Augeas

A simple idea  => A powerful tool

AUGE...wHAaaaT ?

wHAT DOES IT SOLVE (1/2)

         Change the port sshd is listening on


 sed -i 's/^Port .*/Port 2222/g' /etc/ssh/sshd_config

         Edit if exists, else append

awk '/^vm.swappiness/ {print "replacement"; found=1} !/^vm.swappiness/ {print $0} END {if (!found) {print "appended" }}' filename

What does it Solve (2/2)

define host{
  host_name DROVER
  use Servers-Linux
  alias DROVER
  address 1.2.3.4
  hostgroups HOME_OFFICE,IN_SCOPE-SERVER,SERVER_GRP,SLA_SERVER_CORE
  check_command check_centreon_ping
  contact_groups SERVER_GRP
  notification_interval 0
  first_notification_delay 5
  notification_period 24x7
  notification_options d,u,r,f
  notifications_enabled 1
} 

awk 'NR % 20 == 9 && // { print window[(NR-7)%7] } { window[NR%7]=$2 }' hosts.cfg

http://www.linuxquestions.org/questions/linux-general-1/parsing-through-a-nagios-config-file-to-extract-info-w-sed-awk-vi-etc-837818/


sED / aWK / gREP OLDER THAN YOU

Grep : 1973

Sed : 1973

Awk : 1974

Puppet : 2005

CFEngine3 : 2008

Chef : 2009

Simply not the right tool for the right job - anymore

tEMPLATES / lINEINFILE

Templates : Remains a model.  Limited flexibility.

Lineinfile (Ansible) :  Primitive.

They both miss the point.

Configuration is not simply text, it is bound to a software logic

aUGEAS pRINCIPLES

Specialize (treeify) a configuration file via lenses

Provide an API to manage the tree

192.168.34.194 blog.devopsmtl.ca 

/files/etc/hosts
/files/etc/hosts/1
/files/etc/hosts/1/ipaddr = "192.168.34.194"
/files/etc/hosts/1/canonical = "blog.devopsmtl.ca" 

aUGEAS killer features

Specialization of configuration file / Software logic behavior

Real query language (XPath)

Bindings for all common programming language

Currently 179 lenses

Solutions To Previous problems

set /files/etc/ssh/sshd_config/Port 2222 

set /files/etc/resolv.conf/domain devopsmtl.ca 

print /files/etc/nagios/nagios.cfg/host/*[hostgroups = SERVERGRP]/hostname

Where IS DEVOPS in ALL THAT ?

  Basic Pattern : Installation -> Configuration -> Service start

        Installation :  

 yum install pkg

        Service : 

 service serviced start

        Configuration : 99% of the work

Augeas PROVIDERS

    Each bit of configuration file becomes a Puppet ressource

augeas {"add domain" :
    context => '/file/etc/resolv.conf',
    changes => [
        "ins domain before nameserver[1]",
        "set domain devopsmtl.ca",
    ],
    onlyif => "match domain[.='devopsmtl.ca'] size == 0", 
} 

AUGEASPROVIDERS PROVIDERs

nrpe_command { "check_updates":
  ensure  => present,
  command => "/usr/bin/check_updates -w 1 -c 5 --security-only",
}
nrpe_command { "check_ssh":
  ensure => absent,
}

  available AUGEASPROVIDERS

apache_setenv

host

kernel_parameter

mailalias

mounttab

nrpe_command

pg_hba

puppet_auth

shellvar

sshd_config

sshd_config_subsystem

Conclusion

brain { 'new state of mind' :
    sed       => absent,
    grep      => absent,
    awk       => absent,
    templates => occasionally,
    augeas    => installed,
}  

Questions ?