monit

A general-purpose monit module for Puppet. Support for M/Monit is available but not tested on recent platforms.

Module usage

The simplest way to use this module:

class { '::monit':
  email => 'monitoring@example.org',
}

The email parameter can be omitted if global variable $::servermonitor is defined.

By default monit monitors CPU usage, load averages and memory, plus disk space and inode consumption on the root filesystem. The pre-configured thresholds can be customized as needed.

This module also includes additional defines:

• ::monit::filesystem: monitor space and inode usage of a filesystem
• ::monit::directory: monitor space and inode usage of a directory
• ::monit::writecheck: check if a path is writeable

Both ::monit::filesystem and ::monit::directory support parameter called $exec_cmd, which can be used to run a command if the check fails. A fairly typical use-case is cleaning up unused kernels in Ubuntu:

::monit::filesystem { 'boot-filesystem':
  path     => '/boot',
  exec_cmd => 'apt-get -y autoremove',
}

For this particular use-case, though, there's a sepate convenience class:

include ::monit::boot

The class runs a platform-specific autoremove task.

This module also supports creating monit fragments from other Puppet modules:

• ::monit::fragment

Any virtual ::monit::fragment resource tagged with 'default' is realized in the main ::monit class. The postfix module uses this feature:

• postfix/manifests/monit.pp
• postfix/templates/postfix.monit.erb

Also, if a File resource is tagged with 'monit' it will be realized as well; the use-case for this is adding test scripts for monit from other modules.

It is also possible to reuse a single template from several places, passing variables to it as a hash. For example:

class myclass::daemon1 {

  $vars = { 'service_name'  => $::myclass::params::daemon1_service_name,
            'pidfile'       => $::myclass::params::daemon1_pidfile,
            'service_start' => $::myclass::params::daemon1_service_start,
            'service_stop'  => $::myclass::params::daemon1_service_stop, }

  ::monit::fragment { 'daemon1.monit':
    ensure     => 'present',
    basename   => 'myservice',
    modulename => 'myclass',
    identifier => 'daemon1',
    vars       => $vars,
    epp        => true,
  }

In this case you'd have an EPP template in myclass/templates/myservice.monit.epp that uses the parameters along these lines:

### THIS FILE IS MANAGED BY PUPPET. ANY MANUAL CHANGES WILL GET OVERWRITTEN.

check process <%= $service_name %> with pidfile <%= $pidfile %>
    start program = "<%= $service_start %>"
    stop  program = "<%= $service_stop %>"
    alert <%= $::monit::email %> with reminder on 480 cycles

You could then pass the ::monit::fragment a different set of variables to make it configure some other service.