check_juniper_ex_virtchas_count.rb

README.md

Check count of members in a Juniper virtual chassis

check_juniper_ex_virtchas_count.rb

#!/usr/bin/ruby
######################################################################################################
#
# Description:
#  Query an Virtual Chassis and check how many switches exist in it
#
######################################################################################################
#
# Author: Nick Peelman (2017-02-15)
#
######################################################################################################
#
# Usage:
#  check_juniper_ex_virtchas_count.rb -H <hostname> -C <community> -c <expected_count>
#
#  Parameters:
#	* <hostname>: the hostname / IP Address of the virtual chassis
#	* <community>: the SNMP community string
# * <expected_count>: how many switches should be in the stack
#
######################################################################################################
#
# Requirements
# * gem install snmp
#
######################################################################################################


require 'snmp'
require 'optparse'

######################################################################################################

OID_CHASSIS_SERIALS =  "1.3.6.1.4.1.2636.3.40.1.4.1.1.1.2"

######################################################################################################

@hostname = nil
@community = nil
@expected_count = 0

def parse_args(args = {})
  @opts = OptionParser.new
  @opts.on('-H', "--host HOSTNAME", "Hostname of the Virtual Chassis") do |hostname|
    @hostname = hostname
  end
  @opts.on("-C", "--community COMMUNITY", "SNMP Community String") do |community|
    @community = community
  end
  @opts.on("-c", "--count COUNT", "The number of switches that should exist") do |count|
    @expected_count = count
  end
  @opts.on_tail("-h", "--help", "Show this message") do
    puts @opts
    exit
  end
  @opts.parse!
end

def members(host, community)
  members = []
  SNMP::Manager.open(host: host, community: community) do |manager|
    manager.walk([OID_CHASSIS_SERIALS]) { |var|
        members.push var.first.value
    }
  end
  return members
end

parse_args()

chassis = members(@hostname, @community)

case
when chassis.count == @expected_count
  puts "OK: Chassis Count is #{chassis.count}"
  exit 0
when chassis.count < @expected_count
  puts "CRITICAL: The chassis count (#{chassis.count}) is too low!"
  exit 2
when chassis.count > @expected_count
  puts "WARNING: The chassis count (#{chassis.count}) is too high!"
  exit 1
else
  puts "UNKNOWN: Could not determine chassis count (reporting: #{chassis.count})"
  exit 3
end

Do u have any information on how to monitor interfaces in the stack members..

I'd just use the standard monitoring_plugins interface monitor. As long as you're monitoring a shared IP interface, you'll be able to see the info for all interfaces in the stack.

If you're large enough to run a stack of these things though, and even if you just have > 1 of them, I highly suggest LibreNMS. Will give you a lot more than just up/down status.