Featured Post

Directory environments in Puppet

Environments are individual groups of Puppet agents each environment have there own completely different manifests and module-paths. This basically is useful for testing changes to our Puppet code before implementing them on production machines. There are two types of implementation of environments structure in Puppet one if directory based and another is config file based here we will see bit of an insight about directory based. As usual for more information about this you can visit puppetlabs official website. On the master node: Append following details in puppet.conf which is placed under /etc/puppet or /etc/puppetlabs/puppet:     Under [main] section add a variable called confdir with value as /etc/puppet or /etc/puppetlabs/puppet     confdir=/etc/puppet Then add information regarding environments/manifests and modulepath in it.      #environments     environmentpath = $confdir/environments     default_manfiest = $confdir/manifests     basemodulepath =
Post a Comment

Puppet modules???

*Modules in puppet*

Modules are a way of arranging manifests/files/templates in puppet. Why they are arranged like this?? So that they can be automatically called by the puppet master when needed.

What is the location of module??
  • Default location, you can find it by firing below command:
[root@puppet modules]# puppet master --genconfig | grep modulepath
    modulepath = /etc/puppet/modules:/usr/share/puppet/modules
[root@puppet modules]#

  • User defined location, If in-case you want to use the user defined location to fetch the modules so that puppet master can use it you need to use a option called --modulepath while firing the command.
[root@puppet manifests]# puppet apply site.pp --modulepath=/tmp/mods/
notice: Finished catalog run in 0.26 seconds
[root@puppet manifests]#


Structure of a module:

modules/
└── ntp
    ├── files
    │   ├── ntp.conf.debian
    │   └── ntp.conf.el
    ├── manifests
    │   └── init.pp
    └── templates
        ├── ntp.conf.debian.erb
        └── ntp.conf.el.erb

In the above example you can see the parent directory is modules/, under that there one directory called ntp/ [that's our module] under which there are 3 directories called files/ , manifests/ , templates/ which includes there respective files.

files/: It contains static files, which the managed agent nodes can download to get themselves to their desired state. In this case there are ntp.conf.debian[Ubuntu/Kubuntu/Debian] and ntp.conf.el [RedHat/Fedora/CentOS].

templates/: It contains dynamic files, which can be used by the manifests [indirectly by the puppet master] to create a config file so that those files can be used by the agent nodes to get themselves to their desired state. In this case there are ntp.conf.debian.erb[Ubuntu/Kubuntu/Debian] and ntp.conf.el.erb [RedHat/Fedora/CentOS].

  • ERB is a feature of Ruby that enables you to create any kind of text from templates. 
manifests/: The most important directory of the module without this your module is really of no use. It contains all the .pp files which are relevant for a module. Most importantly it should have a init.pp.

It contains one class named [YOUR MODULE NAME] and this class’s name must match the module’s name. So suppose in this case my module's name is ntp so there must be a class called ntp in init.pp file.
[root@puppet puppet]# cat modules/ntp/manifests/init.pp
class ntp {
case $operatingsystem {
    CentOS , RedHat , Fedora: {
    $service_name = 'ntpd'
...........
...........
...........
    subscribe => File['ntp.conf'],
    }
}
[root@puppet puppet]#

There are various important modules which are supplied by "The Puppet Forge" you can get them downloaded and use it.

By below command you can search the modules which are there in puppet forge and get them installed:

[root@puppet puppet]# puppet module search httpd
Searching http://forge.puppetlabs.com ...
NAME      DESCRIPTION            AUTHOR          KEYWORDS   
.............
............. httpd mod_jk tomcat apache     @domcleal       ssh nrpe sshd host grub httpd 
eshamow-pe_httpd           UNKNOWN                                       @eshamow                                    
example42-lighttpd             Puppet module for lighttpd                                        @example42      
.............
............. lighttpd webserver example42                              @proudsourcing  php5 ioncube debian httpd oxid
puppetlabs-apache     Puppet module for Apache      @puppetlabs     web httpd rhel ssl wsgi proxy 
.............
.............
[root@puppet puppet]#

Now suppose you want to install the apache module provided by puppetlabs.

[root@puppet puppet]# puppet module install puppetlabs-apache
Preparing to install into /etc/puppet/modules ...
Downloading from http://forge.puppetlabs.com ...
Installing -- do not interrupt ...
/etc/puppet/modules
└─┬ puppetlabs-apache (v1.1.1)
  ├── puppetlabs-concat (v1.1.0)
  └── puppetlabs-stdlib (v4.3.2)
[root@puppet puppet]#

Or if you want to uninstall it use the option uninstall and it will be removed.

[root@puppet apache]# puppet module uninstall puppetlabs-apache
Preparing to uninstall 'puppetlabs-apache' ...
Removed 'puppetlabs-apache' (v1.1.1) from /etc/puppet/modules
[root@puppet apache]#

How to create a puppet module???

Comments

Post a Comment

Popular posts from this blog

Exec in Puppet

Exec is a very useful resource type present in Puppet which is used to executes external commands. Puppet basically runs as a daemon in which it executes every 30 mins. So while writing an exec resource type make sure that the exec resource must be able to run multiple times without causing any harm to the machine i.e. it must be idempotent. Suppose you just want to run a command like reload a service for that what you can do is? exec { "reload httpd": command => "service httpd reload", path => "/usr/local/bin/:/bin/:/sbin/", } Lets break this line by line: exec { "reload httpd": This specifies that the resource type is exec type and has a human readable name as "reload httpd". command => "service httpd reload", This specified which command to execute when puppet is executed. path => "/usr/local/bin/:/bin/:/sbin/", This specifies where the binary service can be found in your mac
Read more

Un-revoke the revoked certificate in Puppet

If you revoked or deleted the puppet agent’s certificate accidentally. Basically it is nearly impossible un-revoke a certificate. The solution is to recover all revoked certificates then revoke other certificates which don’t need to be recovered. But if in-case you have thousands of revoked certificates then its a bit lengthy process. Second one is to generate a new certificate for the client/agent and get that signed by the puppet master.  List of all the certificates which are signed at the moment:  [root@puppet requests]# puppet cert list --all + "fedora20"            (AE:57:40:F6:FC:E1:CD:DD:ED:EE:1E:8C:A7:81:0D:76) + "kubuntu14.sunny.com" (20:6B:A1:E2:A3:DE:B1:95:C8:80:4C:B4:27:2B:C0:A2) + "puppet.sunny.com"    (68:12:76:3C:D0:F8:0D:2D:8B:2B:40:E7:49:2D:55:5B) (alt names: "DNS:puppet", "DNS:puppet.sunny.com") + "rhel6.sunny.com"     (DC:6E:B1:FC:27:1D:7A:2A:85:E7:3E:3A:24:8B:64:D3) [root@puppet requests]# N
Read more

Dry run in Puppet --noop

 Dry run in puppet is a powerful feature given by puppet. This basically is used to test your Puppet manifests on any of the environment without actually making any changes to the machine. To dry-run Puppet, --noop flag needs to be used. Puppet’s ‘noop’ (no-operation) mode shows you what would happen, but actually doesn’t do anything :) This basically helps us for debugging stuff. For instance: [root@puppet manifests]# puppet apply site.pp --noop notice: /Stage[main]/Sudo/File[/etc/sudoers]/content: current_value {md5}e81452ad78198a79772447b1f2b3b614, should be {md5}e2d690ebe349d93efa84146eb854c987 (noop) notice: Class[Sudo]: Would have triggered 'refresh' from 1 events notice: /Stage[main]/Ssh::Service/Service[sshd]/ensure: current_value stopped, should be running (noop) notice: Class[Ssh::Service]: Would have triggered 'refresh' from 1 events notice: Stage[main]: Would have triggered 'refresh' from 2 events notice: Finished catalog run in 2.75 seco
Read more