Monitorggio di record MX con Nagios

• Il plugin utilizzato è il seguente:

sudo mkdir -p /usr/local/lib/nagios/plugins/

cat  | sudo tee /usr/local/lib/nagios/plugins/check_mx  > /dev/null <<'EOFile'
#!/usr/bin/env python

###############################################################################
# Nagios plugin to check if an host is configured as mx record for a domain
#
# Notes
# - You need dnspython installed:
#   sudo apt-get install python-dnspython
#
###############################################################################

__author__ = 'Gabriele Vivinetto'
__version__= 0.1

from optparse import OptionParser, OptionGroup
import logging as log

## These will override any args passed to the script normally. 
## Comment out after testing.
#testargs = '--help'
#testargs = '--version'
#testargs = '-vvv'

def main():
	""" Main plugin logic goes here """

	## Parse command-line arguments
	args, args2 = parse_args()

	## Options variable are accessibles as args.variablename

	## Uncomment to test logging levels against verbosity settings
	# log.debug('debug message')
	# log.info('info message')
	# log.warning('warning message')
	# log.error('error message')
	# log.critical('critical message')
	# log.fatal('fatal message')

	import dns.resolver

	# The domain name to check
	domain = args.domain
	
	log.info("Testing domain: " + domain )

	myResolver = dns.resolver.Resolver()

	## Find The ip address to check from args.hostIp and put into hostIp
	## Maybe the hostname resolves to multiple IPs
	
	try:
		hostIpAddresses = dns.resolver.query(args.hostIp,'A')
	except dns.resolver.NXDOMAIN:
		gtfo(3,"UNKNOWN No such hostname %s" % args.hostIp)
	except dns.resolver.Timeout:
		gtfo(3,"UNKNOWN Timed out while resolving %s" % args.hostIp)
	except dns.exception.DNSException:
		gtfo(3, "UNKNOWN Unknown error")

	## Find all the MX Records
	try:
		mxRecords = myResolver.query(domain, 'MX')
	except dns.resolver.NXDOMAIN:
		gtfo(3,"UNKNOWN No such domain %s" % domain)
	except dns.resolver.Timeout:
		gtfo(3,"UNKNOWN Timed out while resolving %s" % domain)
	except dns.exception.DNSException:
		gtfo(3, "UNKNOWN Unknown error")

	for ip in hostIpAddresses :
		hostIp = ip.to_text()

		log.info("Testing HOST IP " + hostIp )

		for record in mxRecords :
			mx = record.exchange.to_text()
			log.info("Testing MX " + mx )
			try:
				ipAddress = dns.resolver.query(mx,'A')
			except dns.resolver.NXDOMAIN:
				gtfo(3,"UNKNOWN No such domain %s" % mx)
			except dns.resolver.Timeout:
				gtfo(3,"UNKNOWN Timed out while resolving %s" % mx)
			except dns.exception.DNSException:
				gtfo(3, "UNKNOWN Unknown error")

			for ip in ipAddress :
				indirizzo = ip.to_text()
				if hostIp == indirizzo:
					log.info( hostIp + "=" + indirizzo)
					gtfo(0,"OK Your host " + args.hostIp + " with ip " + indirizzo + " is MX for domain " + domain)
		
		gtfo(2,"CRITICAL Your host " + hostIp + " is NOT an MX record for domain " + domain)
				

def parse_args():
	""" Parse command-line arguments """

	parser = OptionParser(usage='usage: %prog [-v|vv|vvv] [options]',
						  version='{0}: v.{1} by {2}'.format('%prog', __version__, __author__))

	## Verbosity (want this first, so it's right after --help and --version)
	parser.add_option('-v', help='Set verbosity level',
					  action='count', default=0, dest='v')

	## CLI arguments specific to this script
	#group = OptionGroup(parser,'Plugin Options')
	#group.add_option('-x', '--extra', help='Your option here',
	#				 default=None)
	#parser.add_option_group(group)
	
	parser.add_option('-H', '--hostname', help='The hostname/ip to check if its mx record',
					  dest='hostIp', metavar='##')

	parser.add_option('-d', '--domain', help='The domain name to check mx records for.',
					  dest='domain', metavar='##')

	## Common CLI arguments
	#parser.add_option('-c', '--critical', help='Set the critical threshold. Default: %(default)s',
	#				  default=97, type=float, dest='crit', metavar='##')
	#parser.add_option('-w', '--warning', help='Set the warning threshold. Default: %(default)s',
	#				  default=95, type=float, dest='warn', metavar='##')
	

	## Try to parse based on the testargs variable. If it doesn't exist, use args
	try:
		args, args2 = parser.parse_args(testargs.split())
	except NameError:
		args, args2 = parser.parse_args()

	## Set the logging level based on the -v arg
	log.getLogger().setLevel([log.ERROR, log.WARN, log.INFO, log.DEBUG][args.v])

	log.debug('Parsed arguments: {0}'.format(args))
	log.debug('Other  arguments: {0}'.format(args2))

	return args, args2

def gtfo(exitcode, message=''):
	""" Exit gracefully with exitcode and (optional) message """

	log.debug('Exiting with status {0}. Message: {1}'.format(exitcode, message))
	
	if message:
		print(message)
	exit(exitcode)

if __name__ == '__main__':
	## Initialize logging before hitting main, in case we need extra debuggability
	log.basicConfig(level=log.DEBUG, format='%(asctime)s - %(funcName)s - %(levelname)s - %(message)s')
	main()

EOFile

sudo chmod +x /usr/local/lib/nagios/plugins/check_mx

• Definire i check commands:

 # check-mx
define command{
    command_name    check-mx
    command_line    /usr/local/lib/nagios/plugins/check_mx -H $HOSTNAME$ -d $ARG1$
}

# check-mx-host
define command{
    command_name    check-mx-host
    command_line    /usr/local/lib/nagios/plugins/check_mx -H $ARG1$ -d $ARG2$
}

• Per testare se l'host oggetto del check è un record mx per il dominio example.com:

define service{
   use                 generic-service
   host_name           server.example.com
   service_description MX-EXAMPLED.COM
   check_command       check-mx!example.com
}

• Per testare se un host specifico otherserver.example.com è un record mx per il dominio example.com:

define service{
   use                 generic-service
   host_name           server.example.com
   service_description MX-EXAMPLE.COM
   check_command       check-mx!otherserver.example.com!exampledomain.com
}