[Puppet Users] What's the benefit of Virtual Resources?

2013-07-12 Thread Christian Flamm 
Hi,
I'm having trouble understanding the added value Virtual Resources provide. 
Let's say I'm having two different modules (that usually are assigned to 
different agents) that both contain a common resource (let's say a user). 
If I want to easily make it possible to assign both modules to the same 
agent - without suffering from the duplicate resource declaration error - 
I could make the resource definition virtual and realize it in different 
modules. See this simplified example.

 cat $modulesdir/virtual/manifests/init.pp
class virtual {
  @user { 'admin': ensure = present }
}

 cat $modulesdir/mailserver/manifests/init.pp
class mailserver {
  realize(User['admin'])
  # some more mailserver stuff...
}

 cat $modulesdir/webserver/manifests/init.pp
class webserver {
  realize(User['admin'])
  # some more webserver stuff...
}

 cat $manifestsdir/nodes.pp
node /somenode/ {
  include virtual
  include mailserver
  include webserver
}


My question: How is that different, more convenient or more flexible than 
extracting that admin user into its own module? Like that:

 cat $modulesdir/adminuser/manifests/init.pp
class adminuser {
  user { 'admin': ensure = present }
}

 cat $modulesdir/mailserver/manifests/init.pp
class mailserver {
  # some more mailserver stuff...
}

 cat $modulesdir/webserver/manifests/init.pp
class webserver {
  # some more webserver stuff...
}

 cat $manifestsdir/nodes.pp
node /somenode/ {
  include adminuser
  include mailserver
  include webserver
}


I guess I'm missing something here, or I'm using it wrong. 
Your help is highly appreciated, 
thanks in advance,
Christian

-- 
You received this message because you are subscribed to the Google Groups 
Puppet Users group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to puppet-users+unsubscr...@googlegroups.com.
To post to this group, send email to puppet-users@googlegroups.com.
Visit this group at http://groups.google.com/group/puppet-users.
For more options, visit https://groups.google.com/groups/opt_out.

Re: [Puppet Users] What's the benefit of Virtual Resources?

2013-07-12 Thread Matthew Burgess 
On 12 July 2013 15:45, Christian Flamm christian.le.fl...@gmail.com wrote:


 My question: How is that different, more convenient or more flexible than
 extracting that admin user into its own module?


I guess the main advantage is one of containing the knowledge of that user
into the thing that needs to know about it.  i.e. the mailserver and
webserver modules know that they need that user in order to manage other
resources (e.g. install a package/start a service).  By splitting it out
the way you have in your second example, something/someone else needs to
know/remember that because node x has module y declared, it also needs
module z to be declared too.  That fact is really internal to the other two
modules, so shouldn't need to be exposed at the node level.

I guess the corollary is; if your webserver module declares a package and a
service resource, why don't you split those out into separate modules?  You
probably wouldn't, right, because they're closely related?  Well, nor
should you split the user out into a separate module.  If it so happens
that 2 modules need to ensure a particular resource is declared, doing so
via the virtual resource functionality is a reasonable way of doing that.

Regards,

Matt.

-- 
You received this message because you are subscribed to the Google Groups 
Puppet Users group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to puppet-users+unsubscr...@googlegroups.com.
To post to this group, send email to puppet-users@googlegroups.com.
Visit this group at http://groups.google.com/group/puppet-users.
For more options, visit https://groups.google.com/groups/opt_out.

Re: [Puppet Users] What's the benefit of Virtual Resources?

2013-07-12 Thread Nan Liu 
On Fri, Jul 12, 2013 at 7:45 AM, Christian Flamm 
christian.le.fl...@gmail.com wrote:

 Hi,
 I'm having trouble understanding the added value Virtual Resources
 provide. Let's say I'm having two different modules (that usually are
 assigned to different agents) that both contain a common resource (let's
 say a user). If I want to easily make it possible to assign both modules to
 the same agent - without suffering from the duplicate resource
 declaration error - I could make the resource definition virtual and
 realize it in different modules. See this simplified example.

  cat $modulesdir/virtual/manifests/init.pp
 class virtual {
   @user { 'admin': ensure = present }
 }

  cat $modulesdir/mailserver/manifests/init.pp
 class mailserver {
   realize(User['admin'])
   # some more mailserver stuff...
 }

  cat $modulesdir/webserver/manifests/init.pp
 class webserver {
   realize(User['admin'])
   # some more webserver stuff...
 }

  cat $manifestsdir/nodes.pp
 node /somenode/ {
   include virtual
   include mailserver
   include webserver
 }


 My question: How is that different, more convenient or more flexible than
 extracting that admin user into its own module? Like that:

  cat $modulesdir/adminuser/manifests/init.pp
 class adminuser {
   user { 'admin': ensure = present }
 }

  cat $modulesdir/mailserver/manifests/init.pp
 class mailserver {
   # some more mailserver stuff...
 }

  cat $modulesdir/webserver/manifests/init.pp
 class webserver {
   # some more webserver stuff...
 }

  cat $manifestsdir/nodes.pp
 node /somenode/ {
   include adminuser
   include mailserver
   include webserver
 }


 I guess I'm missing something here, or I'm using it wrong.
 Your help is highly appreciated,


In this simple case no, but think of a vinn diagram with overlapping groups
(such as user belonging to dbadmin/webadmin and two different teams of
dbadmin webadmin). You can easily realize virtual resource by tags, but not
so easy by splitting to class dbadmin/webadmin/db_and_webadmin ...

HTH,

Nan

-- 
You received this message because you are subscribed to the Google Groups 
Puppet Users group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to puppet-users+unsubscr...@googlegroups.com.
To post to this group, send email to puppet-users@googlegroups.com.
Visit this group at http://groups.google.com/group/puppet-users.
For more options, visit https://groups.google.com/groups/opt_out.

Re: [Puppet Users] What's the benefit of Virtual Resources?

2013-07-12 Thread Christian Flamm 


Am Freitag, 12. Juli 2013 17:03:11 UTC+2 schrieb Nan Liu:

 On Fri, Jul 12, 2013 at 7:45 AM, Christian Flamm 
 christian...@gmail.comjavascript:
  wrote:

 Hi,
 I'm having trouble understanding the added value Virtual Resources 
 provide. Let's say I'm having two different modules (that usually are 
 assigned to different agents) that both contain a common resource (let's 
 say a user). If I want to easily make it possible to assign both modules to 
 the same agent - without suffering from the duplicate resource 
 declaration error - I could make the resource definition virtual and 
 realize it in different modules. See this simplified example.

  cat $modulesdir/virtual/manifests/init.pp
 class virtual {
   @user { 'admin': ensure = present }
 }

  cat $modulesdir/mailserver/manifests/init.pp
 class mailserver {
   realize(User['admin'])
   # some more mailserver stuff...
 }

  cat $modulesdir/webserver/manifests/init.pp
 class webserver {
   realize(User['admin'])
   # some more webserver stuff...
 }

  cat $manifestsdir/nodes.pp
  node /somenode/ {
   include virtual
   include mailserver
   include webserver
 }


 My question: How is that different, more convenient or more flexible than 
 extracting that admin user into its own module? Like that:

  cat $modulesdir/adminuser/manifests/init.pp
 class adminuser {
   user { 'admin': ensure = present }
 }

  cat $modulesdir/mailserver/manifests/init.pp
 class mailserver {
   # some more mailserver stuff...
 }

  cat $modulesdir/webserver/manifests/init.pp
 class webserver {
   # some more webserver stuff...
 }

  cat $manifestsdir/nodes.pp
  node /somenode/ {
   include adminuser
   include mailserver
   include webserver
 }


 I guess I'm missing something here, or I'm using it wrong. 
 Your help is highly appreciated, 


  In this simple case no, but think of a vinn diagram with overlapping 
 groups (such as user belonging to dbadmin/webadmin and two different teams 
 of dbadmin webadmin). You can easily realize virtual resource by tags, but 
 not so easy by splitting to class dbadmin/webadmin/db_and_webadmin ...

 HTH,

 Nan


Do you mean something like this?

 cat $modulesdir/virtual/manifests/init.pp
class virtual {
  @user { ['a', 'b', 'c', 'd']: ensure = present }
}

 cat $modulesdir/mailserver/manifests/init.pp
class mailserver {
  realize(User['a'], User['b'], User['c'])
  # some more mailserver stuff...
}

 cat $modulesdir/webserver/manifests/init.pp
class webserver {
  realize(User['b'], User['c'], User['d'])
  # some more webserver stuff...
}

 cat $manifestsdir/nodes.pp
node /somenode/ {
  include virtual
  include mailserver
  include webserver
}

-- 
You received this message because you are subscribed to the Google Groups 
Puppet Users group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to puppet-users+unsubscr...@googlegroups.com.
To post to this group, send email to puppet-users@googlegroups.com.
Visit this group at http://groups.google.com/group/puppet-users.
For more options, visit https://groups.google.com/groups/opt_out.

Re: [Puppet Users] What's the benefit of Virtual Resources?

2013-07-12 Thread Nan Liu 
On Fri, Jul 12, 2013 at 8:11 AM, Christian Flamm 
christian.le.fl...@gmail.com wrote:



 Am Freitag, 12. Juli 2013 17:03:11 UTC+2 schrieb Nan Liu:

 On Fri, Jul 12, 2013 at 7:45 AM, Christian Flamm 
 christian...@gmail.comwrote:

 Hi,
 I'm having trouble understanding the added value Virtual Resources
 provide. Let's say I'm having two different modules (that usually are
 assigned to different agents) that both contain a common resource (let's
 say a user). If I want to easily make it possible to assign both modules to
 the same agent - without suffering from the duplicate resource
 declaration error - I could make the resource definition virtual and
 realize it in different modules. See this simplified example.

  cat $modulesdir/virtual/manifests/**init.pp
 class virtual {
   @user { 'admin': ensure = present }
 }

  cat $modulesdir/mailserver/**manifests/init.pp
 class mailserver {
   realize(User['admin'])
   # some more mailserver stuff...
 }

  cat $modulesdir/webserver/**manifests/init.pp
 class webserver {
   realize(User['admin'])
   # some more webserver stuff...
 }

  cat $manifestsdir/nodes.pp
  node /somenode/ {
   include virtual
   include mailserver
   include webserver
 }


 My question: How is that different, more convenient or more flexible
 than extracting that admin user into its own module? Like that:

  cat $modulesdir/adminuser/**manifests/init.pp
 class adminuser {
   user { 'admin': ensure = present }
 }

  cat $modulesdir/mailserver/**manifests/init.pp
 class mailserver {
# some more mailserver stuff...
 }

  cat $modulesdir/webserver/**manifests/init.pp
 class webserver {
   # some more webserver stuff...
 }

  cat $manifestsdir/nodes.pp
  node /somenode/ {
   include adminuser
   include mailserver
   include webserver
 }


 I guess I'm missing something here, or I'm using it wrong.
 Your help is highly appreciated,


  In this simple case no, but think of a vinn diagram with overlapping
 groups (such as user belonging to dbadmin/webadmin and two different teams
 of dbadmin webadmin). You can easily realize virtual resource by tags, but
 not so easy by splitting to class dbadmin/webadmin/db_and_**webadmin ...

 HTH,

 Nan


 Do you mean something like this?

  cat $modulesdir/virtual/manifests/**init.pp
 class virtual {
   @user { ['a', 'b', 'c', 'd']: ensure = present }
 }

  cat $modulesdir/mailserver/**manifests/init.pp
 class mailserver {
   realize(User['a'], User['b'], User['c'])
   # some more mailserver stuff...
 }

  cat $modulesdir/webserver/**manifests/init.pp
 class webserver {
   realize(User['b'], User['c'], User['d'])
   # some more webserver stuff...
 }

  cat $manifestsdir/nodes.pp
 node /somenode/ {
   include virtual
   include mailserver
   include webserver
 }


Not quite, the realize function isn't that useful, you should use | |
instead. I'm going to use notify as an example:

class users {
  # admin with different responsibilities:
  @notify { 'a':
tag = ['webadmin', 'dbadmin', 'prod', 'dev']
  }
  @notify { 'b':
tag = ['dbadmin', 'prod', 'dev']
  }
  @notify { 'c':
tag = ['webadmin','prod', 'dev']
  }
  # developers limited to dev environment:
  @notify { 'd':
tag = ['dbadmin', 'dev']
  }
  @notify { 'e':
tag = ['webadmin', 'dev',]
  }
}

class db ($env = 'prod') {
  include users
  Notify | tag == 'dbadmin' and tag == $env |
}

HTH,

Nan

-- 
You received this message because you are subscribed to the Google Groups 
Puppet Users group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to puppet-users+unsubscr...@googlegroups.com.
To post to this group, send email to puppet-users@googlegroups.com.
Visit this group at http://groups.google.com/group/puppet-users.
For more options, visit https://groups.google.com/groups/opt_out.