Just getting started with Puppet, and I'm having trouble with my first template. It should be very easy, but I can't figure it out.
I have a module "base" at
/etc/puppet/modules/base/
./manifests
./manifests/service.pp
./manifests/init.pp
./manifests/params.pp
./manifests/config.pp
./manifests/install.pp
./templates
./templates/puppet.conf.erb
There's other stuff, but it's not necessary.
base/manifests/init.pp:
class base {
include base::install, base::service, base::config, base::params
}
base/manifests/config.pp
class base::config {
include base::params
File {
require => Class["base::install"],
ensure => present,
owner => root,
group => root,
}
file { "/etc/puppet/puppet.conf":
mode => 0644,
content => template("base/puppet.conf.erb"),
require => Class["base::install"],
nofity => Service["puppet"],
}
...
base/manifests/params.pp
class base::params {
$puppetserver = "pup01.sdirect.lab"
}
Finally the interesting part of the template at base/templates/puppet.conf.erb
...
server=<% puppetserver %>
The error message:
err: Failed to parse template base/puppet.conf.erb: Could not find
value for 'puppetserver' at
/etc/puppet/modules/base/manifests/config.pp:13 on node ...
I don't get what the problem is. I've copied this part straight out of the Pro Puppet book.
Could someone show me where $puppetserver should be defined and how?
The issue is that the name "puppetserver" needs to be fully qualified so Puppet can find the value, since it's defined in a different scope to the one the template is evaluated in.
The variable is defined in base::params so can only be referred to simply as "puppetserver" in that scope. When you're evaluating the template from within base::config, you're in a different scope and so you can't refer to the variable simply by its short name. The "include" adds the other class to the catalog, but doesn't change these rules.
This means to access it, you fully qualify it with the class name: base::params::puppetserver. If you were using it in the manifest itself, this would be $base::params::puppetserver. You'll see similar examples in Pro Puppet in the ssh::config and ssh::service classes where it refers to "ssh_service_name" in the params class (pages 43-45).
To access the variable in a template it's a bit different, use scope.lookupvar("base::params::puppetserver"). Taking your full example and adding a missing equals sign (to output the value) in the template:
...
server=<%= scope.lookupvar("base::params::puppetserver") %>
There's a bit more information about scoping on the Scope and Puppet as of 2.7 page.
(Edit: looks like it's listed on the confirmed errata page too with the same solution.)
Answer #1 is technically correct, but results in very verbose templates.
You can shorten them by bringing variable values from other classes into your own class scope:
class base::config {
include base::params
$puppetserver = $base::params::puppetserver
...
}
And then use them in your template as expected:
server=<% puppetserver %>
You could also use inherits:
class puppet::config inherits puppet::params {
....
In this way you don't have to define $puppetserver again in this class.
Related
I'm learning puppet (v6), and trying to understand how to set class parameters when a specific node needs an additional parameter, but uses the same class. Maybe a little fuzzy on the terminology, but here's what I'm working on:
MyNode1 needs sshd configured to use a banner and timeout, so using ghoneycutt-ssh, I include the ssh class with parameters:
/modules/MyModule/manifests/MySSH.pp
# Configures SSH
class MyModule::MySSH {
# Using ssh module
class { '::ssh':
sshd_client_alive_count_max => 0,
sshd_client_alive_interval => 900,
sshd_config_banner => '/etc/MyBanner.txt',
}
}
Now I have a second node MyNode2, which requires MySSH above, and also needs to disable forwarding. I started with something like this, where I define only the additional parameter in its own class:
/modules/MyModule/manifests/MySSH_Node2.pp
class MyModule::MySSH_Node2 {
class { '::ssh':
sshd_allow_tcp_forwarding => 'no',
}
}
Then define MyNode2 to include both in my site definition, hoping that puppet merges my ::ssh definitions:
/manifests/site.pp
node MyNode1 {
include MyModule::MySSH
}
node MyNode2 {
include MyModule::MySSH
include MyModule::MySSH_Node2
}
I understand that the above example doesn't work due to error Duplicate declaration: Class[Ssh]. I also tried overriding the class with a new parameter:
class MyModule::MySSH_Node2 {
Class[ssh] {
sshd_allow_tcp_forwarding => 'no',
}
}
But it seems this is not allowed either: Error: Resource Override can only operate on resources, got: Class[ssh]-Type
I'm not sure what the best way to add parameters is. I know I can create a manifest that includes all the parameters needed for this node and apply that instead, but then I end up with duplicate code everywhere.
Is there a reasonable way in modern puppet to assign and merge class parameters like this in puppet?
How to overwrite defined type in nodes.pp? I want to able to set custom domain using nodes.pp. Case Default isn't an option.
I'm using puppet 6.0..
The following method doesn't work. It says Could not find declared class resolv::resolv_config.
It looks like it used to work in 3.0 according to this answer.
nodes.pp
node "test001" {
class { 'resolv::resolv_config':
domain => "something.local",
}
}
modules/resolv/manifests/init.pp
class resolv {
case $hostname {
/^[Abc][Xyz]/: {
resolv:resolv_config { 'US':
domain => "mydomain.local",
}
}
}
}
define resolv::resolv_config($domain){
file { '/etc/resolv.conf':
content => template("resolv/resolv.conf.erb"),
}
}
resolv.conf.erb
domain <%= #domain %>
There are a couple of problems here, but the one causing the "could not find declared class" error is that you are using the wrong syntax for declaring a defined type. Your code should be something like this:
node "test001" {
resolv::resolv_config { 'something.local':
domain => "something.local",
}
}
There are examples of declaring defined types in the documentation, https://puppet.com/docs/puppet/latest/lang_defined_types.html.
Once you get that working, you'll find another problem, in that this definition
define resolv::resolv_config($domain){
file { '/etc/resolv.conf':
content => template("resolv/resolv.conf.erb"),
}
}
will cause a error if you try to declare more than one resolv::resolv_config, because they will both try to declare the /etc/resolv.conf file resource. You almost certainly wanted to use a file_line resource.
I want to override parameters of base nodes. What I want to get is a pattern like this:
# File manifests/nodes.pp
node myDefault {
class { 'my::common::puppet_setup':
service => 'enable',
pushable => 'disable',
}
# Do lots of default things ...
}
node 'myFirstNode' inherits myDefault {
# Do something ...
}
node 'mySecondNode' inherits myDefault {
class { 'my::common::puppet_setup::params':
service => 'disable',
pushable => 'enable',
}
}
I understood the the puppet documentation, i could do this by writing my module like this:
# File modules/my/manifests/common/puppet_setup.pp
class my::common::puppet_setup (
$pushable = $my::common::puppet_setup::params::pushable,
$service = $my::common::puppet_setup::params::service,
) inherits my::common::puppet_setup::params {
# package that configures puppet node
# input value validation
validate_re($pushable, ['^enable$', '^disable$', '^ignore$', ])
validate_re($service, ['^enable$', '^disable$', '^ignore$', '^cron$', ])
# setup puppet, start or disable agent, put ssh keys for push ...
}
class my::common::puppet_setup::params {
$pushable = 'enable'
$service = 'enable'
$puppetserver = 'puppet.my.site.de'
case $::osfamily {
'Debian': {
}
default: {
fail("not implemented yet for {::operatingsystem}")
}
}
}
The Documentations on puppet website says:
When a derived class is declared, its base class is automatically declared first (if it wasn’t already declared elsewhere).
But i get this error (some indentation added):
mySecondNode# puppet agent --test --environment dev_my
Error: Could not retrieve catalog from remote server:
Error 400 on SERVER: Duplicate declaration:
Class[My::Common::Puppet_setup::Params] is already declared;
cannot redeclare at /.../puppet/manifests/nodes.pp:16 on node mySecondNode
Warning: Not using cache on failed catalog
Error: Could not retrieve catalog; skipping run
I'm reading on this for a week and i guess my understanding ist totally wrong somewhere, although i used the puppetlabs ntp modules as an example.
what am i missing?
You should check Inheritance section from http://docs.puppetlabs.com/puppet/latest/reference/lang_node_definitions.html
Puppet treats node definitions like classes. It does not mash the two together and then compile the mix; instead, it compiles the base class, then compiles the derived class, which gets a parent scope and special permission to modify resource attributes from the base class.
One of the good solutions is to use roles and profiles, there's a great blog post about it:
http://garylarizza.com/blog/2014/02/17/puppet-workflow-part-2/
You can use virtual resources :
http://docs.puppetlabs.com/guides/virtual_resources.html
I realise that it's generally a good idea to create params.pp in the module with modulename::params class and inherit that in modulename class to handle parameters in a separate file. How do I do that if instead of class, I am creating a definition?
Just to clarify, I'm using a definition to be able to install multiple versions of the same application on the server.
Good question. Since there is no inheritance available for defined types in Puppet the params.pp patterns can not be reproduced in the exact same way for defined types as for classes. There is another way though.
The following code outputs 'hello world' via the Foo['bar'] defined type:
class params {
$msg = 'hello world'
}
define foo($msg = $params::msg ) {
notify{ $msg: }
}
foo { 'bar': }
include params
Now, for the above to function it is necessary for params to be included. Otherwise the Puppet parser will complain that the class params has not been evaluated and therefore the $params::msg variable can not be resolved.
It is not necessary to provide ordering between the inclusion of params and the definition of bar, since in Puppet classes are always evaluated before defined types. If this would not be so the above would likely cause the same evaluation problem and you would have to write:
foo { 'bar':
require => Class['params'] # <- not necessary
}
include params
So for this to work in a module foo you can simply add a params class as you are used to and start your init.pp with:
include foo::params
define foo($x = $foo::params::x, $y = $foo::params::y, ...)
One important note
Before you happily proceed with the params.pp pattern I advise you to read this blog post: the problem with params.pp
using puppet, i need to create three files, with this content:
/tmp/f1.txt: hello /tmp/f1.txt
/tmp/f2.txt: hello /tmp/f2.txt
/tmp/f3.txt: hello /tmp/f3.txt
i try as follows:
$path="/tmp/"
$my_files = ["$path/f1.txt", "$path/f2.txt", "$path/f3.txt"]
file { $my_files:
ensure => file,
content => "hello $name\n",
}
however this does not work because $name is undefined.
is there a variable that gets instantiated for each 'iteration' and that i can use?
ps: i am aware that i could create a new resource type as follows:
define file_with_content {
file { $name:
ensure => file,
content => "hello $name\n",
}
}
$path="/tmp/"
$my_files = ["$path/f1.txt", "$path/f2.txt", "$path/f3.txt"]
file_with_content { $my_files: }
but this requires creating a new resource type,
and I cannot do this in my context (which is not explained here).
the question is, how to modify the first code to make it work, without defining a new resource type, nor executing shell code?
You only can access the namevar for defined types. For Puppet's resources, the results are unpredictable - for example, $name for File will give you main, or the current stage. Additionally, you cannot pass/utilize extra parameters to Puppet's resources as they have their own set of parameters already.
The standard solution has been to wrap the File declaration in a defined type like here, like your first. Perhaps you can explain why that cannot be used, so some other solution could be devised?