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 */