bin/check-zookeeper-file-descriptors.rb
#!/usr/bin/env ruby
#
# check-zookeeper-file-descriptors.rb
#
# DESCRIPTION:
# Check if Zookeeper has normal opened file descriptors rate.
#
# 'mntr' is a ZooKeeper four letter word command, which outputs
# a list of variables that could be used for monitoring
# the health of the cluster.
#
# Specifically file-descriptors.rb tests if the server has normal amount of opened file descriptors.
# Opened file descriptors rate is defined as (AVG_amount / MAX_amount).
#
# PLATFORMS:
# All
#
# DEPENDENCIES:
# gem: sensu-plugin
#
# USAGE:
# Check if a node has Zookeeper running and responds with imok.
# ./check-zookeeeper-file-descriptors.rb.rb # Equivalent to examples below
# ./check-zookeeeper-file-descriptors.rb.rb -s localhost -p 2181 -d 0.85
# ./check-zookeeeper-file-descriptors.rb.rb --server localhost --port 2181 --file-descriptors 0.85
#
# LICENCE:
# Phil Grayson <phil@philgrayson.com>
# Released under the same terms as Sensu (the MIT license); see LICENSE
# for details.
#
require 'sensu-plugin/check/cli'
require 'socket'
class CheckZookeeperREQS < Sensu::Plugin::Check::CLI
option :server,
description: 'Zookeeper hostname to connect to.',
short: '-s HOSTNAME',
long: '--server HOSTNAME',
default: 'localhost'
option :port,
description: 'Zookeeper port to connect to.',
short: '-p PORT',
long: '--port PORT',
default: 2181
option :timeout,
description: 'How long to wait for a reply in seconds.',
short: '-t SECS',
long: '--timeout SECS',
proc: proc(&:to_i),
default: 5
option :fd_critical,
description: 'Critical threshold for Zookeeper open files descriptors',
short: '-d DESCRIPTORS',
long: '--file-descriptors DESCRIPTORS',
proc: proc(&:to_f),
default: 0.85
def run
TCPSocket.open(config[:server], config[:port]) do |socket|
socket.write 'mntr'
ready = IO.select([socket], nil, nil, config[:timeout])
if ready.nil?
critical %(Zookeeper did not respond to 'mntr' within #{config[:timeout]} seconds)
end
result = ready.first.first.read.chomp.split("\n")
avg_fd = (result.grep(/zk_open_file_descriptor_count/)[0].split("\t")[1].to_f / result.grep(/zk_max_file_descriptor_count/)[0].split("\t")[1].to_f)
ok %(Zookeeper's open file descriptors rate is #{avg_fd}) if avg_fd < config[:fd_critical]
critical %(Zookeeper's open file descriptors rate is #{avg_fd}, which is more than #{config[:fd_critical]} threshold)
end
end
end