resource ordering synchronization issue "->" doesn't work? - puppet

I have encounter really weird behaviour which goes against what I have learned, tutorial says etc. So I would be glad if someone could explain why that is happening.
I have a role module which is made up of composition of profiles (role-profile pattern). My role consists:
class role::lab_prg_c2_dn inherits lab_prg_c2 {
class { 'profile::cluster_data_node':
namenode_fqdn => $role::lab_prg_c2::namenode_fqdn,
secondarynamenode_fqdn => $role::lab_prg_c2::secondarynamenode_fqdn,
}
->
class{'bigdatasolution':}
}
First class installs technology and second one installs our components and items which are build on top of technology. Hence the technology need to be installed first, thats the reason for "->" dependency. However this seems to me doesn't work correctly. As components from class 'bigdatasolution' are installed somewhere before the class profile::cluster_data_node finishes.
I tried to use require => Class['profile::cluster_data_node'] but that doesn't make any difference!
The content of class{'bigdatasolution':} :
class bigdatasolution {
$hdfs_default_conf = '/usr/local/hadoop.hdfs.conf'
$hbase_default_conf = '/usr/local/hadoop.hbase.conf'
include symlinks
include bdjar
}
Symlinks - create symlinks for the configuration installed in class profile::cluster_data_node and are not directly managed - it will be presented when actually specified package get installed.
bdjar - add our jar to a technology library so content is as follows:
class bigdatasolution::bdjar {
file { "/usr/lib/hadoop/lib/bigdata-properties.jar":
ensure => present,
mode => 0644,
group => 'root',
owner => 'root',
source => "puppet:///modules/bigdatasolution/bigdata-properties.jar"
}
}
I even tried to put require => "technologycalClass" here but that doesn't help either.
Can someone please help me understand what's wrong and how that should be solved properly?
I Using puppet 3 and ordering is specified explicetly - so no arbitrary ordering set by puppet should happen.
Thanks

If your 'profile::cluster_data_node' class 'includes' other classes/modules they will have no dependency ordering with the 'bigdatasolution' class.
I see you actually do include symlinks and bdjar. Basically every piece of ordering you want to have in puppet, you need to write explicitly.
Here you should replace the include statements with require, that way the class cluster_data_node will require the other two modules to complete before it says it has completed. Include is a pretty lose way of importing things in puppet and in my opinion is best to just avoid it and go with explicit require statements instead.
TL;DR: included modules have no transitive ordering; required modules do.

Related

Puppet manifest: Overriding default variables in Hash

I've been handed the code for a Puppet module which was written by someone else. I've been tasked with getting it working in an actual Puppet environment.
I'm struggling to override defaults in the module in the manifest file. Hopefully this is a syntax issue, and not a issue with the init class.
In init.pp:
class our_module(
# Defaults to be overridden in the manifest file
Hash $config = {
'id' => '38e18a',
'secret' => 'donttellanyone',
'path' => '/test/path'
}
){
# Logic here...
}
How can I override these attributes? I've tried the following which gives my an InvalidCredentialsException:
node 'my_node' {
class { 'our_module':
config => {
id => 'newid',
secret => 'newsecret',
path => '/newpath
}
}
I'm new to Puppet and still getting my head around the docs and the syntax.
Given class our_module as presented in the question, this variation on the node block is valid for declaring that class and customizing its config parameter:
node 'my_node' {
class { 'our_module':
config => {
id => 'newid',
secret => 'newsecret',
path => '/newpath'
}
}
}
Hopefully this is a syntax issue, and not a issue with the init class.
If what you're really using takes the same form as above, then I'm sorry to have to tell you that the problem is not with your class declaration. If your Puppet runs are successful for nodes that do not declare class our_module, then my conclusion would be that the issue is indeed with the class implementation.
I've tried the following which gives my an InvalidCredentialsException
I am disinclined to think that that arises during catalog building. I cannot completely rule out the possibility, but that sure looks like a Java exception, whereas the catalog builder is implemented mainly in Ruby. It could be coming from puppetserver, Puppet's Java-based server front end, but that would not depend on whether your manifests declare a particular class. My crystal ball suggests that the our_module implementation is Execing a Java program when it is applied to the client, and that it is that program that is throwing the exception.
Some of those possibilities could be related to bad class parameter data, but I don't see any reason to think that the issue arises from a syntax error.

Puppet: Class Ordering / Containment - always wrong order

I read a lot about ordering puppet classes with containment (iam using Puppet 6). But it still does not work for me in one case. Maybe my english is not good enough and i miss something. Maybe somebody know what iam doing wrong.
I have a profile to installing a puppetserver (profile::puppetserver). This profile has three sub-classes which I contain within the profile::puppetserver
class profile::puppetserver(
) {
contain profile::puppetserver::install
contain profile::puppetserver::config
contain profile::puppetserver::firewall
}
That works fine for me. Now I want to expand this profile and install PuppetDB. For this, i use the puppetdb module from puppet forge:
So what i do is add profile::puppetserver::puppetdb and the contain to the profile::puppetserver
class profile::puppetserver::puppetdb(
) {
# Configure puppetdb and its underlying database
class { 'puppetdb': }
# Configure the Puppet master to use puppetdb
class { 'puppetdb::master::config': }
}
When i provision my puppetserver first and add the profile::puppetserver::puppetdb after it, puppetdb installs and everything works fine.
If I add it directly with contain, and provisioning everything at once, it crashes. It's because the puppetdb module is installed randomly during my master server installs (and also the postgresql server and so on). That ends in my puppetserver is not running and my puppetdb generate no local ssl certificates and the service doesn't comes up.
What i try first:
I installed the puppetdb Package in my profile::puppetserver::puppetdb directly and use the required flag. It works when i provision all at once.
class profile::puppetserver::puppetdb (
) {
Package { 'puppetdb':
ensure => installed,
require => Class['profile::puppetserver::config']
}
}
So i think i could do the same in the code above:
class profile::puppetserver::puppetdb(
) {
# Configure puppetdb and its underlying database
class { 'puppetdb':
require => Class['profile::puppetserver::config']
}
# Configure the Puppet master to use puppetdb
class { 'puppetdb::master::config':
require => Class['profile::puppetserver::config']
}
}
But this does not work...
So i read about puppet class containment and ordering by chains. So i did this in my profile::puppetserver
class profile::puppetserver(
) {
contain profile::puppetserver::install
contain profile::puppetserver::config
contain profile::puppetserver::firewall
contain profile::puppetserver::puppetdb
Class['profile::puppetserver::install'] ->
Class['profile::puppetserver::config'] ->
Class['profile::puppetserver::firewall'] ->
Class['profile::puppetserver::puppetdb']
}
But it still does not have any effect... he still starts to install postgresql and the puppetdb package during my "puppetserver provisioning" in the install, config, firewall steps.
How i must write the ordering, that all things from the puppetdb module, which i call in profile::puppetserver::puppetdb, only starts when the rest of the provisioning steps are finished?
I really don't understand it. I think maybe it haves something to do with the fact, that i declare classes from the puppetdb module inside of profile::puppetserver::puppetdb and not the directly Resource Type. Because when i use the Package Resource Type with the Require Flag, it seems to work. But i really don't know how to handle this. I think there must be a way or?
I think maybe it haves something to do with the fact, that i declare
classes from the puppetdb module inside of
profile::puppetserver::puppetdb and not the directly Resource Type.
Because when i use the Package Resource Type with the Require Flag, it
seems to work.
Exactly so.
Resources are ordered with the class or defined-type instance that directly declares them, as well as according to ordering parameters and instructions applying to them directly.
Because classes can be declared multiple times, in different places, ordering is more complicated for them. Resource-like class declarations such as you demonstrate (and which you really ought to avoid as much as possible) do not imply any particular ordering of the declared class. Neither do declarations via the include function.
Class declarations via the require function place a single-ended ordering constraint on the declared class relative to the declaring class or defined type, and declarations via the contain function place a double-ended ordering constraint similar to that applying to all resource declarations. The chaining arrows and ordering metaparameters can place additional ordering constraints on classes.
But i really dont know how to handle this. I think there must be a way or?
Your last example shows a viable way to enforce ordering at the level of profile::puppetserver, but its effectiveness is contingent on each of its contained classes taking the same approach for any classes they themselves declare, at least where those third-level classes must be constrained by the order of the second-level classes. This appears to be where you are falling down.
Note also that although there is definitely a need to order some things relative to some others, it is not necessary or much useful to try to enforce an explicit total order over all resources. Work with the lightest hand possible, placing only those ordering constraints that serve a good purpose.

Puppet: Declaring a class with inheritance

I currently have two classes that I created within /etc/puppet/modules/params/manifests/init.pp
class modulename ($variable_name = 'Any string') inherits modulename::params{
file { '/tmp/mytoplevelclass.sh' :
mode => '644',
ensure => 'present',
content => $variable_name
}
}
class modulename::params{
}
However, I am having an issue declaring these classes in /etc/puppet/manifests/site.pp. Currently, I have it written as
node default { #client
class { 'modulename':}
class { 'modulename::params':}
}
I know that this is incorrect because when I run puppet agent -t on the client I get an error stating
Could not find declared class modulename at /etc/puppet/manifests/site.pp
I have tried several different configurations and still am unsure on what to do.
Puppet determines the file in which it expects to find a class's definition based on the class's fully-qualified name. The docs go into it in some detail; in particular, you should review the Module Fundamentals. (I am guessing that you are on Puppet 3, but the details I am about to discuss are unchanged in Puppet 4.)
Supposing that /etc/puppet/modules is a directory in your modulepath, it is a fine place to install (or write) your modulename module, as indeed you indicate you are doing. If it is not in your module path, then you'll want either to move your module to a directory in the module path, or to add that directory to the module path. I assume that you will resolve any problem of this sort via the latter alternative, so that /etc/puppet/modules/modulename is a valid module directory.
Now, class 'modulename' is a bit special in that its name is also a module name; as such, it should be defined in /etc/puppet/modules/modulename/manifests/init.pp. Class modulename::params, on the other hand, should follow the normal pattern, being defined in /etc/puppet/modules/modulename/manifests/params.pp. I anticipate that Puppet will find the definitions if you put the definitions in the correct files.
Bonus advice:
Use include-like class declarations in your node blocks, not resource-like declarations
Your node blocks probably should not declare modulename::params at all

How do I interpret dependency cycles in puppet?

I have a puppet program that I'm trying to use stages in to better manage timing, but when I try that, nothing happens. I then tried to just use a dependency chain, but that throws back this error:
Error: Could not apply complete catalog: Found 1 dependency cycle:
(Anchor[apt::ppa::ppa:saltstack/salt] => Apt::Ppa[ppa:saltstack/salt] => class[Pp_package_manager] => Class[User_manager] => User_manager::User[coder] => User[coder] => File[/etc/default/perfectpitch] => Class[Pp_package_manager])
I'm trying to understand what this error is telling me, but the => signs are confusing the heck out of me. I also tried to open up the .dot file using the --graph flag, but that just confuses me as well. I'd love a guiedhttps://gist.github.com/supereman16/1ff46d6fbb1c7ac9b709.
I'd love a guide on how to interpret these and possibly some help with where the problem actually is. Any help will be greatly appreciated in helping me understand this error, and the steps I should take to find the problem and fix it. Thanks in advance!
Please read this article about relations and ordering in puppet.
In summary.
Puppet is a declarative language, where you describe a desired state of your system (not how to achieve it). So when it compiles manifests code to catalogue, it tries to establish order in which resources should be realized achieve desired state (it creates graph of dependencies).
E.g you cannot run mysql server unless you install mysql package.
Generally puppet properly solves relationships between resources. But sometimes it needs help. For each resource you can manually define relationship between other resources, using before, require, notify, subscribe metaparameters. Unfortunately, using these metaparameters you can easily create a cycle of dependencies.
E.g
file { a: require => File['b'] }
file { b: require => File['c'] }
file { c: require => File['a'] }
Such declaration of resources will create a cycle of dependencies causing compilation error similar to what you have.
It the message you provide, a => b means do resource a before resource b.
You got a cycle of dependencies: ...=> class[Pp_package_manager] => ... Class[Pp_package_manager].
I'm guessing you have defined relationships File[/etc/default/perfectpitch] => Class[Pp_package_manager] and class[Pp_package_manager] => Class[User_manager] , which causes an error.

Puppet - test if a package already defined?

I'm writing some puppet modules and have a package defined in two modules hence get the following error:
err: Could not retrieve catalog from remote server: Error 400 on SERVER: Duplicate definition: Package[gnome-session-fallback] is already defined in file /etc/puppet/modules/vnc4server/manifests/init.pp at line 3; cannot redefine at /etc/puppet/modules/vino/manifests/init.pp:7 on node l
Hence want to ensure that the package has not already been defined but the following does not work:
if ! defined ('gnome-session-fallback') {
package { 'gnome-session-fallback':
ensure => installed,
}
}
Can anyone suggest how to fix this, and on the broader scale, what is the "proper" approach to avoiding clashes such as this in modules?
You are missing Package[] inside defined(). The correct way to do it:
if ! defined(Package['gnome-session-fallback']) {
package { 'gnome-session-fallback':
ensure => installed,
}
}
The cleanest way to do this is to use the ensure_resource function from puppetlabs-stdlib:
ensure_resource('package', 'gnome-session-fallback', {'ensure' => 'present'})
To answer my own question about what the "proper" approach is : This issue is discussed at https://groups.google.com/forum/?fromgroups=#!topic/puppet-users/julAujaVsVk and jcbollenger offers what looks like a "best-practice" solution - resources which are defined multiple times should be moved into their own module and included into the classes on which they depend. I applied this and solved my problem.
This doesn't actually answer why "if !defined" fails however...
One cleaner way (among multiple ways) is to create a virtual package resource and then realize it. You can realize the same virtual package multiple times without error.
#package { 'gnome-session-fallback':
ensure => installed,
}
And then where you need it:
realize( Package[ 'gnome-session-fallback' ] )

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