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Need LEMP Admin - NGINX 502 Errors WordPress

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Hey, I've got a LEMP server running on Debian 8.x and occasionally I receive nginx bad gateway errors. The nginx log reports:

2016/01/24 06:26:12 [error] 18214#0: *2639761 connect() to unix:/var/run/php5-fpm.sock failed (11: Resource temporarily unavailable) while connecting to upstream, client: 180.76.15.29, server: www.farmfreshhealthyliving.com, request: "GET /?p=896 HTTP/1.1", upstream: "fastcgi://unix:/var/run/php5-fpm.sock:", host: "www.farmfreshhealthyliving.com"

I've checked the normal stuff to make sure the site config file and the www.conf file are using the same php5-fpm socket. I think I need to tune both my site and nginx config files, and I'm willing to pay someone for some advice on that.

My server has the following specs:

<blockquote>
- dedicated server
- quad-core Xeon
- 32GB RAM box
- Debian 8.x / LEMP (installed summer 2015)
- Using PHP5-FPM
</blockquote>

Current nginx.conf file:


user www-data;
worker_processes 8;
pid /run/nginx.pid;

events {
worker_connections 8096;
multi_accept on;
use epoll;
}

http {

##
# Basic Settings
##

sendfile on;
tcp_nopush on;
tcp_nodelay on;
keepalive_timeout 65;
types_hash_max_size 2048;
client_max_body_size 100m;
server_tokens off;

##
## custom additions by Kyler on Dec 2015
##
client_body_timeout 12;
client_header_timeout 12;
send_timeout 20;
fastcgi_read_timeout 300s;
client_body_buffer_size 10K;
client_header_buffer_size 1k;
large_client_header_buffers 4 32k;
## End custom additions by Kyler

# server_names_hash_bucket_size 64;
# server_name_in_redirect off;

include /etc/nginx/mime.types;
default_type application/octet-stream;

##
# SSL Settings
##

ssl_protocols TLSv1 TLSv1.1 TLSv1.2; # Dropping SSLv3, ref: POODLE
ssl_prefer_server_ciphers on;

##
# Logging Settings
##

access_log /var/log/nginx/access.log;
error_log /var/log/nginx/error.log;

## added by Kyler on Dec 1 2015
access_log off;


##
# Gzip Settings
##

gzip on;
gzip_disable "msie6";

gzip_vary on;
gzip_proxied any;
gzip_comp_level 6;
gzip_buffers 16 8k;
gzip_http_version 1.1;
gzip_min_length 1000;
gzip_types text/plain text/css application/json application/x-javascript text/xml application/xml application/xml+rss text/javascript;






##
# Gzip Settings
##

#gzip on;
#gzip_disable "msie6";

# gzip_vary on;
# gzip_proxied any;
# gzip_comp_level 6;
# gzip_buffers 16 8k;
# gzip_http_version 1.1;
# gzip_types text/plain text/css application/json application/javascript text/xml application/xml application/xml+rss text/javascript;

##
# Virtual Host Configs
##

include /etc/nginx/conf.d/*.conf;
include /etc/nginx/sites-enabled/*;
}


#mail {
# # See sample authentication script at:
# # http://wiki.nginx.org/ImapAuthenticateWithApachePhpScript
#
# # auth_http localhost/auth.php;
# # pop3_capabilities "TOP" "USER";
# # imap_capabilities "IMAP4rev1" "UIDPLUS";
#
# server {
# listen localhost:110;
# protocol pop3;
# proxy on;
# }
#
# server {
# listen localhost:143;
# protocol imap;
# proxy on;
# }
#}




Current site block configuration (this is the same for all sites on this box. i have about 90 sites):


##
# You should look at the following URL's in order to grasp a solid understanding
# of Nginx configuration files in order to fully unleash the power of Nginx.
# http://wiki.nginx.org/Pitfalls
# http://wiki.nginx.org/QuickStart
# http://wiki.nginx.org/Configuration
#
# Generally, you will want to move this file somewhere, and start with a clean
# file but keep this around for reference. Or just disable in sites-enabled.
#
# Please see /usr/share/doc/nginx-doc/examples/ for more detailed examples.
##

# Default server configuration
#
server {
listen 80;
listen [::]:80;

# SSL configuration
#
# listen 443 ssl default_server;
# listen [::]:443 ssl default_server;
#
# Self signed certs generated by the ssl-cert package
# Don't use them in a production server!
#
# include snippets/snakeoil.conf;

root /var/www/happystrongandhealthy.com/public_html;
access_log /var/www/happystrongandhealthy.com/logs/access.log;
error_log /var/www/happystrongandhealthy.com/logs/error.log;

# Add index.php to the list if you are using PHP
index index.php index.html;

server_name www.happystrongandhealthy.com happystrongandhealthy.com;

#location / {
# First attempt to serve request as file, then
# as directory, then fall back to displaying a 404.
# try_files $uri $uri/ =404;
#}


location / {
try_files $uri $uri/ /index.php?$args;
}


# pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
#
location ~ \.php$ {
include snippets/fastcgi-php.conf;
#
# # With php5-cgi alone:
# fastcgi_pass 127.0.0.1:9000;
# # With php5-fpm:
fastcgi_pass unix:/var/run/php5-fpm.sock;
}

# deny access to .htaccess files, if Apache's document root
# concurs with nginx's one
#
#location ~ /\.ht {
# deny all;
#}
}


# Virtual Host configuration for example.com
#
# You can move that to a different file under sites-available/ and symlink that
# to sites-enabled/ to enable it.
#
#server {
# listen 80;
# listen [::]:80;
#
# server_name example.com;
#
# root /var/www/example.com;
# index index.html;
#
# location / {
# try_files $uri $uri/ =404;
# }
#}



Current www.conf file:


; Start a new pool named 'www'.
; the variable $pool can we used in any directive and will be replaced by the
; pool name ('www' here)
[www]

; Per pool prefix
; It only applies on the following directives:
; - 'access.log'
; - 'slowlog'
; - 'listen' (unixsocket)
; - 'chroot'
; - 'chdir'
; - 'php_values'
; - 'php_admin_values'
; When not set, the global prefix (or /usr) applies instead.
; Note: This directive can also be relative to the global prefix.
; Default Value: none
;prefix = /path/to/pools/$pool

; Unix user/group of processes
; Note: The user is mandatory. If the group is not set, the default user's group
; will be used.
user = www-data
group = www-data

; The address on which to accept FastCGI requests.
; Valid syntaxes are:
; 'ip.add.re.ss:port' - to listen on a TCP socket to a specific IPv4 address on
; a specific port;
; '[ip:6:addr:ess]:port' - to listen on a TCP socket to a specific IPv6 address on
; a specific port;
; 'port' - to listen on a TCP socket to all IPv4 addresses on a
; specific port;
; '[::]:port' - to listen on a TCP socket to all addresses
; (IPv6 and IPv4-mapped) on a specific port;
; '/path/to/unix/socket' - to listen on a unix socket.
; Note: This value is mandatory.
listen = /var/run/php5-fpm.sock
listen.owner = www-data
listen.group = www-data

; Set listen(2) backlog.
; Default Value: 65535 (-1 on FreeBSD and OpenBSD)
;listen.backlog = 65535

; Set permissions for unix socket, if one is used. In Linux, read/write
; permissions must be set in order to allow connections from a web server. Many
; BSD-derived systems allow connections regardless of permissions.
; Default Values: user and group are set as the running user
; mode is set to 0660

;listen.mode = 0660
; When POSIX Access Control Lists are supported you can set them using
; these options, value is a comma separated list of user/group names.
; When set, listen.owner and listen.group are ignored
;listen.acl_users =
;listen.acl_groups =

; List of addresses (IPv4/IPv6) of FastCGI clients which are allowed to connect.
; Equivalent to the FCGI_WEB_SERVER_ADDRS environment variable in the original
; PHP FCGI (5.2.2+). Makes sense only with a tcp listening socket. Each address
; must be separated by a comma. If this value is left blank, connections will be
; accepted from any ip address.
; Default Value: any
;listen.allowed_clients = 127.0.0.1

; Specify the nice(2) priority to apply to the pool processes (only if set)
; The value can vary from -19 (highest priority) to 20 (lower priority)
; Note: - It will only work if the FPM master process is launched as root
; - The pool processes will inherit the master process priority
; unless it specified otherwise
; Default Value: no set
; process.priority = -19

; Choose how the process manager will control the number of child processes.
; Possible Values:
; static - a fixed number (pm.max_children) of child processes;
; dynamic - the number of child processes are set dynamically based on the
; following directives. With this process management, there will be
; always at least 1 children.
; pm.max_children - the maximum number of children that can
; be alive at the same time.
; pm.start_servers - the number of children created on startup.
; pm.min_spare_servers - the minimum number of children in 'idle'
; state (waiting to process). If the number
; of 'idle' processes is less than this
; number then some children will be created.
; pm.max_spare_servers - the maximum number of children in 'idle'
; state (waiting to process). If the number
; of 'idle' processes is greater than this
; number then some children will be killed.
; ondemand - no children are created at startup. Children will be forked when
; new requests will connect. The following parameter are used:
; pm.max_children - the maximum number of children that
; can be alive at the same time.
; pm.process_idle_timeout - The number of seconds after which
; an idle process will be killed.
; Note: This value is mandatory.
pm = dynamic

; The number of child processes to be created when pm is set to 'static' and the
; maximum number of child processes when pm is set to 'dynamic' or 'ondemand'.
; This value sets the limit on the number of simultaneous requests that will be
; served. Equivalent to the ApacheMaxClients directive with mpm_prefork.
; Equivalent to the PHP_FCGI_CHILDREN environment variable in the original PHP
; CGI. The below defaults are based on a server without much resources. Don't
; forget to tweak pm.* to fit your needs.
; Note: Used when pm is set to 'static', 'dynamic' or 'ondemand'
; Note: This value is mandatory.
pm.max_children = 25

; The number of child processes created on startup.
; Note: Used only when pm is set to 'dynamic'
; Default Value: min_spare_servers + (max_spare_servers - min_spare_servers) / 2
pm.start_servers = 5

; The desired minimum number of idle server processes.
; Note: Used only when pm is set to 'dynamic'
; Note: Mandatory when pm is set to 'dynamic'
pm.min_spare_servers = 3

; The desired maximum number of idle server processes.
; Note: Used only when pm is set to 'dynamic'
; Note: Mandatory when pm is set to 'dynamic'
pm.max_spare_servers = 5

; The number of seconds after which an idle process will be killed.
; Note: Used only when pm is set to 'ondemand'
; Default Value: 10s
;pm.process_idle_timeout = 10s;

; The number of requests each child process should execute before respawning.
; This can be useful to work around memory leaks in 3rd party libraries. For
; endless request processing specify '0'. Equivalent to PHP_FCGI_MAX_REQUESTS.
; Default Value: 0
;pm.max_requests = 500

; The URI to view the FPM status page. If this value is not set, no URI will be
; recognized as a status page. It shows the following informations:
; pool - the name of the pool;
; process manager - static, dynamic or ondemand;
; start time - the date and time FPM has started;
; start since - number of seconds since FPM has started;
; accepted conn - the number of request accepted by the pool;
; listen queue - the number of request in the queue of pending
; connections (see backlog in listen(2));
; max listen queue - the maximum number of requests in the queue
; of pending connections since FPM has started;
; listen queue len - the size of the socket queue of pending connections;
; idle processes - the number of idle processes;
; active processes - the number of active processes;
; total processes - the number of idle + active processes;
; max active processes - the maximum number of active processes since FPM
; has started;
; max children reached - number of times, the process limit has been reached,
; when pm tries to start more children (works only for
; pm 'dynamic' and 'ondemand');
; Value are updated in real time.
; Example output:
; pool: www
; process manager: static
; start time: 01/Jul/2011:17:53:49 +0200
; start since: 62636
; accepted conn: 190460
; listen queue: 0
; max listen queue: 1
; listen queue len: 42
; idle processes: 4
; active processes: 11
; total processes: 15
; max active processes: 12
; max children reached: 0
;
; By default the status page output is formatted as text/plain. Passing either
; 'html', 'xml' or 'json' in the query string will return the corresponding
; output syntax. Example:
; http://www.foo.bar/status
; http://www.foo.bar/status?json
; http://www.foo.bar/status?html
; http://www.foo.bar/status?xml
;
; By default the status page only outputs short status. Passing 'full' in the
; query string will also return status for each pool process.
; Example:
; http://www.foo.bar/status?full
; http://www.foo.bar/status?json&full
; http://www.foo.bar/status?html&full
; http://www.foo.bar/status?xml&full
; The Full status returns for each process:
; pid - the PID of the process;
; state - the state of the process (Idle, Running, ...);
; start time - the date and time the process has started;
; start since - the number of seconds since the process has started;
; requests - the number of requests the process has served;
; request duration - the duration in ┬Ás of the requests;
; request method - the request method (GET, POST, ...);
; request URI - the request URI with the query string;
; content length - the content length of the request (only with POST);
; user - the user (PHP_AUTH_USER) (or '-' if not set);
; script - the main script called (or '-' if not set);
; last request cpu - the %cpu the last request consumed
; it's always 0 if the process is not in Idle state
; because CPU calculation is done when the request
; processing has terminated;
; last request memory - the max amount of memory the last request consumed
; it's always 0 if the process is not in Idle state
; because memory calculation is done when the request
; processing has terminated;
; If the process is in Idle state, then informations are related to the
; last request the process has served. Otherwise informations are related to
; the current request being served.
; Example output:
; ************************
; pid: 31330
; state: Running
; start time: 01/Jul/2011:17:53:49 +0200
; start since: 63087
; requests: 12808
; request duration: 1250261
; request method: GET
; request URI: /test_mem.php?N=10000
; content length: 0
; user: -
; script: /home/fat/web/docs/php/test_mem.php
; last request cpu: 0.00
; last request memory: 0
;
; Note: There is a real-time FPM status monitoring sample web page available
; It's available in: /usr/share/php5/fpm/status.html
;
; Note: The value must start with a leading slash (/). The value can be
; anything, but it may not be a good idea to use the .php extension or it
; may conflict with a real PHP file.
; Default Value: not set
;pm.status_path = /status

; The ping URI to call the monitoring page of FPM. If this value is not set, no
; URI will be recognized as a ping page. This could be used to test from outside
; that FPM is alive and responding, or to
; - create a graph of FPM availability (rrd or such);
; - remove a server from a group if it is not responding (load balancing);
; - trigger alerts for the operating team (24/7).
; Note: The value must start with a leading slash (/). The value can be
; anything, but it may not be a good idea to use the .php extension or it
; may conflict with a real PHP file.
; Default Value: not set
;ping.path = /ping

; This directive may be used to customize the response of a ping request. The
; response is formatted as text/plain with a 200 response code.
; Default Value: pong
;ping.response = pong

; The access log file
; Default: not set
;access.log = log/$pool.access.log

; The access log format.
; The following syntax is allowed
; %%: the '%' character
; %C: %CPU used by the request
; it can accept the following format:
; - %{user}C for user CPU only
; - %{system}C for system CPU only
; - %{total}C for user + system CPU (default)
; %d: time taken to serve the request
; it can accept the following format:
; - %{seconds}d (default)
; - %{miliseconds}d
; - %{mili}d
; - %{microseconds}d
; - %{micro}d
; %e: an environment variable (same as $_ENV or $_SERVER)
; it must be associated with embraces to specify the name of the env
; variable. Some exemples:
; - server specifics like: %{REQUEST_METHOD}e or %{SERVER_PROTOCOL}e
; - HTTP headers like: %{HTTP_HOST}e or %{HTTP_USER_AGENT}e
; %f: script filename
; %l: content-length of the request (for POST request only)
; %m: request method
; %M: peak of memory allocated by PHP
; it can accept the following format:
; - %{bytes}M (default)
; - %{kilobytes}M
; - %{kilo}M
; - %{megabytes}M
; - %{mega}M
; %n: pool name
; %o: output header
; it must be associated with embraces to specify the name of the header:
; - %{Content-Type}o
; - %{X-Powered-By}o
; - %{Transfert-Encoding}o
; - ....
; %p: PID of the child that serviced the request
; %P: PID of the parent of the child that serviced the request
; %q: the query string
; %Q: the '?' character if query string exists
; %r: the request URI (without the query string, see %q and %Q)
; %R: remote IP address
; %s: status (response code)
; %t: server time the request was received
; it can accept a strftime(3) format:
; %d/%b/%Y:%H:%M:%S %z (default)
; %T: time the log has been written (the request has finished)
; it can accept a strftime(3) format:
; %d/%b/%Y:%H:%M:%S %z (default)
; %u: remote user
;
; Default: "%R - %u %t \"%m %r\" %s"
;access.format = "%R - %u %t \"%m %r%Q%q\" %s %f %{mili}d %{kilo}M %C%%"

; The log file for slow requests
; Default Value: not set
; Note: slowlog is mandatory if request_slowlog_timeout is set
;slowlog = log/$pool.log.slow

; The timeout for serving a single request after which a PHP backtrace will be
; dumped to the 'slowlog' file. A value of '0s' means 'off'.
; Available units: s(econds)(default), m(inutes), h(ours), or d(ays)
; Default Value: 0
;request_slowlog_timeout = 0

; The timeout for serving a single request after which the worker process will
; be killed. This option should be used when the 'max_execution_time' ini option
; does not stop script execution for some reason. A value of '0' means 'off'.
; Available units: s(econds)(default), m(inutes), h(ours), or d(ays)
; Default Value: 0
;request_terminate_timeout = 0

; Set open file descriptor rlimit.
; Default Value: system defined value
;rlimit_files = 1024

; Set max core size rlimit.
; Possible Values: 'unlimited' or an integer greater or equal to 0
; Default Value: system defined value
;rlimit_core = 0

; Chroot to this directory at the start. This value must be defined as an
; absolute path. When this value is not set, chroot is not used.
; Note: you can prefix with '$prefix' to chroot to the pool prefix or one
; of its subdirectories. If the pool prefix is not set, the global prefix
; will be used instead.
; Note: chrooting is a great security feature and should be used whenever
; possible. However, all PHP paths will be relative to the chroot
; (error_log, sessions.save_path, ...).
; Default Value: not set
;chroot =

; Chdir to this directory at the start.
; Note: relative path can be used.
; Default Value: current directory or / when chroot
chdir = /

; Redirect worker stdout and stderr into main error log. If not set, stdout and
; stderr will be redirected to /dev/null according to FastCGI specs.
; Note: on highloaded environement, this can cause some delay in the page
; process time (several ms).
; Default Value: no
;catch_workers_output = yes

; Clear environment in FPM workers
; Prevents arbitrary environment variables from reaching FPM worker processes
; by clearing the environment in workers before env vars specified in this
; pool configuration are added.
; Setting to "no" will make all environment variables available to PHP code
; via getenv(), $_ENV and $_SERVER.
; Default Value: yes
;clear_env = no

; Limits the extensions of the main script FPM will allow to parse. This can
; prevent configuration mistakes on the web server side. You should only limit
; FPM to .php extensions to prevent malicious users to use other extensions to
; exectute php code.
; Note: set an empty value to allow all extensions.
; Default Value: .php
;security.limit_extensions = .php .php3 .php4 .php5

; Pass environment variables like LD_LIBRARY_PATH. All $VARIABLEs are taken from
; the current environment.
; Default Value: clean env
;env[HOSTNAME] = $HOSTNAME
;env[PATH] = /usr/local/bin:/usr/bin:/bin
;env[TMP] = /tmp
;env[TMPDIR] = /tmp
;env[TEMP] = /tmp

; Additional php.ini defines, specific to this pool of workers. These settings
; overwrite the values previously defined in the php.ini. The directives are the
; same as the PHP SAPI:
; php_value/php_flag - you can set classic ini defines which can
; be overwritten from PHP call 'ini_set'.
; php_admin_value/php_admin_flag - these directives won't be overwritten by
; PHP call 'ini_set'
; For php_*flag, valid values are on, off, 1, 0, true, false, yes or no.

; Defining 'extension' will load the corresponding shared extension from
; extension_dir. Defining 'disable_functions' or 'disable_classes' will not
; overwrite previously defined php.ini values, but will append the new value
; instead.

; Note: path INI options can be relative and will be expanded with the prefix
; (pool, global or /usr)

; Default Value: nothing is defined by default except the values in php.ini and
; specified at startup with the -d argument
;php_admin_value[sendmail_path] = /usr/sbin/sendmail -t -i -f [email protected]
;php_flag[display_errors] = off
;php_admin_value[error_log] = /var/log/fpm-php.www.log
;php_admin_flag[log_errors] = on
;php_admin_value[memory_limit] = 32M

Answers (1)

2016-01-25

Vidyut Kale answers:

What is the output of

`ls -al /var/run/php5-fpm.sock`


Kyler Boudreau comments:

srw-rw---- 1 www-data www-data 0 Jan 25 09:29 /var/run/php5-fpm.sock