Check LUN Ownership on the EMC VNX Array RUBY + Naviseccli

Daily Puppet - Virtual Resources

Virtual Resources are used when there is a need to have the same resource part of many classes.

Lets look at an example.

We have a user named "terry", who has to be part of two classes

1. test --> a very generic module for Ubuntu
2. testsql --> Another very generic module :), but applied to a different OS, CentOS

So, we define it first,



This we will insert in two modules(manifests), test and testsql




We have assigned "test" module assigned to centos server named centosserver, and "testsql" module assigned to a Ubuntu system named sqlserver1.



We will run now run the puppet agent on both the systems



Refer to the error message for sqlserver1. It says "Error: Could not retrieve catalog from remote server: Error 400 on SERVER: Evaluation Error: Error while evaluating a Resource Statement, Duplicate declaration:"

To overcome this, we use virtual resources



Look at the declaration, "@" with user, this indicates, the user resource declared is a virtual resource.

Now, we need to Realize the resource in init.pp in modules test and testsql , so that the resource is created on the target systems.



From the snippet it can be seen that, realization is done in two ways,

a) realize (User['terry'])
b) User <|title == 'terry' |>

(Don't forget to include the class test::virtual in both the init.pp files, otherwise, we can not get the resource at all )

Now, we run the puppet agent on the clients again



With virtual resources, we can create user terry on both the systems.

Daily Puppet - Puppet Environment Directories

Puppet environments can help to differentiate between the level of code, like production, staging, development. 

To setup the Directory environments, we need to make some changes to the default puppet.conf file.




Once these changes are applied, we will need to restart the puppet master service. 

We have set the environment folders to be searched in the path “/etc/puppet/environments”, by using the configuration directive,
environmentpath = $confdir/environments


We will now create a staging environment for a test module “mytestmodule”




Our init.pp file is a simple one, which will create a test file.We will assign the module to the node.



Now, we test our environment,

puppet agent --noop --test --server centos  --environment=staging
Info: Retrieving pluginfacts
Info: Retrieving plugin
Info: Caching catalog for centos
Info: Applying configuration version '1424034120'
Notice: /Stage[main]/Mytestmodule/File[/home/testingenv.txt]/ensure: current_value absent, should be present (noop)
Notice: Class[Mytestmodule]: Would have triggered 'refresh' from 1 events
Notice: Stage[main]: Would have triggered 'refresh' from 1 events
Notice: Finished catalog run in 0.03 seconds

This kind of set up is very helpful, when we want to separate our production code from the testing code. 

Daily Puppet 3 - Inheritance

With the inheritance we can set the order in which resources are applied on an agent.

A test manifest is shown below, it is rather simple one.




Here we have defined a class “ownerfile”, which has a resource file “/tmp/owner.txt”. There is another file “/tmp/depenfile”, which will be created after the owners.txt file.


First owner.txt file is created and then depenfile is created.


Another approach is using the “require”



In the above manifest it is shown that,
File resource “/tmp/dependrequire.txt”  defined which requires another resource which is a file resource too, “tmp/owners.txt”
First owners.txt is created as it is required by the file resource dependrequire.txt. Then dependrequire.txt is created.

Daily Puppet -2

It has been a while since I wrote something on this blog(Not that there are people expecting something in here). However, it is mostly for my reference. Puppet is something which I am interested in learning and making amends since sometime to learn it. I did some learning and later dropped it like many other my learning projects.

So, I learnt how to create Users and Home directories.

As usual I have revise the basics.

The resources are manifests, can be a USER, SOFTWARE, SERVICE etc. They have to be defined in the manifests folder of their own for their better manageability.

/etc/puppet/modules

root@ubuntu:/etc/puppet/modules# ls -l

drwxr-xr-x 3 root root 4096 Jun 9 19:25 homedirs

drwxr-xr-x 3 root root 4096 Jun 9 19:25 users

As shown in the above snippet, two modules have been created.

Each of this module folders will have a manifest folder within it

A very good demo is here,

http://theruddyduck.typepad.com/theruddyduck/2013/11/using-puppet-to-configure-users-groups-and-passwords-for-cloudera-manager.html

this blog has wonderful crisp explanation

Let us examine on init.pp file

root@ubuntu:/etc/puppet/modules/users/manifests# pwd

/etc/puppet/modules/users/manifests

cat init.pp

class users {

group {'edinhazard':

ensure => present,

}

user {'edinhazard':

ensure => present,

gid => 'edinhazard',

shell => '/bin/bash',

home => '/home/edinhazard',

managehome => 'true',

password => '$1$CcKAjalB$nUN4y42rmL5ptKs6413Id0',

}

}

this init.pp file first defines a class called “users”

within the class “users”, we define objects that can be assigned to a user.

Next we look at another module which is “homedirs”.

root@ubuntu:/etc/puppet/modules/homedirs# cat manifests/init.pp

class homedirs {

file{"/home/edinhazard":

ensure => "directory",

owner => "edinhazard",

group => "edinhazard",

}

}

here we are making sure the home directory created for user 'edinhazard' has the right permissions.

Once defining these how do we call them to be installed on the nodes?

there is a file in the “/etc/puppet/manifests” folder named 'nodes.pp'. Assign the modules to the node 'desktop' as shown below.

root@ubuntu:/etc/puppet/manifests# cat nodes.pp

node 'desktop' {

include users

include homedirs

}

Now we apply the configuration on the client, i.e., “desktop”

From the CLIENT Node, we run puppet agent --test

puppet agent --test

Info: Retrieving plugin

Info: Caching catalog for desktop.home

Info: Applying configuration version '1402368999'

Notice: /Stage[main]/Users/Group[edinhazard]/ensure: created

Notice: /Stage[main]/Users/User[edinhazard]/ensure: created

Notice: Finished catalog run in 0.71 seconds

Lets now see, if the desired user has been created,

cat /etc/passwd | grep edin

edinhazard:x:1001:1001::/home/edinhazard:/bin/bash

root@desktop:/home# ls -l | grep edin

drwxr-xr-x 2 edinhazard edinhazard 4096 Jun 22 11:59 edinhazard

So, puppet did what has been asked to do. This is a simple configuration applied

Syntax reference

http://www.puppetcookbook.com/posts/create-home-directory-for-managed-users.html 

Daily Puppet - 1

Puppet is an open source framework and toolset for managing the configuration of computer systems.

From sometime, I wanted to learn some tricks on Puppet.This weekend I finally made up my mind and did some very basic stuff with puppet

My goal was to push a file resource from the puppet server to the client. I used the Ubuntu 12.04 machines for testing. If one doesn’t want to install the whole thing then, pre-configured VM can be downloaded from http://info.puppetlabs.com/download-learning-puppet-VM.html

So, lets start.

Installing Puppet master on Linux

aptitude install puppetmaster

Installing Puppet client

aptitude install puppet

Connecting the Puppet Client to the Server

puppet cert –sign “desktop”

We have to sign the client

puppet cert –sign “desktop”

Output :

notice: Signed certificate request for my-desktop

notice: Removing file Puppet::SSL::CertificateRequest my-desktop at ‘/var/lib/puppet/ssl/ca/requ

Creating the First Manifest

On the server move to folder /etc/puppet/manifests, create a “node.pp” file,

gedit nodes.pp


node ‘my-desktop’ {

                               file { “/tmp/hello.txt”:

                              content => “Hello, My First Manifest”,

                             }

}

Create “site.pp” in the same folder

gedit sites.pp

import ‘nodes.pp’

$puppetserver = ‘ubuntu.home’

From the client run the command

puppet agent –test

Output :

info: Caching catalog for my-desktop

info: Applying configuration version ’1370675206′

notice: Finished catalog run in 0.03 seconds

After this when we check the /tmp/ folder , we can see the file is in tmp folder on the client.

What Just happened ?

I am a beginner on the puppet. My Explanations may not be right, but these are my observations.

We installed a Puppet Master server

We installed a Puppet client

Added the client to the Puppet Masters visibility,i.e. server-client interaction

Created first Manifest. A “Manifest” is a puppet’s way of telling the configuration information to the client.Example :

If we see the nodes.pp file, there is a Resource, which a “File Resource”, called “hello.txt” defined for a client “my-desktop with the content “Hello, My first Manifest ”. A resource should be applied to the client when client requests it. This can be a package or file etc. (this case it is a file).

When puppet client contacts the server for the resource, it will get the file in its “tmp ” folder. (Resource is “/tmp/hello.txt”)

So for now, this just a beginning of my date with Puppet.

Logical Volume Management - Extending root file system online in Linux

Situation : 

On a Linux server, the root file system got full, as it was running some application which is prone to create large number of files. 

If Linux system Partitioning is LVM based then it is very easy. 

Few checks before will certainly help. 

Determine the Volume Group you want to extend and see if the mount point exists on the logical volume belongs to the VG you are extending.  

Steps : 

• Create a Physical volume 
• Add it to the Volume Group, aka, VG
• Extend the logical volume
• Re-size the file system online

Example : 

Physical volume creation 

            pvcreate /dev/sdb

Adding it to the Volume Group 

            vgextend vg_livedvd /dev/sdb

Extending the Logical volume 

            lvextend -L +30G  /dev/vg_livedvd/LogVol00

Re-size the file system online 

            resize2fs /dev/mapper/vg_livedvd-LogVol00