store temp files in
/var/lib/nginx
by default.
Tip
See all compiled-in options by running
$ nginx -V
You can give
user
write access to this directory by for example using
StateDirectory
(
systemd.exec(5)
):
/etc/systemd/system/nginx.service.d/user.conf
[Service]
...
StateDirectory=nginx
/var/log/nginx
nginx
is compiled to store access logs in
/var/log/nginx
by default.
You can give
user
write access to this directory by for example using
LogsDirectory
(
systemd.exec(5)
):
/etc/systemd/system/nginx.service.d/user.conf
[Service]
...
LogsDirectory=nginx
Running user service using systemd
If you want to run a server instance fully controlled and configurable by unprivileged user, here is an example of a systemd user service.
~/.config/systemd/user/nginx.service
[Unit]
Description=A high performance web server and a reverse proxy server

[Service]
Type=forking
PIDFile=nginx.pid
SyslogLevel=err

ExecStart=nginx -g 'pid "%t/nginx.pid"; error_log stderr;' -c '%E/nginx/nginx.conf' -p '%D/nginx'
ExecReload=nginx -g 'pid "%t/nginx.pid"; error_log stderr;' -s reload
KillMode=mixed

[Install]
WantedBy=default.target
It reads config from
$XDG_CONFIG_HOME/nginx/nginx.conf
and uses
$XDG_DATA_HOME/nginx
as a working directory.
Alternative script for systemd
On pure systemd you can get advantages of chroot + systemd.
[4]
Based on set
user group
and pid with:
/etc/nginx/nginx.conf
user http;
pid /run/nginx.pid;
the absolute path of the file is
/srv/http/etc/nginx/nginx.conf
.
/etc/systemd/system/nginx.service
[Unit]
Description=nginx (Chroot)
After=network.target

[Service]
Type=forking
PIDFile=/srv/http/run/nginx.pid
RootDirectory=/srv/http
ExecStartPre=/usr/bin/nginx -t -c /etc/nginx/nginx.conf
ExecStart=/usr/bin/nginx -c /etc/nginx/nginx.conf
ExecReload=/usr/bin/nginx -c /etc/nginx/nginx.conf -s reload
ExecStop=/usr/bin/nginx -c /etc/nginx/nginx.conf -s stop

[Install]
WantedBy=multi-user.target
It is not necessary to set the default location, nginx loads at default
-c /etc/nginx/nginx.conf
, but it is a good idea.
Alternatively you can run
only
ExecStart
as chroot with parameter
RootDirectoryStartOnly
set as
yes
(see
systemd.service(5)
) or start it before mount point as effective or a systemd path (see
systemd.path(5)
) is available.
/etc/systemd/system/nginx.path
[Unit]
Description=nginx (Chroot) path
[Path]
PathExists=/srv/http/site/Public_html
[Install]
WantedBy=default.target
Enable
the created
nginx.path
and change the
WantedBy=default.target
to
WantedBy=nginx.path
in
/etc/systemd/system/nginx.service
.
The
PIDFile
in unit file allows systemd to monitor process (absolute path required). If it is undesired, you can change to default one-shot type, and delete the reference from the unit file.
Nginx beautifier
nginxbeautifier
AUR
is a commandline tool used to beautify and format nginx configuration files.
Gixy static config analyzer
gixy-next
AUR
is a fork of stale Yandex Gixy — security and performance issues analyzer of Nginx configuration. By default it reads
/etc/nginx/nginx.conf
only. Full config can be obtained and analyzed with following commands:
# nginx -T > nginx_full.conf
$ gixy nginx_full.conf
Better headers management
Nginx has a rather unintuitive header management system where headers can only be defined in one context, any other headers are ignored. To remedy this we can install the
headers-more-nginx
module.
Install
the package
nginx-mod-headers-more
package. This will install the module to
/usr/lib/nginx/modules
directory.
To load the module add the following to the top of your main nginx configuration file.
/etc/nginx/nginx.conf
load_module "/usr/lib/nginx/modules/ngx_http_headers_more_filter_module.so";
...
Basic Authentication
Basic authentication requires creation of a password file. The password file can be managed using
htpasswd
program provided by the
apache
package or using
nginx_passwd
AUR
which provides
nginx-passwd
- details available on
GitHub source
Using php-legacy
Install
php-legacy-fpm
instead of
php-fpm
and make sure
PHP
has been installed and configured correctly.
The main configuration file of PHP-LEGACY-FPM is
/etc/php-legacy/php-fpm.conf
. For basic usage the default configuration should be sufficient.
The Unix socket for the
fastcgi_pass
argument also needs to be adjusted, usually it is:
fastcgi_pass unix:/run/php-fpm-legacy/php-fpm.sock;
Then
start/enable
php-legacy-fpm.service
.
Troubleshooting
Configuration validation
# nginx -t
nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
nginx: configuration file /etc/nginx/nginx.conf test is successful
Error: The page you are looking for is temporarily unavailable. Please try again later. (502 Bad Gateway)
This is because the FastCGI server has not been started, or the socket used has wrong permissions.
Try
out this answer
to fix the 502 error.
In Arch Linux, the configuration file mentioned in above link is
/etc/php/php-fpm.conf
.
Error: No input file specified
1. Verify that variable
open_basedir
in
/etc/php/php.ini
contains the correct path specified as
root
argument in
nginx.conf
(usually
/usr/share/nginx/
). When using
PHP-FPM
as FastCGI server for PHP, you may add
fastcgi_param PHP_ADMIN_VALUE "open_basedir=$document_root/:/tmp/:/proc/";
in the
location
block which aims for processing PHP file in
nginx.conf
.
2. Another occasion is that, wrong
root
argument in the
location ~ \.php$
section in
nginx.conf
. Make sure the
root
points to the same directory as it in
location /
in the same server. Or you may just set root as global, do not define it in any location section.
3. Check permissions: e.g.
http
for user/group,
755
for directories and
644
for files. Remember the entire path to the
html
directory should have the correct permissions. See
File permissions and attributes#Bulk chmod
to bulk modify a directory tree.
4. You do not have the
SCRIPT_FILENAME
containing the full path to your scripts. If the configuration of nginx (
fastcgi_param SCRIPT_FILENAME
) is correct, this kind of error means PHP failed to load the requested script. Usually it is simply a permissions issue, you can just run php-cgi as root:
# spawn-fcgi -a 127.0.0.1 -p 9000 -f /usr/bin/php-cgi
or you should create a group and user to start the php-cgi:
# groupadd www
# useradd -g www www
# chmod +w /srv/www/nginx/html
# chown -R www:www /srv/www/nginx/html
# spawn-fcgi -a 127.0.0.1 -p 9000 -u www -g www -f /usr/bin/php-cgi
5. If you are running php-fpm with chrooted nginx ensure
chroot
is set correctly within
/etc/php-fpm/php-fpm.d/www.conf
(or
/etc/php-fpm/php-fpm.conf
if working on older version)
Warning: Could not build optimal types_hash
When starting the
nginx.service
, the process might log the message:
[warn] 18872#18872: could not build optimal types_hash, you should increase either types_hash_max_size: 1024 or types_hash_bucket_size: 64; ignoring types_hash_bucket_size
To fix this warning, increase the values for these keys inside the
http
block
[5]
[6]
:
/etc/nginx/nginx.conf
http {
    types_hash_max_size 4096;
    server_names_hash_bucket_size 128;
    ...
}
Cannot assign requested address
The full error from
nginx.service
unit status
is
[emerg] 460#460: bind() to A.B.C.D:443 failed (99: Cannot assign requested address)
Even if your nginx unit-file is configured to run after
network.target
with systemd, nginx may attempt to listen at an address that is configured but not added to any interface yet. Verify that this the case by manually running
start
for nginx (thereby showing the IP address is configured properly). Configuring nginx to listen to any address will resolve this issue. Now if your use case requires listening to a specific address, one possible solution is to reconfigure systemd.
To start nginx after all configured network devices are up and assigned an IP address, append
network-online.target
to
After=
within
nginx.service
and
start/enable
systemd-networkd-wait-online.service
.
See also
WebDAV with nginx
nginx configuration pitfalls
Very good in-depth 2014 look at nginx security and Reverse Proxying
Installing LEMP (nginx, PHP, MySQL with MariaDB engine and PhpMyAdmin) in Arch Linux
Using SSL certificates generated with Let's Encrypt