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George Shammas

2012-Sep-24 16:47 UTC

[Puppet Users] Overriding variables.

I am trying to override variables in a class that is defined in the default 
node profile. I want parent class to be included in every single node, but 
override its variables in others. I have tried it several different ways 
now, and every single time the variables either become unset (undefined) or 
are set to the value of the first if statement.

Here is my current iteration of failure. warn_real is always equal 
to processorcount, no matter if I override it or not.

class nrpe::load ($warn = ''UNSET'', $crit =
''UNSET'') {

    package { nagios-plugins-load: ensure => installed }

    if $warn == ''UNSET'' {
        $warn_real = $processorcount
    }
    if $crit == ''UNSET'' {
        $crit_real = $processorcount * 2
    }

    file { "/etc/nagios/command.d/load.cfg":
        owner   => root,
        group   => root,
        mode    => 640,
        content => template("nrpe/load.cfg.erb"),
        notify => Service[nrpe]
    }
}


class nrpe::load::override($warn = ''UNSET'', $crit =
''UNSET'') inherits
nrpe::load {

    Class["nrpe::load"] {
        warn => $warn,
        crit => $crit
    }
}

node "somenode.tld" inherits basenode {
    class {''nrpe::load::override'':
        warn => 5,
        crit => 10
    }
}

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George Shammas

2012-Sep-24 20:48 UTC

head link

[Puppet Users] Re: Overriding variables.

Another iteration of failure is the following. This one is in the likeness 
of ::parms for a class, but if it nrpe:load inherits override class, then I 
can''t declare the override class anywhere else. This was my 
first attempt to do this, and have tried 4 other iterations of this, but as 
far as I can tell, because it can''t inherit the class, it will ONLY use
the
default values, which can only be undef or some other default value, again 
defeating the ability to override.

class nrpe::load {

    package { nagios-plugins-load: ensure => installed }

    if $nrpe::load::override::warn == ''UNSET'' {
        $warn = $processorcount
    } else {
        $warn = $nrpe::load::override::warn
    }
    if $nrpe::load::override::crit == ''UNSET'' {
        $crit = $processorcount * 2
    } else {
        $crit = $nrpe::load::override::crit
    }

    file { "/etc/nagios/command.d/load.cfg":
        owner   => root,
        group   => root,
        mode    => 640,
        content => template("nrpe/load.cfg.erb"),
        notify => Service[nrpe]
    }
}    


class nrpe::load::override($warn = ''UNSET'', $crit =
''UNSET'') {
}


On Monday, September 24, 2012 12:47:31 PM UTC-4, George Shammas
wrote:>
> I am trying to override variables in a class that is defined in the 
> default node profile. I want parent class to be included in every single 
> node, but override its variables in others. I have tried 
> it several different ways now, and every single time the variables either 
> become unset (undefined) or are set to the value of the first if statement.
>
> Here is my current iteration of failure. warn_real is always equal 
> to processorcount, no matter if I override it or not.
>
> class nrpe::load ($warn = ''UNSET'', $crit =
''UNSET'') {
>
>     package { nagios-plugins-load: ensure => installed }
>
>     if $warn == ''UNSET'' {
>         $warn_real = $processorcount
>     }
>     if $crit == ''UNSET'' {
>         $crit_real = $processorcount * 2
>     }
>
>     file { "/etc/nagios/command.d/load.cfg":
>         owner   => root,
>         group   => root,
>         mode    => 640,
>         content => template("nrpe/load.cfg.erb"),
>         notify => Service[nrpe]
>     }
> }
>
>
> class nrpe::load::override($warn = ''UNSET'', $crit =
''UNSET'') inherits
> nrpe::load {
>
>     Class["nrpe::load"] {
>         warn => $warn,
>         crit => $crit
>     }
> }
>
> node "somenode.tld" inherits basenode {
>     class {''nrpe::load::override'':
>         warn => 5,
>         crit => 10
>     }
> }
>
>
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jcbollinger

2012-Sep-25 15:28 UTC

head link

[Puppet Users] Re: Overriding variables.

On Monday, September 24, 2012 11:47:31 AM UTC-5, George Shammas
wrote:>
> I am trying to override variables in a class that is defined in the 
> default node profile. I want parent class to be included in every single 
> node, but override its variables in others. I have tried 
> it several different ways now, and every single time the variables either 
> become unset (undefined) or are set to the value of the first if statement.

You cannot override class variables.  You especially cannot override class 
parameters.  You can override only resource properties (and classes are not 
resources, appearances notwithstanding).

Moreover, subclasses do not set parameters for their parent classes, even 
if they themselves have parameters of the same names.  Therefore, it is 
usually a bad idea to inherit from a parametrized class (in fact, the v 2.7 
docs say it''s not supported).  If you do so, then you must explicitly 
declare the parent class on every node for which you want to set 
non-default parameters, whether or not you also declare the child class.

Since you don''t actually use the variables in question in your example,
I
can''t guess what your larger purpose may be, therefore it is difficult
for
me to advise you.  Nevertheless, at the low level we are focused on, you 
can achieve something similar to what you have asked by employing a data 
hierarchy instead of a class hierarchy.  That is what the Hiera module is 
all about.  Since hiera will be integrated into Puppet 3, getting started 
with it now is also forward-looking.

Once you install hiera and set up your data, the Puppet side could be as 
simple as this:

class nrpe::load { # no parameters
    package { ''nagios-plugins-load'': ensure => installed }

    $warn_real = hiera(''nrpe::warn'')
    $crit_real = hiera(''nrpe::crit'')

    # alternatively, load $warn and $crit via hiera,
    # and retain the original logic for setting
    # $warn_real and $crit_real

    file { "/etc/nagios/command.d/load.cfg":
        owner   => root,
        group   => root,
        mode    => 640,
        content => template("nrpe/load.cfg.erb"),
        notify => Service[nrpe]
    }
}

node "somenode.tld" inherits basenode {
  # no subclass involved
}

John

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George Shammas

2012-Sep-25 15:56 UTC

head link

[Puppet Users] Re: Overriding variables.

Hi John,

Thanks for the response. They variables are only used in the template, as 
the NRPE daemon is manged by flat files. I will do some research into hiera.

--George

On Tuesday, September 25, 2012 11:28:31 AM UTC-4, jcbollinger
wrote:>
>
>
> On Monday, September 24, 2012 11:47:31 AM UTC-5, George Shammas wrote:
>>
>> I am trying to override variables in a class that is defined in the 
>> default node profile. I want parent class to be included in every
single
>> node, but override its variables in others. I have tried 
>> it several different ways now, and every single time the variables
either
>> become unset (undefined) or are set to the value of the first if
statement.
>
>
> You cannot override class variables.  You especially cannot override class 
> parameters.  You can override only resource properties (and classes are not
> resources, appearances notwithstanding).
>
> Moreover, subclasses do not set parameters for their parent classes, even 
> if they themselves have parameters of the same names.  Therefore, it is 
> usually a bad idea to inherit from a parametrized class (in fact, the v 2.7
> docs say it''s not supported).  If you do so, then you must
explicitly
> declare the parent class on every node for which you want to set 
> non-default parameters, whether or not you also declare the child class.
>
> Since you don''t actually use the variables in question in your
example, I
> can''t guess what your larger purpose may be, therefore it is
difficult for
> me to advise you.  Nevertheless, at the low level we are focused on, you 
> can achieve something similar to what you have asked by employing a data 
> hierarchy instead of a class hierarchy.  That is what the Hiera module is 
> all about.  Since hiera will be integrated into Puppet 3, getting started 
> with it now is also forward-looking.
>
> Once you install hiera and set up your data, the Puppet side could be as 
> simple as this:
>
> class nrpe::load { # no parameters
>     package { ''nagios-plugins-load'': ensure =>
installed }
>
>     $warn_real = hiera(''nrpe::warn'')
>     $crit_real = hiera(''nrpe::crit'')
>
>     # alternatively, load $warn and $crit via hiera,
>     # and retain the original logic for setting
>     # $warn_real and $crit_real
>
>     file { "/etc/nagios/command.d/load.cfg":
>         owner   => root,
>         group   => root,
>         mode    => 640,
>         content => template("nrpe/load.cfg.erb"),
>         notify => Service[nrpe]
>     }
> }
>
> node "somenode.tld" inherits basenode {
>   # no subclass involved
> }
>
>
> John
>
>
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Lorenzo Salvadorini

2012-Sep-26 08:44 UTC

head link

Re: [Puppet Users] Re: Overriding variables.

I''ve solved the identical problem using defines instead of classes. I
know that hiera can be a better solution, but I''m waiting for next
major release to adopt hiera.

I''ve a generic nrpe::check define: each check is a define that use
this generic definition, so my check_load.pp in nrpe module is

define nrpe::check_load(
    $warn1=8,
    $warn5=4,
    $warn15=2,
    $crit1=20,
    $crit5=10,
    $crit15=5,
    )
  {
      if ! is_numeric($warn1)
      {
        fail(''Variable warn1 must be numeric'')
      }
      if ! is_numeric($warn5)
      {
        fail(''Variable warn5 must be numeric'')
      }
      if ! is_numeric($warn15)
      {
        fail(''Variable warn15 must be numeric'')
      }
      if ! is_numeric($crit1)
      {
        fail(''Variable crit1 must be numeric'')
      }
      if ! is_numeric($crit5)
      {
        fail(''Variable crit5 must be numeric'')
      }
      if ! is_numeric($crit15)
      {
        fail(''Variable crit15 must be numeric'')
      }

      # -r plugin option make it compatible with multi-core cpu
      nrpe::check{ ''load'':
         params  => "-r -w ${warn1},${warn5},${warn15} -c
${crit1},${crit5},${crit15}"
      }
  }



In generic_host I create a resource with no parameters, so defaults apply:

nrpe::check_load { ''load'': }


If I''ve a node with a medium greater load than my default I do:

node ''node-with-high-load'' inherits generic_host {
    Nrpe::Check_load[''load'']{ warn5 => 20 }
}


Hopes this helps,
L



2012/9/25 George Shammas <georgyo@gmail.com>:> Hi John,
>
> Thanks for the response. They variables are only used in the template, as
> the NRPE daemon is manged by flat files. I will do some research into
hiera.
>
> --George
>
> On Tuesday, September 25, 2012 11:28:31 AM UTC-4, jcbollinger wrote:
>>
>>
>>
>> On Monday, September 24, 2012 11:47:31 AM UTC-5, George Shammas wrote:
>>>
>>> I am trying to override variables in a class that is defined in the
>>> default node profile. I want parent class to be included in every
single
>>> node, but override its variables in others. I have tried it several
>>> different ways now, and every single time the variables either
become unset
>>> (undefined) or are set to the value of the first if statement.
>>
>>
>> You cannot override class variables.  You especially cannot override
class
>> parameters.  You can override only resource properties (and classes are
not
>> resources, appearances notwithstanding).
>>
>> Moreover, subclasses do not set parameters for their parent classes,
even
>> if they themselves have parameters of the same names.  Therefore, it is
>> usually a bad idea to inherit from a parametrized class (in fact, the v
2.7
>> docs say it''s not supported).  If you do so, then you must
explicitly
>> declare the parent class on every node for which you want to set
non-default
>> parameters, whether or not you also declare the child class.
>>
>> Since you don''t actually use the variables in question in your
example, I
>> can''t guess what your larger purpose may be, therefore it is
difficult for
>> me to advise you.  Nevertheless, at the low level we are focused on,
you can
>> achieve something similar to what you have asked by employing a data
>> hierarchy instead of a class hierarchy.  That is what the Hiera module
is
>> all about.  Since hiera will be integrated into Puppet 3, getting
started
>> with it now is also forward-looking.
>>
>> Once you install hiera and set up your data, the Puppet side could be
as
>> simple as this:
>>
>> class nrpe::load { # no parameters
>>     package { ''nagios-plugins-load'': ensure =>
installed }
>>
>>     $warn_real = hiera(''nrpe::warn'')
>>     $crit_real = hiera(''nrpe::crit'')
>>
>>     # alternatively, load $warn and $crit via hiera,
>>     # and retain the original logic for setting
>>     # $warn_real and $crit_real
>>
>>     file { "/etc/nagios/command.d/load.cfg":
>>         owner   => root,
>>         group   => root,
>>         mode    => 640,
>>         content => template("nrpe/load.cfg.erb"),
>>         notify => Service[nrpe]
>>     }
>> }
>>
>> node "somenode.tld" inherits basenode {
>>   # no subclass involved
>> }
>>
>>
>> John
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