Puppet - Resource


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Resources are one of the key fundamental units of Puppet used to design and build any particular infrastructure or a machine. They are mainly used for modeling and maintaining system configurations. Puppet has multiple type of resources, which can be used to define the system architecture or the user has the leverage to build and define a new resource.

The block of Puppet code in manifest file or any other file is called a resource declaration. The block of code is written in a language called Declarative Modelling Language (DML). Following is an example of how it looks like.

user { 'vipin': 
   ensure => present, 
   uid    => '552', 
   shell  => '/bin/bash', 
   home   => '/home/vipin', 
}

In Puppet, resource declaration for any particular resource type is done in code block. In the following example, the user is made up of mainly four pre-defined parameters.

  • Resource Type In the above code snippet, it is the user.

  • Resource Parameter In the above code snippet, it is Vipin.

  • Attributes In the above code snippet, it is ensure, uid, shell, home.

  • Values These are the values that correspond to each property.

Each resource type has its own way of defining definitions and parameters, and the user has the privilege to pick and choose the way he wants his resource to look like.

Resource Type

There are different types of resources available in Puppet which have their own way of functionality. These resource types can be viewed using the “describe” command along with the “-list” option.

[root@puppetmaster ~]# puppet describe --list 
These are the types known to puppet: 
augeas          - Apply a change or an array of changes to the  ... 
computer        - Computer object management using DirectorySer ... 
cron            - Installs and manages cron jobs 
exec            - Executes external commands 
file            - Manages files, including their content, owner ... 
filebucket      - A repository for storing and retrieving file  ... 
group           - Manage groups 
host            - Installs and manages host entries 
interface       - This represents a router or switch interface 
k5login         - Manage the ‘.k5login’ file for a user 
macauthorization - Manage the Mac OS X authorization database 
mailalias       - .. no documentation .. 
maillist        - Manage email lists 
mcx             - MCX object management using DirectoryService  ... 
mount           - Manages mounted filesystems, including puttin ... 
nagios_command  - The Nagios type command 
nagios_contact  - The Nagios type contact 
nagios_contactgroup - The Nagios type contactgroup 
nagios_host     - The Nagios type host 
nagios_hostdependency - The Nagios type hostdependency 
nagios_hostescalation - The Nagios type hostescalation 
nagios_hostextinfo - The Nagios type hostextinfo 
nagios_hostgroup - The Nagios type hostgroup 

nagios_service  - The Nagios type service 
nagios_servicedependency - The Nagios type servicedependency 
nagios_serviceescalation - The Nagios type serviceescalation 
nagios_serviceextinfo - The Nagios type serviceextinfo  
nagios_servicegroup - The Nagios type servicegroup 
nagios_timeperiod - The Nagios type timeperiod 
notify          - .. no documentation .. 
package         - Manage packages 
resources       - This is a metatype that can manage other reso ... 
router          - .. no documentation .. 
schedule        - Define schedules for Puppet 
scheduled_task  - Installs and manages Windows Scheduled Tasks 
selboolean      - Manages SELinux booleans on systems with SELi ... 
service         - Manage running services 
ssh_authorized_key - Manages SSH authorized keys 
sshkey          - Installs and manages ssh host keys 
stage           - A resource type for creating new run stages 
tidy            - Remove unwanted files based on specific crite ... 
user            - Manage users 
vlan            - .. no documentation .. 
whit            - Whits are internal artifacts of Puppet's curr ... 
yumrepo         - The client-side description of a yum reposito ... 
zfs             - Manage zfs 
zone            - Manages Solaris zones 
zpool           - Manage zpools 

Resource Title

In the above code snippet, we have resource title as vipin which is unique for each resource used in the same file of the code. This is a unique title for this user resource type. We cannot have a resource with the same name because it will cause conflicts.

Resource command can be used to view the list of all the resources using type user.

[root@puppetmaster ~]# puppet resource user 
user { 'abrt': 
   ensure           => 'present', 
   gid              => '173', 
   home             => '/etc/abrt', 
   password         => '!!', 
   password_max_age => '-1', 
   password_min_age => '-1', 
   shell            => '/sbin/nologin', 
   uid              => '173', 
} 

user { 'admin': 
   ensure           => 'present', 
   comment          => 'admin', 
   gid              => '444', 
   groups           => ['sys', 'admin'], 
   home             => '/var/admin', 
   password         => '*', 
   password_max_age => '99999', 
   password_min_age => '0', 
   shell            => '/sbin/nologin', 
   uid              => '55', 
} 

user { 'tomcat': 
   ensure           => 'present', 
   comment          => 'tomcat', 
   gid              => '100', 
   home             => '/var/www', 
   password         => '!!', 
   password_max_age => '-1', 
   password_min_age => '-1', 
   shell            => '/sbin/nologin', 
   uid              => '100', 
} 

Listing the Resources of a Particular User

[root@puppetmaster ~]# puppet resource user tomcat 
user { 'apache': 
   ensure           => 'present', 
   comment          => 'tomcat', 
   gid              => '100', 
   home             => '/var/www', 
   password         => '!!', 
   password_max_age => '-1', 
   password_min_age => '-1', 
   shell            => '/sbin/nologin', 
   uid              => '100’, 
}

Attributes & Values

The main body of any resource is made up of a collection of attribute-value pairs. Here one can specify the values for a given resource’s property. Each resource type has its own set of attributes that can be configured with the key-value pairs.

Describe the sub-command that can be used to get more details about a particular resources attribute. In the following example, we have the details about the user resource along with all its configurable attributes.

[root@puppetmaster ~]# puppet describe user 
user 
==== 
Manage users.  This type is mostly built to manage system users, 
so it is lacking some features useful for managing normal users. 

This resource type uses the prescribed native tools for creating groups 
and generally uses POSIX APIs for retrieving information about them.
It does not directly modify ‘/etc/passwd’ or anything. 

**Autorequires:** If Puppet is managing the user's primary group 
(as provided in the ‘gid’ attribute), 
the user resource will autorequire that group. 
If Puppet is managing any role accounts corresponding to the user's roles, 
the user resource will autorequire those role accounts.  

Parameters 
---------- 
- **allowdupe** 
   Whether to allow duplicate UIDs. Defaults to ‘false’. 
   Valid values are ‘true’, ‘false’, ‘yes’, ‘no’.  

- **attribute_membership** 
   Whether specified attribute value pairs should be treated as the 
   **complete list** (‘inclusive’) or the **minimum list** (‘minimum’) of 
   attribute/value pairs for the user. Defaults to ‘minimum’. 
   Valid values are ‘inclusive’, ‘minimum’.  

- **auths** 
   The auths the user has.  Multiple auths should be 
   specified as an array. 
   Requires features manages_solaris_rbac.  

- **comment** 
   A description of the user.  Generally the user's full name.  

- **ensure** 
   The basic state that the object should be in. 
   Valid values are ‘present’, ‘absent’, ‘role’.  

- **expiry**
   The expiry date for this user. Must be provided in 
   a zero-padded YYYY-MM-DD format --- e.g. 2010-02-19. 
   If you want to make sure the user account does never 
   expire, you can pass the special value ‘absent’. 
   Valid values are ‘absent’. Values can match ‘/^\d{4}-\d{2}-\d{2}$/’. 
   Requires features manages_expiry.  

- **forcelocal** 
   Forces the mangement of local accounts when accounts are also 
   being managed by some other NSS  

- **gid** 
   The user's primary group. Can be specified numerically or by name. 
   This attribute is not supported on Windows systems; use the ‘groups’ 
   attribute instead. (On Windows, designating a primary group is only 
   meaningful for domain accounts, which Puppet does not currently manage.)  

- **groups** 
   The groups to which the user belongs. The primary group should 
   not be listed, and groups should be identified by name rather than by 
   GID.  Multiple groups should be specified as an array.  

- **home** 
   The home directory of the user.  The directory must be created 
   separately and is not currently checked for existence.  

- **ia_load_module** 
   The name of the I&A module to use to manage this user. 
   Requires features manages_aix_lam.  

- **iterations** 
   This is the number of iterations of a chained computation of the 
   password hash (http://en.wikipedia.org/wiki/PBKDF2).  This parameter 
   is used in OS X. This field is required for managing passwords on OS X 
   >= 10.8. 
   Requires features manages_password_salt. 

- **key_membership**  

- **managehome** 
   Whether to manage the home directory when managing the user. 
   This will create the home directory when ‘ensure => present’, and 
   delete the home directory when ‘ensure => absent’. Defaults to ‘false’. 
   Valid values are ‘true’, ‘false’, ‘yes’, ‘no’.  

- **membership** 
   Whether specified groups should be considered the **complete list** 
   (‘inclusive’) or the **minimum list** (‘minimum’) of groups to which 
   the user belongs. Defaults to ‘minimum’. 
   Valid values are ‘inclusive’, ‘minimum’.  

- **name** 
   The user name. While naming limitations vary by operating system, 
   it is advisable to restrict names to the lowest common denominator, 
   which is a maximum of 8 characters beginning with a letter. 
   Note that Puppet considers user names to be case-sensitive, regardless 
   of the platform's own rules; be sure to always use the same case when 
   referring to a given user.  

- **password** 
   The user's password, in whatever encrypted format the local 
   system requires. 
   * Most modern Unix-like systems use salted SHA1 password hashes. You can use 
      Puppet's built-in ‘sha1’ function to generate a hash from a password. 
   * Mac OS X 10.5 and 10.6 also use salted SHA1 hashes.  

Windows API 
   for setting the password hash. 
   [stdlib]: https://github.com/puppetlabs/puppetlabs-stdlib/ 
   Be sure to enclose any value that includes a dollar sign ($) in single 
   quotes (') to avoid accidental variable interpolation. 
   Requires features manages_passwords.  

- **password_max_age** 
   The maximum number of days a password may be used before it must be changed. 
   Requires features manages_password_age.  

- **password_min_age** 
   The minimum number of days a password must be used before it may be changed. 
   Requires features manages_password_age.  

- **profile_membership** 
   Whether specified roles should be treated as the **complete list** 
   (‘inclusive’) or the **minimum list** (‘minimum’) of roles 
   of which the user is a member. Defaults to ‘minimum’. 
   Valid values are ‘inclusive’, ‘minimum’.  

- **profiles** 
   The profiles the user has.  Multiple profiles should be 
   specified as an array. 
   Requires features manages_solaris_rbac.  

- **project** 
   The name of the project associated with a user. 
   Requires features manages_solaris_rbac.  

- **uid** 
   The user ID; must be specified numerically. If no user ID is 
   specified when creating a new user, then one will be chosen 
   automatically. This will likely result in the same user having 
   different UIDs on different systems, which is not recommended. This is 
   especially noteworthy when managing the same user on both Darwin and 
   other platforms, since Puppet does UID generation on Darwin, but 
   the underlying tools do so on other platforms. 
   On Windows, this property is read-only and will return the user's 
   security identifier (SID). 


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