Puppet Administration [In progress]

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...

Puppet agent ==> Sends node's information and its facts to the master node and requests for Catalog [Complied manifests]. Puppet master checks who is this ? if this machine is authorized[Have a signed certificate or not?] to communicate with it and what all stuff do this machine needs. If incase this is the authorized one. Puppet master will gather all the related manifests and compile them to a catalog and then will send that catalog to the agent node. Puppet agent then will download & apply that catalog to get to the desired state and will create a [success/failure] report for the puppet master. Related docs: Puppet master   Puppet agent

 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...

Puppet can be used as a standalone model or as agent/server model. There are basically 2 types of puppet version available in market. Free version of puppet. Enterprise version of puppet which is also know as puppet-enterprise. Here we will be installing the free version of puppet. 0. Enable EPEL repo, you can find the latest version of EPEL on below URL: https://fedoraproject.org/wiki/EPEL 1. Install prerequisites before installing puppet [root@rhel6 ~]# yum install ruby-shadow ruby ruby-libs 2. Resolve the dependencies like ruby(selinux). 3. Install puppetmaster and facter on the server node. [root@rhel6 ~]# yum install puppet-server facter 4. Install puppet and facter on the agent node. [root@rhel6 ~]# yum install puppet facter Once these packages are installed on both the machines. Make sure that your agent node can ping the server node with the name as puppet. [root@rhel6 ~]# ping puppet PING puppet (192.168.122.14) 56(84) bytes of data. 64 bytes fr...

*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     ├──...

*Resources in Puppet "puppet resource"* Understanding Resources is fundamental to understanding how Puppet works. Resources are like building blocks. They can be combined to model the expected state of the systems you manage.  For more information about the resources in puppet you can fire "puppet resource -h" on CLI. This command transforms the current system state into puppet code also it has the ability to modify the current state of the system. Syntax: resource_type { 'resource_name'   attribute => value   ... } Below are the few examples: To see all the users in the machine. [root@puppet ~]# puppet resource user  To see a particular user in the machine.   [root@puppet ~]# puppet resource user sunny user { 'sunny':   ensure           => 'present',   comment          => 'Sunny_B',   gid     ...