php Implementation of master worker Daemon Multi process Mode Instance Code

The specific code is as follows:

<?php
class Worker{
  public static $count = 2;
  public static function runAll(){
    static::runMaster();
    static::moniProcess();
  }
  // Start the main process 
  public static function runMaster(){
    // Ensure that the process has maximum operation permissions 
    unmask(0);
    $pid = pcntl_fork();
    if($pid > 0){
      echo " Main process process  $pid \n";
      exit;  
    }else if($pid == 0){
      if(-1 === posix_setsid()){
          throw new Exception("setsid fail");
      }
      for ($i=0; $i < self::$count; $i++) {
        static::runWorker();
      }
      @cli_set_process_title("master_process");
    }else{
      throw new Exception(" Failed to create main process ");
    }
  } 
  // Start a child process 
  public static function runWorker(){
    unmask(0);
    $pid = pcntl_fork();
    if($pid > 0){
      // echo " Create a child process  $pid \n";
    }else if($pid == 0){
      if(-1 === posix_setsid()){
        throw new Exception("setsid fail");
      }
      @cli_set_process_title("worker_process");
      while(1){
        sleep(1);
      }
    }else{
      throw new Exception(" Failed to create child process ");
    }
  }
  // Monitoring worker Process 
  public function moniProcess(){
    while( $pid = pcntl_wait($status)){
      if($pid == -1){
        break;
      }else{
        static::runWorker();
      }
    }
  }
}
Worker::runAll();

ps -aux
USER    PID %CPU %MEM  VSZ  RSS TTY   STAT START  TIME COMMAND
root     1 0.0 0.0 18200 3076 pts/0  Ss+ 14:05  0:00 bash
root     6 0.0 0.0 18208 3252 pts/1  Ss  14:06  0:00 bash
root    19 0.0 0.0 18204 3248 pts/2  Ss+ 14:11  0:00 bash
root    64 0.0 0.2 348488 8320 ?    Ss  15:32  0:00 master_process
root    65 0.0 0.2 348488 8400 ?    Ss  15:32  0:00 worker_process
root    66 0.0 0.2 348488 8400 ?    Ss  15:32  0:00 worker_process
root    67 0.0 0.0 36640 2804 pts/1  R+  15:32  0:00 ps -aux

Execute the command kill 65, kill the process 65 and the master_process process will automatically start another child process

USER    PID %CPU %MEM  VSZ  RSS TTY   STAT START  TIME COMMAND
root     1 0.0 0.0 18200 3076 pts/0  Ss+ 14:05  0:00 bash
root     6 0.0 0.0 18208 3252 pts/1  Ss  14:06  0:00 bash
root    19 0.0 0.0 18204 3248 pts/2  Ss+ 14:11  0:00 bash
root    64 0.0 0.2 348488 8320 ?    Ss  15:32  0:00 master_process
root    66 0.0 0.2 348488 8400 ?    Ss  15:32  0:00 worker_process
root    68 0.0 0.1 348488 5796 ?    Ss  15:34  0:00 worker_process
root    69 0.0 0.0 36640 2728 pts/1  R+  15:34  0:00 ps -aux

Summarize