Puppet Administration [In progress]

 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...

Here we will try to create a module[sudo] and see how we can use it. For more information about the structure of a module you can check this link . Our mission is to add users sunny and bbee to the sudoers file. Firstly create a directory called sudo in /etc/puppet/modules/ directory. This is basically your module name. [root@puppet modules]# mkdir sudo Now create three sub-directories in it as manifests, files, templates. [root@puppet modules]# mkdir manifests files templates So your current structure is somewhat like this: sudo/ ├── files ├── manifests └── templates 3 directories, 0 files The first and foremost part is to check and install[If not installed] the necessary package. package { 'sudo':                 ensure => present,                 } The above code states that package sudo should be installed in ...

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:2...

*Describe sub-command in Puppet "puppet describe" * The puppet describe sub-command can list info about the currently installed resource types on a given machine. This is a built in documentation and a great source of information. It helps us to know the behavior of types, their properties and parameters. "puppet describe -l" — List all of the resource types available on the system. "puppet describe -s <TYPE>" Print short information about a type, without describing every attribute "puppet describe <TYPE>" Shows each and every information about the type which you are referring too. [root@puppet ~]# puppet describe -l 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 a...

*Apply sub-command in Puppet "puppet apply"* This is the standalone puppet execution tool which is used to apply individual manifests. It is an application that complies and manages configuration on node. Point to note is puppet apply never runs as a daemon like puppet agent. It always runs like a single process which complies a catalog then applies it send a report that's it. Most important option with puppet apply command is modulepath. Suppose you are firing puppet apply XYZ.pp file then it will take the module location as /etc/puppet/modules by default but if in case your modules are there in some other directory suppose /root/puppet-modules then you can use "modulepath" with this location to ask puppet to use it. Running a puppet apply command to apply the changes to the machine with site.pp manifest. [root@puppet manifests]# puppet apply site.pp notice: /Stage[main]/Sudo/File[/etc/sudoers]/content: content changed '{md5}e81452ad78198a...

*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     ...

Puppet is an open source configuration management utility. It runs on mostly all Unix/Linux flavors as well as on Microsoft Windows, and includes its own declarative language to describe system configuration. With Puppet, repetitive tasks are automated away, so sysadmins can quickly deploy business applications, scaling easily from tens of servers to thousands, both on-premise and in the cloud. Puppet is written in a declarative language, means you tell Puppet what results you want, rather than how to get there. Puppet is produced by Puppet Labs, founded by Luke Kanies in 2005. It is written in Ruby and released as free software under the GPL. Most of Puppet’s functionality comes from a single puppet command, which has many sub-commands. Most importantly there is a sub-command called resource. The resource subcommand can inspect and modify resources interactively. [root@server manifests]# puppet resource service service { 'NetworkManager':   ensure => 'r...