php-fpm启动，重启，退出

首先确保php-fpm正常安装，运行命令php-fpm -t输出查看：

##确定php-fpm配置正常
[root@iz2vcf47jzvf8dxrapolf7z php7.3.10]# /usr/local/php7.3.10/sbin/php-fpm -t
[-Oct-::] NOTICE: configuration file /usr/local/php7.3.10/etc/php-fpm.conf test is successful
##启动php-fpm
[root@izj6c0ct64t9oyhoeow593z php7.3.10]# ps -ef|grep php
root      1621  1603  0 09:31 pts/0    00:00:00 grep --color=auto php
[root@izj6c0ct64t9oyhoeow593z php7.3.10]# /usr/local/php7.3.10/sbin/php-fpm
[root@izj6c0ct64t9oyhoeow593z php7.3.10]# ps -ef|grep php|grep -v 'grep'
root      1626     1  0 09:32 ?        00:00:00 php-fpm: master process (/usr/local/php7.3.10/etc/php-fpm.conf)
www       1627  1626  0 09:32 ?        00:00:00 php-fpm: pool www
www       1628  1626  0 09:32 ?        00:00:00 php-fpm: pool www

##重启php-fpm（进程ID已改变）
[root@izj6c0ct64t9oyhoeow593z php7.3.10]# kill -SIGUSR2 `cat /usr/local/php7.3.10/var/run/php-fpm.pid`
[root@izj6c0ct64t9oyhoeow593z php7.3.10]# ps -ef|grep php|grep -v 'grep'
root      1651     1  0 09:36 ?        00:00:00 php-fpm: master process (/usr/local/php7.3.10/etc/php-fpm.conf)
www       1652  1651  0 09:36 ?        00:00:00 php-fpm: pool www
www       1653  1651  0 09:36 ?        00:00:00 php-fpm: pool www

##关闭php-fpm进程
[root@izj6c0ct64t9oyhoeow593z php7.3.10]# kill -SIGINT `cat /usr/local/php7.3.10/var/run/php-fpm.pid` && ps -ef|grep php|grep -v 'grep'
[root@izj6c0ct64t9oyhoeow593z php7.3.10]# ps -ef|grep fpm
root      1682  1603  0 09:41 pts/0    00:00:00 grep --color=auto fpm

可以把上面命令配置到~/.bashrc文件或/etc/bashrc文件，以快捷方式执行命令。(注意cat两端特殊字符是`不是单引号')

上面SIGUASR2和SIGINT是linux信号常量，而信号是进程在运行过程中，由自身产生或由进程外部发过来的消息（事件）。
      信号是硬件中断的软件模拟(软中断)。每个信号用一个整型常量宏表示，以SIG开头，比如SIGCHLD( 子进程结束向父进程发送的一个信号 )、SIGINT（Ctrl+c）等，它们在系统头文件<signal.h>中定义,也可以通过在shell下键入kill –l查看信号列表，或者键入man 7 signal查看更详细的说明。
      信号是系统响应某些条件而产生的一个事件，接收到该信的进程做出相应的处理。通常信是由错误产生的，如段错误(SIGSEGV)。 但信还可以作为进程间通信的一种方式，由一个进程发送给另一个进程。

另外有种更便捷友好地操作方式，这里用的是centos7，可以使用systemctl

[root@izj6c0ct64t9oyhoeow593z php7.3.10]# vim /usr/lib/systemd/system/php-fpm.service
Description=php-fpm
After=syslog.target network.target
[Service]
Type=forking
PIDFile=/usr/local/php7.3.10/var/run/php-fpm.pid
ExecStart=/usr/local/php7.3.10/sbin/php-fpm
ExecReload=/bin/kill -SIGUSR2 MAINPID
ExecStop=/bin/kill −SIGINT MAINPID
PrivateTmp=true
[Install]
WantedBy=multi-user.target
##让服务可用配置
[root@izj6c0ct64t9oyhoeow593z php7.3.10]# systemctl enable php-fpm
Created symlink from /etc/systemd/system/multi-user.target.wants/php-fpm.service to /usr/lib/systemd/system/php-fpm.service.
##重载system服务配置，使新增的php-pfm配置生效
[root@izj6c0ct64t9oyhoeow593z php7.3.10]# systemctl daemon-reload
##重启fpm报错
[root@izj6c0ct64t9oyhoeow593z php7.3.10]# systemctl reload php-fpm
Job for php-fpm.service invalid.
##查看错误原因,php-fpm还没启动
[root@izj6c0ct64t9oyhoeow593z php7.3.10]# systemctl status php-fpm
● php-fpm.service - php-fpm
Loaded: loaded (/usr/lib/systemd/system/php-fpm.service; disabled; vendor preset: disabled)
Active: inactive (dead)
10月 07 10:32:02 izj6c0ct64t9oyhoeow593z systemd[1]: Unit php-fpm.service cannot be reloaded because it is inactive.
##启动，没有提示(一般linux下没有输出就是正常的，就是好消息)
[root@izj6c0ct64t9oyhoeow593z php7.3.10]# systemctl start php-fpm
[root@izj6c0ct64t9oyhoeow593z php7.3.10]#

信号定义在/usr/include/asm/signal.h文件中，以 SIG 作为开头，也可用 kill -l 命令查看，详细信息参见 man 7 signal。

[root@izj6c0ct64t9oyhoeow593z php7.3.10]# kill -l
 ) SIGHUP     ) SIGINT     ) SIGQUIT     ) SIGILL     ) SIGTRAP
 ) SIGABRT     ) SIGBUS     ) SIGFPE     ) SIGKILL    ) SIGUSR1
) SIGSEGV    ) SIGUSR2    ) SIGPIPE    ) SIGALRM    ) SIGTERM
) SIGSTKFLT    ) SIGCHLD    ) SIGCONT    ) SIGSTOP    ) SIGTSTP
) SIGTTIN    ) SIGTTOU    ) SIGURG    ) SIGXCPU    ) SIGXFSZ
) SIGVTALRM    ) SIGPROF    ) SIGWINCH    ) SIGIO    ) SIGPWR
) SIGSYS    ) SIGRTMIN    ) SIGRTMIN+    ) SIGRTMIN+    ) SIGRTMIN+
) SIGRTMIN+    ) SIGRTMIN+    ) SIGRTMIN+    ) SIGRTMIN+    ) SIGRTMIN+
) SIGRTMIN+    ) SIGRTMIN+    ) SIGRTMIN+    ) SIGRTMIN+    ) SIGRTMIN+
) SIGRTMIN+    ) SIGRTMIN+    ) SIGRTMAX-    ) SIGRTMAX-    ) SIGRTMAX-
) SIGRTMAX-    ) SIGRTMAX-    ) SIGRTMAX-    ) SIGRTMAX-    ) SIGRTMAX-
) SIGRTMAX-    ) SIGRTMAX-    ) SIGRTMAX-    ) SIGRTMAX-    ) SIGRTMAX-
) SIGRTMAX-    ) SIGRTMAX
[root@izj6c0ct64t9oyhoeow593z php7.3.10]# cat /usr/include/asm/signal.h
#ifndef _ASM_X86_SIGNAL_H
#define _ASM_X86_SIGNAL_H

#ifndef __ASSEMBLY__
#include <linux/types.h>
#include <linux/time.h>

/* Avoid too many header ordering problems.  */
struct siginfo;

/* Here we must cater to libcs that poke about in kernel headers.  */

#define NSIG        32
typedef unsigned long sigset_t;

#endif /* __ASSEMBLY__ */

#define SIGHUP         1
#define SIGINT         2
#define SIGQUIT         3
#define SIGILL         4
#define SIGTRAP         5
#define SIGABRT         6
#define SIGIOT         6
#define SIGBUS         7
#define SIGFPE         8
#define SIGKILL         9
#define SIGUSR1        10
#define SIGSEGV        11
#define SIGUSR2        12
#define SIGPIPE        13
#define SIGALRM        14
#define SIGTERM        15
#define SIGSTKFLT    16
#define SIGCHLD        17
#define SIGCONT        18
#define SIGSTOP        19
#define SIGTSTP        20
#define SIGTTIN        21
#define SIGTTOU        22
#define SIGURG        23
#define SIGXCPU        24
#define SIGXFSZ        25
#define SIGVTALRM    26
#define SIGPROF        27
#define SIGWINCH    28
#define SIGIO        29
#define SIGPOLL        SIGIO
/*
#define SIGLOST        29
*/
#define SIGPWR        30
#define SIGSYS        31
#define    SIGUNUSED    31

/* These should not be considered constants from userland.  */
#define SIGRTMIN    32
#define SIGRTMAX    _NSIG

/*
 * SA_FLAGS values:
 *
 * SA_ONSTACK indicates that a registered stack_t will be used.
 * SA_RESTART flag to get restarting signals (which were the default long ago)
 * SA_NOCLDSTOP flag to turn off SIGCHLD when children stop.
 * SA_RESETHAND clears the handler when the signal is delivered.
 * SA_NOCLDWAIT flag on SIGCHLD to inhibit zombies.
 * SA_NODEFER prevents the current signal from being masked in the handler.
 *
 * SA_ONESHOT and SA_NOMASK are the historical Linux names for the Single
 * Unix names RESETHAND and NODEFER respectively.
 */
#define SA_NOCLDSTOP    0x00000001u
#define SA_NOCLDWAIT    0x00000002u
#define SA_SIGINFO    0x00000004u
#define SA_ONSTACK    0x08000000u
#define SA_RESTART    0x10000000u
#define SA_NODEFER    0x40000000u
#define SA_RESETHAND    0x80000000u

#define SA_NOMASK    SA_NODEFER
#define SA_ONESHOT    SA_RESETHAND

#define SA_RESTORER    0x04000000

#define MINSIGSTKSZ    2048
#define SIGSTKSZ    8192

#include <asm-generic/signal-defs.h>

#ifndef __ASSEMBLY__

/* Here we must cater to libcs that poke about in kernel headers.  */
#ifdef __i386__

struct sigaction {
    union {
      __sighandler_t _sa_handler;
      void (*_sa_sigaction)(int, struct siginfo *, void *);
    } _u;
    sigset_t sa_mask;
    unsigned long sa_flags;
    void (*sa_restorer)(void);
};

#define sa_handler    _u._sa_handler
#define sa_sigaction    _u._sa_sigaction

#else /* __i386__ */

struct sigaction {
    __sighandler_t sa_handler;
    unsigned long sa_flags;
    __sigrestore_t sa_restorer;
    sigset_t sa_mask;        /* mask last for extensibility */
};

#endif /* !__i386__ */

typedef struct sigaltstack {
    void *ss_sp;
    int ss_flags;
    size_t ss_size;
} stack_t;

#endif /* __ASSEMBLY__ */

#endif /* _ASM_X86_SIGNAL_H */