Puppet users - Jun 2009 - Testing if a resource is already defined

Hi gang,

Is it possible to test if a particular resource has already been 
defined? I''d like to do something like this:

if !Host["$fqdn"] {
    host {"$fqdn": ip => "$ipaddress_eth0" }
}

Essentially, test to see if there is no Host resource defined for the 
current server and if not, add a host entry for itself using the IP 
address of eth0.

Possible?

Ta,
Avi

--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Puppet Users" group.
To post to this group, send email to puppet-users@googlegroups.com
To unsubscribe from this group, send email to
puppet-users+unsubscribe@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/puppet-users?hl=en
-~----------~----~----~----~------~----~------~--~---

Hi
> Is it possible to test if a particular resource has already been 
> defined? I''d like to do something like this:
> 
> if !Host["$fqdn"] {
>     host {"$fqdn": ip => "$ipaddress_eth0" }
> }
> 
> Essentially, test to see if there is no Host resource defined for the 
> current server and if not, add a host entry for itself using the IP 
> address of eth0.
http://reductivelabs.com/trac/puppet/wiki/FunctionReference#defined

cheers pete

--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Puppet Users" group.
To post to this group, send email to puppet-users@googlegroups.com
To unsubscribe from this group, send email to
puppet-users+unsubscribe@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/puppet-users?hl=en
-~----------~----~----~----~------~----~------~--~---

Hello,

On 18.06.2009, at 10:03, Peter Meier wrote:
>
> Hi
>
>> Is it possible to test if a particular resource has already been
>> defined? I''d like to do something like this:
>>
>> if !Host["$fqdn"] {
>>    host {"$fqdn": ip => "$ipaddress_eth0" }
>> }
>>
>> Essentially, test to see if there is no Host resource defined for the
>> current server and if not, add a host entry for itself using the IP
>> address of eth0.
>
> http://reductivelabs.com/trac/puppet/wiki/FunctionReference#defined
In principle, this should do. Unfortunately there''s this small catch  
that:

"This function is unfortunately dependent on the parse order of the  
configuration when testing whether a resource is defined."

I have many situations where i would like to test whether a class ist  
defined or not. This does not work for most situations.

Would it be possible to rewrite "defined" such that it is not  
dependent on the parse order of manifest?

As I understand puppet, this is not easily achievable. I am not sure,  
though.

All the best,
udo.
-- 
:: udo waechter - root@zoide.net :: N 52º16''30.5" E
8º3''10.1"
:: genuine input for your ears: http://auriculabovinari.de
::                          your eyes: http://ezag.zoide.net
::                          your brain: http://zoide.net

On Thu, Jun 18, 2009 at 12:14:59PM +1000, Avi Miller
wrote:
> 
> Hi gang,
> 
> Is it possible to test if a particular resource has already been 
> defined? I''d like to do something like this:
> 
> if !Host["$fqdn"] {
>     host {"$fqdn": ip => "$ipaddress_eth0" }
> }
> 
> Essentially, test to see if there is no Host resource defined for the 
> current server and if not, add a host entry for itself using the IP 
> address of eth0.
> 
> Possible?
It sounds like you might be trying to define a host in more than one place.
I''m just a journeryman myself, but I think according to The Puppet Way
(TM)
that''s a Bad Thing (TM).

If you make sure that the host is only potentially defined in one place, you
don''t have to worry about this.

Cheers,

-- 
Eric Gerlach, Network Administrator
Federation of Students
University of Waterloo
p: (519) 888-4567 x36329
e: egerlach@feds.uwaterloo.ca

--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Puppet Users" group.
To post to this group, send email to puppet-users@googlegroups.com
To unsubscribe from this group, send email to
puppet-users+unsubscribe@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/puppet-users?hl=en
-~----------~----~----~----~------~----~------~--~---

Eric Gerlach wrote:
> It sounds like you might be trying to define a host in more than one place.
> I''m just a journeryman myself, but I think according to The Puppet
Way (TM)
> that''s a Bad Thing (TM).
Yes, I am and yes, it is, but I don''t have (much) choice without making
our manifests rather larger and more cumbersome. Using the defined() 
function and replacing the host{} type with a custom add_host{} 
definition (that wraps the function) works just fine.

cYa,
Avi

--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Puppet Users" group.
To post to this group, send email to puppet-users@googlegroups.com
To unsubscribe from this group, send email to
puppet-users+unsubscribe@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/puppet-users?hl=en
-~----------~----~----~----~------~----~------~--~---

Avi Miller wrote:
> Eric Gerlach wrote:
>> It sounds like you might be trying to define a host in more than one
place.
>> I''m just a journeryman myself, but I think according to The
Puppet Way (TM)
>> that''s a Bad Thing (TM).
> 
> Yes, I am and yes, it is, but I don''t have (much) choice without
making
> our manifests rather larger and more cumbersome. Using the defined() 
> function and replacing the host{} type with a custom add_host{} 
> definition (that wraps the function) works just fine.
> 
Why don''t you just define it virtually and realize it at will?

-scott

-- 
scott@ohlol.net

http://github.com/ohlol

--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Puppet Users" group.
To post to this group, send email to puppet-users@googlegroups.com
To unsubscribe from this group, send email to
puppet-users+unsubscribe@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/puppet-users?hl=en
-~----------~----~----~----~------~----~------~--~---

On 20/06/2009, at 8:01 AM, Scott Smith <scott@ohlol.net> wrote:
> Why don''t you just define it virtually and realize it at will?
Because the value for the IP address changes depending on where it  
appears in the manifest. I''m working in an environment where each  
server has at least 2 and up to 6 addresses, and I have to  
programmatically determine which one to use in /etc/hosts.

It''s not pretty, but it''s working well for us.

Thanks,
Avi

--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Puppet Users" group.
To post to this group, send email to puppet-users@googlegroups.com
To unsubscribe from this group, send email to
puppet-users+unsubscribe@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/puppet-users?hl=en
-~----------~----~----~----~------~----~------~--~---

Udo Waechter wrote:
> Would it be possible to rewrite "defined" such that it is not
dependent
> on the parse order of manifest?
> 
> As I understand puppet, this is not easily achievable. I am not sure, 
> though.
Making defined() (and other parse-order dependent stuff) parse-order 
independent would require a complete rework of the way puppet evaluates 
manifests, so that it can solve complex logical problems, like what 
should happen when two parts of a configuration depend on each other? 
Without proof, I believe that a general solution for that would be 
NP-hard (because it might be a SAT instance, 
http://en.wikipedia.org/wiki/Boolean_satisfiability_problem).




Regards, DavidS

--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Puppet Users" group.
To post to this group, send email to puppet-users@googlegroups.com
To unsubscribe from this group, send email to
puppet-users+unsubscribe@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/puppet-users?hl=en
-~----------~----~----~----~------~----~------~--~---