APT Plugin for Check MK

We are using Check_MK for monitoring at work. It features a quite nice replacement for NRPE agents and automatic Nagios configuration generation.

I wrote an APT Plugin which will refresh the package cache on every agent, every 60 minutes and check for new Debian upgrades or security updates. Depending on the severity it will return different Nagios status codes:

its hosted at GitHub.

Agent installation

Install the python-apt package and copy plugins/apt to your servers. You would properly want to add this to puppet.

  aptitude install python-apt
  git clone git://github.com/sts/checkmk-apt.git
  checkmk-apt/plugins/apt /usr/lib/check_mk_agent/plugins/apt
  chmod a+x /usr/lib/check_mk_agent/plugins/apt

Installing on your Nagios Server

Copy checks/apt to your checks directory and run a Check MK inventarize and config update.

  git clone git://github.com/sts/checkmk-apt.git
  cp  checkmk-apt/checks/apt /usr/local/share/check_mk/scripts/
  chmod a+x /usr/local/share/check_mk/scripts/apt

  # Check_MK Inventory+Generate Nagios Configuration
  check_mk -I alltcp
  check_mk -U
  invoke-rc.d nagios3 restart

Puppet + Passenger

Puppet is a configuration management tool, its been under heavy development for almost five years now. It became a major open source project in the last few years, surrounded by a large community.

In most of the current environments Puppet Masters will either run on webrick or for the larger environments mongrel was quite standard for a while now.

But Puppet is as well able to be run from within Apache or Nginx. Then you would be using mod_rails (aka. Phusion Passenger). This solution is known to scale best, but was always a bit bulky to install.

puppet-passenger-diagram

Debian's Puppet package maintainers have prepared the puppetmaster package in Squeeze for an easy installation with mod_rails, so I think this could get the new standard way to install the puppet server.

Rescently the Debian project announced the freeze on its testing branch (codename "Squeeze") which in consequence means that: no more new features will be added and all work will be consentrated on polishing testing up to production level.

I thought it to be a good time then to prepare the "Squeeze" upgrade of my puppet servers and write a short article about it.

Install the packages:

  aptitude install puppetmaster libapache2-mod-passenger

Enable the Apache Modules:

  a2enmod headers
  a2enmod ssl

Manually change config.ru

Update: Meanwhile you can skip this step.

I had to manually fix the Rackup-file which comes with the squeeze puppetmaster package. This file contains logic for initializing puppetmaster as a rack application. It still tries to initialize puppetmaster, although the puppet server component was renamed to master.
There is already a open Debian bug for this, and should get fixed until the final release.

See bug #593557

Now change /usr/share/puppet/rack/puppetmasterd/config.ru to:

  # a config.ru, for use with every rack-compatible webserver.
  # SSL needs to be handled outside this, though.
  
  # if puppet is not in your RUBYLIB:
  # $:.unshift('/opt/puppet/lib')
  
  $0 = "puppetmasterd"
  require 'puppet'
  
  # if you want debugging:
  # ARGV << "--debug"
  
  ARGV << "--rack"
  require 'puppet/application/master'
  # we're usually running inside a Rack::Builder.new {} block,
  # therefore we need to call run *here*.
  run Puppet::Application[:master].run

Configure Puppet

When you lounch Puppet the first time, it will generate the SSL certificates. Make sure you configured the puppet certname option to fit your hostname.

If puppetmaster started before you configured it, you can simply delete the ssl directory (/var/lib/puppet/ssl) and restart the puppet master. It will regenerate the directory automatically.

The following represents my puppet configuration in /etc/puppet/puppet.conf.

  [main]
  logdir=/var/log/puppet
  vardir=/var/lib/puppet
  ssldir=/var/lib/puppet/ssl
  rundir=/var/run/puppet
  factpath=$vardir/lib/facter
  templatedir=$confdir/templates
  
  [master]
  certname=puppet.ono.at
  ssl_client_header=SSL_CLIENT_S_DN
  ssl_client_verify_header=SSL_CLIENT_VERIFY      

  [agent]
  server=puppet.ono.at

  [cert]
  autosign=false

After the certificates are generated, you should disable the puppetmaster daemon in /etc/default/puppetmaster by setting $START from yes to no.

Apache Configuration

Finally configure an Apache virtual host to listen on port 8140 and point it to the ssl certificates generated by puppet. Put the following configuration in /etc/apache2/sites-available/puppetmaster:

  ## Puppetmaster Apache Vhost Configuration
  
  ## Passenger Limits
  PassengerHighPerformance   on
  PassengerMaxPoolSize       12
  PassengerPoolIdleTime    1500
  # PassengerMaxRequests   1000
  PassengerStatThrottleRate 120
  RackAutoDetect            Off
  RailsAutoDetect           Off
  
  Listen 8140
  
  
     ServerName puppet.ono.at
  
     SSLEngine on
     SSLCipherSuite SSLv2:-LOW:-EXPORT:RC4+RSA
  
     SSLCertificateFile      /var/lib/puppet/ssl/certs/puppet.ono.at.pem
     SSLCertificateKeyFile   /var/lib/puppet/ssl/private_keys/puppet.ono.at.pem
     SSLCertificateChainFile /var/lib/puppet/ssl/ca/ca_crt.pem
     SSLCACertificateFile    /var/lib/puppet/ssl/ca/ca_crt.pem
  
     ## CRL checking should be enabled; if you have problems with
     ## Apache complaining about the CRL, disable the next line
     SSLCARevocationFile     /var/lib/puppet/ssl/ca/ca_crl.pem
     SSLVerifyClient         optional
     SSLVerifyDepth          1
     SSLOptions              +StdEnvVars
  
     ## The following client headers allow the same configuration
     ## to work with Pound.
     RequestHeader set X-SSL-Subject %{SSL_CLIENT_S_DN}e
     RequestHeader set X-Client-DN %{SSL_CLIENT_S_DN}e
     RequestHeader set X-Client-Verify %{SSL_CLIENT_VERIFY}e
  
     RackAutoDetect On
  
     DocumentRoot /usr/share/puppet/rack/puppetmasterd/public
  
     
         Options None
         AllowOverride None
         Order allow,deny
         allow from all

Now enable the virtual host configuration, enable all required modules and restart the Apache daemon:

  a2ensite puppetmaster
  a2enmod header
  a2enmode passenger
  apache2ctl configtest
  apache2ctl restart

Final Step - Test

After everything is in place, please test your setup. Open up a web browser and point it to the following Url [adapt the hostname]:

https://puppet.ono.at:8140

You should see a line stating:

"The environment must be purely alphanumeric, not ''"

Happy Birthday!

I was a bit surprised when I opened my inbox today. Today is my birthday, but today is also Debian's Birthday!

thank.debian.net
Happy Birthday Debian!

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