Nagios: NRPE: 无法读取输出，找不到原因，可以吗？

Question

我有一个 Nagios 服务器和一个受监控的服务器。在受监控的服务器上：

[root@Monitored ~]# netstat -an |grep :5666
tcp        0      0 0.0.0.0:5666                0.0.0.0:*                   LISTEN      
[root@Monitored ~]# locate check_kvm
/usr/lib64/nagios/plugins/check_kvm
[root@Monitored ~]# /usr/lib64/nagios/plugins/check_kvm -H localhost
hosts:3 OK:3 WARN:0 CRIT:0 - ab2c7:running alpweb5:running istaweb5:running
[root@Monitored ~]# /usr/lib64/nagios/plugins/check_nrpe -H localhost -c check_kvm
NRPE: Unable to read output
[root@Monitored ~]# /usr/lib64/nagios/plugins/check_nrpe -H localhost
NRPE v2.14
[root@Monitored ~]# ps -ef |grep nrpe
nagios   21178     1  0 16:11 ?        00:00:00 /usr/sbin/nrpe -c /etc/nagios/nrpe.cfg -d
[root@Monitored ~]#

在 Nagios 服务器上：

[root@Nagios ~]# /usr/lib64/nagios/plugins/check_nrpe -H 1.1.1.159 -c check_kvm
NRPE: Unable to read output
[root@Nagios ~]# /usr/lib64/nagios/plugins/check_nrpe -H 1.1.1.159
NRPE v2.14
[root@Nagios ~]#

当我使用相同的命令检查网络中的另一台服务器时，它可以工作：

[root@Nagios ~]# /usr/lib64/nagios/plugins/check_nrpe -H 1.1.1.80 -c check_kvm
hosts:4 OK:4 WARN:0 CRIT:0 - karmisoft:running ab2c4:running kidumim1:running travel2gether1:running
[root@Nagios ~]#

使用 Nagios 帐户在本地运行检查：

[root@Monitored ~]# su - nagios
-bash-4.1$ /usr/lib64/nagios/plugins/check_kvm
hosts:3 OK:3 WARN:0 CRIT:0 - ab2c7:running alpweb5:running istaweb5:running
-bash-4.1$

使用 Nagios 帐户从 Nagios 服务器远程运行检查：

-bash-4.1$ /usr/lib64/nagios/plugins/check_nrpe -H 1.1.1.159 -c check_kvm
NRPE: Unable to read output
-bash-4.1$ /usr/lib64/nagios/plugins/check_nrpe -H 1.1.1.159
NRPE v2.14
-bash-4.1$

使用 Nagios 帐户对网络中的不同服务器运行相同的 check_kvm：

-bash-4.1$ /usr/lib64/nagios/plugins/check_nrpe -H 1.1.1.80 -c check_kvm
hosts:4 OK:4 WARN:0 CRIT:0 - karmisoft:running ab2c4:running kidumim1:running travel2gether1:running
-bash-4.1$ 

权限：

-rwxr-xr-x. 1 root root 4684 2013-10-14 17:14 nrpe.cfg (aka /etc/nagios/nrpe.cfg)
drwxrwxr-x. 3 nagios nagios 4096 2013-10-15 03:38 plugins (aka /usr/lib64/nagios/plugins)

/etc/sudoers:

[root@Monitored ~]# grep -i requiretty /etc/sudoers
#Defaults    requiretty

iptables/selinux：

[root@Monitored xinetd.d]# service iptables status
iptables: Firewall is not running.
[root@Monitored xinetd.d]# service ip6tables status
ip6tables: Firewall is not running.
[root@Monitored xinetd.d]# grep disable /etc/selinux/config 
#     disabled - No SELinux policy is loaded.
SELINUX=disabled
[root@Monitored xinetd.d]#

里面的命令/etc/nagios/nrpe.cfg是：

[root@Monitored ~]# grep kvm /etc/nagios/nrpe.cfg 
command[check_kvm]=sudo /usr/lib64/nagios/plugins/check_kvm

并且nagios用户被添加到/etc/sudoers：

nagios  ALL=(ALL) NOPASSWD:/usr/lib64/nagios/plugins/check_kvm
nagios  ALL=(ALL) NOPASSWD:/usr/lib64/nagios/plugins/check_nrpe

这check_kvm是一个shell脚本，看起来像这样：

#!/bin/sh

LIST=$(virsh list --all | sed '1,2d' | sed '/^$/d'| awk '{print $2":"$3}')

if [ ! "$LIST" ]; then
  EXITVAL=3 #Status 3 = UNKNOWN (orange) 
  echo "Unknown guests"
  exit $EXITVAL
fi

OK=0
WARN=0
CRIT=0
NUM=0

for host in $(echo $LIST)
do
  name=$(echo $host | awk -F: '{print $1}')
  state=$(echo $host | awk -F: '{print $2}')
  NUM=$(expr $NUM + 1)

  case "$state" in
    running|blocked) OK=$(expr $OK + 1) ;;
    paused) WARN=$(expr $WARN + 1) ;;
    shutdown|shut*|crashed) CRIT=$(expr $CRIT + 1) ;;
    *) CRIT=$(expr $CRIT + 1) ;;
  esac
done

if [ "$NUM" -eq "$OK" ]; then
  EXITVAL=0 #Status 0 = OK (green)
fi

if [ "$WARN" -gt 0 ]; then
  EXITVAL=1 #Status 1 = WARNING (yellow)
fi

if [ "$CRIT" -gt 0 ]; then
  EXITVAL=2 #Status 2 = CRITICAL (red)
fi

echo hosts:$NUM OK:$OK WARN:$WARN CRIT:$CRIT - $LIST

exit $EXITVAL

编辑（2013 年 10 月 22 日）：在所有这些之后，我现在可以从脚本中得到一些响应：

[root@Monitored ~]# /usr/lib64/nagios/plugins/check_nrpe -H localhost -c check_kvm
Unknown guests
[root@Monitored ~]# /usr/lib64/nagios/plugins/check_nrpe -H localhost
NRPE v2.14
[root@Monitored ~]# /usr/lib64/nagios/plugins/check_kvm
hosts:3 OK:3 WARN:0 CRIT:0 - ab2c7:running alpweb5:running istaweb5:running
[root@Monitored ~]# su - nagios
-bash-4.1$ /usr/lib64/nagios/plugins/check_kvm
hosts:3 OK:3 WARN:0 CRIT:0 - ab2c7:running alpweb5:running istaweb5:running
-bash-4.1$ /usr/lib64/nagios/plugins/check_nrpe -H localhost -c check_kvm
Unknown guests
-bash-4.1$ /usr/lib64/nagios/plugins/check_nrpe -H localhost
NRPE v2.14

问题似乎与check_nrpe命令或与nrpe服务器上的安装有关的某些内容有关。

编辑 12/2/13：对有问题的服务器的其他检查工作：

Answer 1

伊泰写得好详细！您是否尝试过降低配置的复杂性来看看它是否有效？

对于初学者来说，我首先将行更改nrpe.cfg为

command[check_kvm]=/usr/lib64/nagios/plugins/check_kvm

并暂时将 /usr/lib64/nagios/plugins/check_kvm 脚本更改为非常简单的内容，例如：

#!/bin/sh
echo Hi
exit 0

如果有效，那么您就可以开始提高复杂性。也许它确实需要访问命令，而不是授予nagios用户 sudo 对脚本的访问权限，并且您可以在命令行中virsh省略该部分。sudonrpe.cfg