Hello World

如果nagios 發現異常要發送警告信給管理者
本機必須要有postfix或sendmail 之類的MTA

如果因為資安考量或其他因素不打算安裝
或是跑在docker 上，預設也沒有MTA，就無法發送信件

幸好nagios 非常地有彈性
可以改觸發其他scripts

以下範例改用 phpmailer 發送

編輯 /phpmailer/example/mail.php
#!/usr/bin/php

<?php

/**
 * This example shows making an SMTP connection with authentication.
 */

//Import the PHPMailer class into the global namespace
use PHPMailer\PHPMailer\PHPMailer;
use PHPMailer\PHPMailer\SMTP;

//SMTP needs accurate times, and the PHP time zone MUST be set
//This should be done in your php.ini, but this is how to do it if you don't have access to that
date_default_timezone_set('Asia/Taipei');

require '/phpmailer/vendor/autoload.php';

$content = file ('php://stdin');
$text = implode ($content);
$html = nl2br($text);
$subject = $argv[1];
$mailto = $argv[2];

//Create a new PHPMailer instance
$mail = new PHPMailer();
//Tell PHPMailer to use SMTP
$mail->isSMTP();
//Enable SMTP debugging
//SMTP::DEBUG_OFF = off (for production use)
//SMTP::DEBUG_CLIENT = client messages
//SMTP::DEBUG_SERVER = client and server messages
$mail->SMTPDebug = SMTP::DEBUG_OFF;
//Set the hostname of the mail server
$mail->Host = 'SMTP伺服器';
//Set the SMTP port number - likely to be 25, 465 or 587
$mail->Port = 25;
//Whether to use SMTP authentication
$mail->SMTPAuth = true;
//Username to use for SMTP authentication
$mail->Username = '寄件者帳號';
//Password to use for SMTP authentication
$mail->Password = '寄件者密碼';
//Set who the message is to be sent from
$mail->setFrom('寄件者email', '寄件者顯示名稱');
//Set an alternative reply-to address
$mail->addReplyTo('寄件者email', '寄件者顯示名稱');
//Set who the message is to be sent to
$mail->addAddress($mailto, '收件者顯示名稱');
//Set the subject line
$mail->Subject = $subject;
//Read an HTML message body from an external file, convert referenced images to embedded,
//convert HTML into a basic plain-text alternative body
$mail->msgHTML($html, __DIR__);
//Replace the plain text body with one created manually
$mail->AltBody = $text;
//Attach an image file
//$mail->addAttachment('images/phpmailer_mini.png');

//send the message, check for errors
if (!$mail->send()) {
    echo 'Mailer Error: ' . $mail->ErrorInfo;
} else {
    echo 'Message sent!';
}

編輯
command.cfg
找到
/usr/bin/mail -s "** $NOTIFICATIONTYPE$ Host Alert: $HOSTNAME$ is $HOSTSTATE$ **" $CONTACTEMAIL$
修改成
/phpmailer/example/mail.php "** $NOTIFICATIONTYPE$ Host Alert: $HOSTNAME$ is $HOSTSTATE$ **" $CONTACTEMAIL$

重啟 nagios