check_ipvs.py

#!/usr/bin/env python3

import argparse
import sys
import re
import os

__author__ = 'Dmytro Prokhorenkov'
__version__ = 1.0


def parse_ipvs_output(res):
    output = {}
    pattern_vs = '(\w+)\s+([0-9.]+):(\w+)\s+(\w+)'
    pattern_node = '\s->\s([0-9.]+):(\w+)\s+(\w+)\s+(\d+)\s+(\d+)\s+(\d+)'
    cp_vs = re.compile(pattern_vs)
    cp_node = re.compile(pattern_node)
    current_vs = ''
    for line in res.split('\n'):
        if line[:3] == 'TCP' or line[:3] == 'UDP':
            current_vs = line
            result = cp_vs.split(line)
            output = {
                'type': result[1],
                'vip': result[2],
                'vport': result[3],
                'scheduler': result[4],
                'nodes': []
            }
        elif line[2:4] == '->':
            result = cp_node.split(line)
            if len(result) > 1:
                output['nodes'].append({'nip': result[1], 'nport': result[2], 'fwd': result[3],
                                        'weight': result[4], 'active': result[5], 'inactive': result[6]})
    return output


def text_is_ip(txt):
    if re.match("^((25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$", txt):
        return True
    else:
        return False


sudo = ""
protocol_list = {
    'tcp': '-t',
    'udp': '-u'
}

parent_parser = argparse.ArgumentParser(add_help=True, description='Check for ldirectord/ipvs',
                                        epilog='{0}: v.{1} by {2}'.format('check_oom.py', __version__, __author__))
parent_parser.add_argument(
    '--proto', type=str, help="Set protocol for service (tcp, udp)", default="tcp")
parent_parser.add_argument(
    '--service', type=str, help="Specify service name (It should be specified like <ip_address>:<port>)")
parent_parser.add_argument(
    '--sudo', help="Use SUDO to get information", action="store_true")
_args = vars(parent_parser.parse_args())

# Check if specified protocol type is correct
if _args['proto'] not in protocol_list:
    print("ERROR: Wrong protocol type is specified\n")
    parent_parser.print_help()
    sys.exit(3)

# Check if service is specified
if (_args['service'] == None):
    parent_parser.print_help()
    sys.exit(3)

# Check if service address is correct ip address and port is not out of range
ip_info = re.split(":", _args['service'])
if not(text_is_ip(ip_info[0])):
    print("ERROR: You specified wrong ip\n")
    parent_parser.print_help()
    sys.exit(3)
try:
    port = int(ip_info[1])
except ValueError:
    print("ERROR: You specified not numeric port\n")
    parent_parser.print_help()
    sys.exit(3)
if not(1 <= port <= 65535):
    print("ERROR: You specified wrong port\n")
    parent_parser.print_help()
    sys.exit(3)

# Check if sudo is enabled
if _args['sudo']:
    sudo = "sudo "

cmd = sudo + "/sbin/ipvsadm -L -n " + \
    protocol_list[_args['proto']] + " " + _args['service']
result = os.popen(cmd).read()

ipvs = parse_ipvs_output(result)

issues = []

for node in ipvs['nodes']:
    if int(node['weight']) == 0:
        txt = 'Node ' + node['nip'] + ':' + node['nport'] + \
            ' is unreachable by load balancer. '
        issues.append(txt)

nagios_output = ""

if issues != []:
    nagios_output = "CRITICAL: We have next issues:\n"
    for issue in issues:
        nagios_output = nagios_output + issue + "\n"
    print(nagios_output)
    sys.exit(2)
else:
    nagios_output = "OK: Service " + ipvs['vip'] + ":" + ipvs['vport'] + \
        " work as expected. " + str(len(ipvs['nodes'])) + " are available."
    print(nagios_output)
    sys.exit(0)