joemiller

# yum -y install rubygem-sensu
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
 * base: mirrors.sonic.net
 * epel: mirrors.solfo.com
 * extras: mirror.raystedman.net
 * updates: centos.mirrors.hoobly.com
sensu                                                                                | 1.2 kB     00:00     
sensu/primary                                                                        | 1.0 kB     00:00     
sensu                                                                                                   1/1

joemiller

$ rpm2cpio sensu-release.noarch.rpm |cpio --list
./etc/yum.repos.d
./etc/yum.repos.d/.bash_history
./etc/yum.repos.d/.bash_logout
./etc/yum.repos.d/.bash_profile
./etc/yum.repos.d/.bashrc
./etc/yum.repos.d/.cshrc
./etc/yum.repos.d/.gem
./etc/yum.repos.d/.gem/specs
./etc/yum.repos.d/.gem/specs/rubygems.org%80

joemiller

$ cat test.txt
blah 100
foo 20


$ cat test.rb
File.read('test.txt').each do |line|
    line =~ /^(\w+)\s+(\d+).*$/
    puts $1 + $2
end

joemiller

## 'update-static-leases on;' tells dhcpd to send ddns updates even for
## hosts that have 'fixed-addresses'. 
update-static-leases on;

joemiller

# the following logic is used when deciding what hostname to register in DNS
# when a client is assigned an addres.  The logic below says:
#       1. if the client sent a host-name as part of the DHCPREQUEST, use it
#       2. else, if the client is part of a fixed declaration, such as: "host <name> { .. }",
#               use <name> as the client's hostname
#       3. default scenario:  we can't figure anything out, so lets use the MAC address for the
#               hostname
if exists host-name {
        option server.ddns-hostname = option host-name;
} elsif known {

joemiller

#lease-file-name "/usr/local/dhcpd/var/dhcpd.leases";

#pid-file-name "/usr/local/dhcpd/var/dhcpd.pid";
#ping-check false;

option ntp-servers 10.0.0.1;

option domain-name "dom.tld";
option domain-name-servers 10.0.0.1;

joemiller

In my previous article I mentioned a key strength of Sensu is the ability to re-use existing Nagios plugins. This is a powerful feature of Sensu. Nagios has been around for at least 1000 years according to most recent archaeological discoveries, which means a vast amount of human effort (and capital) has gone into creating Nagios plugins. Being able to leverage this prior effort is a huge win. In this article I'll demonstrate creating a Sensu check with the check_http Nagios plugin.

Install the check_http nagios plugin

Following on the previous article, we'll be doing this demo based off of CentOS 5 but it should not be difficult to find a build of check_http for your distribution.

First, Make sure you have the EPEL yum repo installed on your machine. Next, let'

joemiller

$ echo "yo dog, i heard you like some cats with your queues so i catted your queues" | ./catamqp.rb 
$ ./amqpcat.rb 
yo dog, i heard you like some cats with your queues so i catted your queues

joemiller

"handlers": { 
  "default": { "type": "pipe", "command": "/etc/sensu/handlers/default" },
},

joemiller

{
  "checks": {
    "test": {
      "handler": "default",
      "command": "echo 'Im OK'; exit 0",
      "standalone": true,
      "interval": 60
    }
  }  
}