Perl开发自定义Nagios监视内存插件（nrpe端使用）

功能说明：脚本已经用在实践环境中，放到nrpe远程被监控端，用来实时监控远程主机内存。

监控内容包括：

free剩余大小；

总内存大小；

free剩余内存所占的百分比；

开发语言：perl

使用说明：提供三个参数，第一个是Memory表示针对内存进行监控，以后还提供对swap等其他的参数；第二个参数表示warning的阀值，20表示剩余内存小于等于20%时警告；第三个参数表示critical的阀值，10表示剩余内存不足10%时报警。举例如下：

# ./lionel_memory.pl Memory 20 10
Memory CRITICAL: FreeMem is 152488 KB,TotalMem is 3107192 KB,FreeMem% is 4% KB

其他细节：本脚本提供检测参数的功能，参数给出错误会提示Usage，warning的参数值一定要比critical的值大因为剩余内存越小警报级别才越高。最后，对剩余内存的算法我不是简单的使用free命令获取，而是收集的/proc/meminfo的值，并且考虑了Buffers与Cached两个值，反映真实的内存使用情况。还有，swap空间的使用并不代表物理内存完全耗尽，一般使用swap空间时物理内存还会剩余100多M的空间，但百分比肯定都不足10%了。

脚本内容如下，供大家参考：

脚本名称是【lionel_memory.pl 】
#!/usr/bin/perl
# author:shenxiaoran

use strict;

use lib "/opt/nrpe/libexec";
use utils qw(%ERRORS &print_revision &support &usage );

my ($opt_w,$opt_c) = ($ARGV[1],$ARGV[2]);
my $free_memory;
my $memfree;
my $buffers;
my $cached;
my $total_memory;
my $rate_free_memory;

if ( !defined $ARGV[0] or !defined $ARGV[1] or !defined $ARGV[2] ) {
??????? print "Usage: $0 {Memory} -w num -c num n";
??????? print "Example: lionel_memory.pl Memory 20 10 n";
}
else {
??????? free_memory($ARGV[0]);

}

sub free_memory() {
# MemTotal|MemFree|Buffers|Cached|SwapCached|Active|Inactive|SwapTotal|SwapFree
??????? if ( $opt_w < $opt_c ) {
??????????????? print "Error: -w num > -c num n";
??????????????? print "Usage: $0 {Memory} -w num -c num n";
??????????????? print "Example: lionel_memory.pl Memory 20 10 n";
??????????????? exit;
??????? }
??????? if ( $_[0] eq "Memory" ) {
??????????????? open(PROCESS,"cat /proc/meminfo|");
??????????????? ????foreach (<PROCESS>) {
??????????????? ????????if ($_ =~ /(MemFree.*s)(.*[0-9])( kB)/) {
??????????????? ????????????$memfree = $2;
??????????????? ????????}
??????????????? ????????if ($_ =~ /(Buffers.*s)(.*[0-9])( kB)/) {
??????????????? ????????????$buffers = $2;
??????????????????????? }
??????????????????????? if ($_ =~ /(^Cached.*s)(.*[0-9])( kB)/) {
??????????????????????? ????$cached = $2;
??????????????????????? }
??????????????????????? if ($_ =~ /(MemTotal.*s)(.*[0-9])( kB)/) {
??????????????????????????? $total_memory = $2;
??????????????? ????????}
??????????????????? }
?????????????? ???? $free_memory = $memfree + $buffers + $cached;
??????????????? ????$rate_free_memory = int($free_memory / $total_memory * 100);
??????????????? close(PROCESS);

??????????????? my $status = 'OK';
??????????????? if ( $rate_free_memory < $opt_c ) {
??????????????? $status = 'CRITICAL';
??????????????? }
??????????????? elsif ( $rate_free_memory < $opt_w ) {
??????????????? $status = 'WARNING';
??????????????? }
??????????????? print "$ARGV[0] $status: FreeMem is $free_memory KB,TotalMem is $total_memory KB,FreeMem% is ";
??????????????? printf "%0.0f%% KBn","$rate_free_memory";
??????????????? exit $ERRORS{$status};
??????? }
??????? else {
??????? print "Usage: $0 {Memory} -w num -c num n";
??????????????? print "Example: lionel_memory.pl Memory 20 10 n";
??????? }
}

脚本结束

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