Puppet users - Feb 2011 - fork from Collection and Realizing resources (puppet-dev)

Hi list (specifically Dan),

I was interested in the snippet you provided in the recent thread
"Collection and Realizing resources" and how it could be used to
safely include both ''app'' and ''db'' class
without causing a conflict in
the user ''bob''. I can''t quite see how that''s
possible, even using
class inheritance and the plusignment operator, you''d run into trouble
overriding the same resource twice (bob). How does the collection
syntax help?

Quoting Dan:

We have only been teaching <| |> in the puppetmaster training as a way
to
realize virtual resources. We do not teach that it is possible to
override
attributes with this syntax as well: <| |> {} (at least in part b/c
the
implications/non-determinism terrify me) , and do not teach that it
actually
effects all resources.

The common example from class is something like:

class db::users {
  user { [''alice'', ''bob'']:
    ensure => present,
    gid => ''dbadmin'',
  }

}

class app::users {
  user { [''charlie'', ''bob'']:
    ensure => present,
    gid => ''webadmin'',
  }

}

class app {
  User<| gid == ''webadmin'' |>
  ...

}

class db {
  User<| gid == ''dbadmin'' |>
  ...

}

so that a machine can safely be a webserver and db server without
conflict.

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On Mon, Feb 14, 2011 at 4:14 AM, luke.bigum
<luke.bigum@fasthosts.co.uk>wrote:
> Hi list (specifically Dan),
>
> I was interested in the snippet you provided in the recent thread
> "Collection and Realizing resources" and how it could be used to
> safely include both ''app'' and ''db''
class without causing a conflict in
> the user ''bob''. I can''t quite see how
that''s possible, even using
> class inheritance and the plusignment operator, you''d run into
trouble
> overriding the same resource twice (bob). How does the collection
> syntax help?
>
ah, those resources should have been virtual:


> Quoting Dan:
>
> We have only been teaching <| |> in the puppetmaster training as a
way
> to
> realize virtual resources. We do not teach that it is possible to
> override
> attributes with this syntax as well: <| |> {} (at least in part b/c
> the
> implications/non-determinism terrify me) , and do not teach that it
> actually
> effects all resources.
>
> The common example from class is something like:
>
> class db::users {
>
should be @user { [''alice'', ''bob'']:

>  user { [''alice'', ''bob'']:
>    ensure => present,
>    gid => ''dbadmin'',
>  }
>
> }
>
> class app::users {
>
should be  @user { [''charlie'', ''bob'']:
>  user { [''charlie'', ''bob'']:
>    ensure => present,
>    gid => ''webadmin'',
>  }
>
> }
>
> class app {
>  User<| gid == ''webadmin'' |>
>  ...
>
> }
>
> class db {
>  User<| gid == ''dbadmin'' |>
>  ...
>
> }
>
> also missing:
include app::users, db::users, db, app


> so that a machine can safely be a webserver and db server without
> conflict.
>
> --
> 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
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>
>
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