Installing PHP

PHP originally stood for Personal Home Page, but of late it is referred to as Hypertext Preprocessor. It is a server-side scripting language designed for web development. It is one of the core standing pillars for the LAMP (Linux, Apache, MySQL, and PHP) or LEMP (Linux, Nginx, MySQL, and PHP) stack. Please keep in mind that there are multiple options for running PHP. The most common options available to you are mod_php , FastCGI, and PHP-FPM .

=> mod_php is the built-in version available only for Apache. Installing it is easy, and its ease of use coupled with tight integration is probably the most common reason to deploy mod_php. However, it forces every Apache child to use more memory and needs a restart of Apache to read an updated php.ini file.

=> FastCGI is a pretty generic protocol available on most platforms including Windows IIS. It is an improvisation over the earlier variation of Common Gateway Interface (CGI) that reduces the overheads by spinning up one process for multiple requests. You might be already aware that CGI used one process per request and it was not as scalable for extremely busy sites. FastCGI has a smaller memory footprint than mod_php and has more configuration options.

=> PHP-FPM is an alternative for PHP FastCGI implementation and is the newest kid on the block. It can be used with any web server that is compatible with FastCGI and plays well with Nginx too. It gives you a lot of configuration options and it really shines in multiple areas, especially related to availability. You can start different processes with different settings and different php.ini options. This means you can have multiple processes serving different versions of PHP in case your application is not compatible with a specific PHP version.

[root@localhost ~]# service php-fpm status
Redirecting to /bin/systemctl status php-fpm.service
Unit php-fpm.service could not be found.

[root@localhost ~]# yum install php-fpm

[root@localhost ~]# service php-fpm start

[root@localhost ~]# service php-fpm status
Redirecting to /bin/systemctl status php-fpm.service
● php-fpm.service – The PHP FastCGI Process Manager
Loaded: loaded (/usr/lib/systemd/system/php-fpm.service; disabled; vendor preset: disabled)
Active: active (running) since Wed 2017-09-06 19:11:52 IST; 1s ago
Main PID: 2953 (php-fpm)
Status: “Ready to handle connections”
CGroup: /system.slice/php-fpm.service
├─2953 php-fpm: master process (/etc/php-fpm.conf)
├─2954 php-fpm: pool www
├─2955 php-fpm: pool www
├─2956 php-fpm: pool www
├─2957 php-fpm: pool www
└─2958 php-fpm: pool www

[root@localhost ~]# ps -ef –forest |grep php-fpm
root 2972 2669 0 19:12 pts/0 00:00:00 \_ grep –color=auto php-fpm
root 2953 1 0 19:11 ? 00:00:00 php-fpm: master process (/etc/php-fpm.conf)
apache 2954 2953 0 19:11 ? 00:00:00 \_ php-fpm: pool www
apache 2955 2953 0 19:11 ? 00:00:00 \_ php-fpm: pool www
apache 2956 2953 0 19:11 ? 00:00:00 \_ php-fpm: pool www
apache 2957 2953 0 19:11 ? 00:00:00 \_ php-fpm: pool www
apache 2958 2953 0 19:11 ? 00:00:00 \_ php-fpm: pool www

[root@localhost ~]# php-fpm -v
PHP 5.4.16 (fpm-fcgi) (built: Nov 6 2016 00:30:57)
Copyright (c) 1997-2013 The PHP Group
Zend Engine v2.4.0, Copyright (c) 1998-2013 Zend Technologies

[root@localhost ~]# cat /etc/php-fpm.conf
;;;;;;;;;;;;;;;;;;;;;
; FPM Configuration ;
;;;;;;;;;;;;;;;;;;;;;

; All relative paths in this configuration file are relative to PHP’s install
; prefix.

; Include one or more files. If glob(3) exists, it is used to include a bunch of
; files from a glob(3) pattern. This directive can be used everywhere in the
; file.
include=/etc/php-fpm.d/*.conf

;;;;;;;;;;;;;;;;;;
; Global Options ;
;;;;;;;;;;;;;;;;;;

[global]
; Pid file
; Default Value: none
pid = /run/php-fpm/php-fpm.pid

; Error log file
; Default Value: /var/log/php-fpm.log
error_log = /var/log/php-fpm/error.log

; Log level
; Possible Values: alert, error, warning, notice, debug
; Default Value: notice
;log_level = notice

; If this number of child processes exit with SIGSEGV or SIGBUS within the time
; interval set by emergency_restart_interval then FPM will restart. A value
; of ‘0’ means ‘Off’.
; Default Value: 0
;emergency_restart_threshold = 0

; Interval of time used by emergency_restart_interval to determine when
; a graceful restart will be initiated. This can be useful to work around
; accidental corruptions in an accelerator’s shared memory.
; Available Units: s(econds), m(inutes), h(ours), or d(ays)
; Default Unit: seconds
; Default Value: 0
;emergency_restart_interval = 0

; Time limit for child processes to wait for a reaction on signals from master.
; Available units: s(econds), m(inutes), h(ours), or d(ays)
; Default Unit: seconds
; Default Value: 0
;process_control_timeout = 0

; Send FPM to background. Set to ‘no’ to keep FPM in foreground for debugging.
; Default Value: yes
daemonize = no

;;;;;;;;;;;;;;;;;;;;
; Pool Definitions ;
;;;;;;;;;;;;;;;;;;;;

; See /etc/php-fpm.d/*.conf

 

[root@localhost ~]# grep pm.start_servers /etc/php-fpm.d/www.conf
; pm.start_servers – the number of children created on startup.
pm.start_servers = 5

[root@localhost ~]# netstat -tlpn
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
tcp 0 0 127.0.0.1:9000 0.0.0.0:* LISTEN 2953/php-fpm: maste
tcp 0 0 0.0.0.0:80 0.0.0.0:* LISTEN 1353/nginx: master
tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 845/sshd
tcp 0 0 127.0.0.1:25 0.0.0.0:* LISTEN 1959/master
tcp6 0 0 :::80 :::* LISTEN 1353/nginx: master
tcp6 0 0 :::22 :::* LISTEN 845/sshd
tcp6 0 0 ::1:25 :::* LISTEN 1959/master

[root@localhost ~]# cat /etc/php-fpm.d/www.conf
; Start a new pool named ‘www’.
[www]

; 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 address on
; a specific port;
; ‘port’ – to listen on a TCP socket to all addresses on a
; specific port;
; ‘/path/to/unix/socket’ – to listen on a unix socket.
; Note: This value is mandatory.
listen = 127.0.0.1:9000

; Set listen(2) backlog. A value of ‘-1’ means unlimited.
; Default Value: -1
;listen.backlog = -1

; List of ipv4 addresses 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

; 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 0666
;listen.owner = nobody
;listen.group = nobody
;listen.mode = 0666

; Unix user/group of processes
; Note: The user is mandatory. If the group is not set, the default user’s group
; will be used.
; RPM: apache Choosed to be able to access some dir as httpd
user = apache
; RPM: Keep a group allowed to write in log dir.
group = apache

; 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:
; 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.
; 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 to be created when pm is set to ‘dynamic’.
; 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.
; Note: Used when pm is set to either ‘static’ or ‘dynamic’
; Note: This value is mandatory.
pm.max_children = 50

; 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 = 5

; 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 = 35

; 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. By default, the status page shows the following
; information:
; accepted conn – the number of request accepted by the pool;
; pool – the name of the pool;
; process manager – static or dynamic;
; idle processes – the number of idle processes;
; active processes – the number of active processes;
; total processes – the number of idle + active processes.
; The values of ‘idle processes’, ‘active processes’ and ‘total processes’ are
; updated each second. The value of ‘accepted conn’ is updated in real time.
; Example output:
; accepted conn: 12073
; pool: www
; process manager: static
; idle processes: 35
; active processes: 65
; total processes: 100
; By default the status page output is formatted as text/plain. Passing either
; ‘html’ or ‘json’ as a 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
; 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 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

; 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 log file for slow requests
; Default Value: not set
; Note: slowlog is mandatory if request_slowlog_timeout is set
slowlog = /var/log/php-fpm/www-slow.log

; 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: 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. This value must be an absolute path.
; Default Value: current directory or / when chroot
;chdir = /var/www

; 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.
; Default Value: no
;catch_workers_output = yes

; 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.

; 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 www@my.domain.com
;php_flag[display_errors] = off
php_admin_value[error_log] = /var/log/php-fpm/www-error.log
php_admin_flag[log_errors] = on
;php_admin_value[memory_limit] = 128M

; Set session path to a directory owned by process user
php_value[session.save_handler] = files
php_value[session.save_path] = /var/lib/php/session