On Friday, November 22, 2013 1:18:25 PM UTC-6, Stuart Cracraft wrote:
>
> So now my puppet agent is getting this error in messages:
>
> Date/Timestamp hostname[pid]: Must pass user to Class[abc::def] at
> /etc/puppet/manifests/templates.pp:2 on node hostname
>
> The templates looks like this:
>
> class baseclass {
> include abc::def
> }
>
> node default {
> include baseclass
> }
>
>
> So the question is, how is a variable "user" passed to Class[abc::def] in
> templates.pp?
>
> I thought that I did it in nodes.pp with:
>
> node 'hostname' inherits basenode {
> class { 'abc::def':
> user => "xxx"
> }
> }
>
> but obviously not.
>
>
Since the error refers to file templates.pp rather than nodes.pp, I'm
guessing that your class baseclass is getting evaluated before node
'hostname's node block. You don't show enough for me to be certain that's
happening, but I suppose you also have something like
node basenode {
include baseclass
}
Node 'hostname' inherits from node basenode, so node basenode's node block
is evaluated first, causing class 'baseclass' to be evaluated, which
declares class abc::def without specifying a 'user' parameter.
Let me just say at this point that I would advise you to avoid node
inheritance, or at most to use it sparingly. See
http://docs.puppetlabs.com/puppet/3/reference/lang_node_definitions.html#inheritance.
If you must use node inheritance, then keep these things in mind:
- Each applicable node block is evaluated independently and therefore
must stand on its own, except inasmuch as a child node can rely on its
parent to be evaluated first. Inheritance is basically a chaining
mechanism.
- In particular, node inheritance is not a mechanism for overriding
declarations in the base node. It especially does not provide for
overriding variable declarations in the parent node's scope, though you can
shadow them by declaring a new variable of the same name in the child
node. Doing so is highly inadvisable and unlikely to achieve what you want.
- Deep node inheritance trees are likely to get you into trouble.
- Class inheritance plays reasonably well with node inheritance when you
want to perform some sort of overriding, but class inheritance for the
purpose of overriding resources is out of favor. That's odd, really,
because resource overrides are an essential part of the intended use for
class inheritance. Now, the only use that's in favor involves the
order-of-evaluation side effects of class inheritance.
I would recommend that you look into binding data to your class parameters
via Puppet 3's hiera-based automated data binding facility, and avoid
parameterized-style class declarations altogether. Really, it's the only
mode in which I ever recommend using parameterized classes. It will get
you around the issues you are having with the order of class declaration
evaluation by allowing you to make all declarations of each class
equivalent. That situation is one of the traditional strengths of Puppet's
DSL, but it is broken by use of parameterized-style class declarations.
John
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