Again this is a late blog post about some code committed several months ago, in this case the code was committed 09/06/2009

It is a very short python script to force a subversion commit message to be greater than 10 characters in length

Installation:

svn export https://svn.blog.oneiroi.co.uk/branches/python/svn_force_message.py /path/to/your/svn/hooks/pre-commit chmod +x /path/to/your/svn/hooks/pre-commit

Note installation this way will replace your current pre-commit hooks file.

Pre-req reading:

Nagios customization: Alerting via SMS, or anything you like!

Making the bird tweet using python or Update twitter in a single line

This entry will cover how to send nagios alerts to twitter, in the examples to follow curl will be used however you can choose to use the python example (link above) in place of this.

Firstly edit /usr/local/nagios/etc/objects/commands.cfg

And add the two following commands.

UPDATE 24/03/2011 Twitter no longer supports basic auth, use my oAuth updater here

define command {
        command_name    notify-by-twitter
        command_line    /usr/bin/curl --basic --user "twitteruser:twitterpassword" --data-ascii "status=[Nagios] $NOTIFICATIONTYPE$ $HOSTALIAS$/$SERVICEDESC$ is $SERVICESTATE$" https://twitter.com/statuses/update.json
}

define command {
        command_name    host-notify-by-twitter
        command_line    /usr/bin/curl --basic --user "twitteruser:twitterpassword" --data-ascii "status=[Nagios] $HOSTSTATE$ alert for $HOSTNAME$" https://twitter.com/statuses/update.json
}

Now define a contact for this twitter service

/usr/local/nagios/etc/objects/contacts.cfg

define contact{
        contact_name                    twitter
        service_notification_commands   notify-by-twitter
        host_notification_commands      host-notify-by-twitter
        service_notification_period 24x7
        host_notification_period 24x7
        service_notification_options a
        host_notification_options a
}

Choose your own notification options, for my feed I only choose alerts, I also have this send updated to a ‘private feed’ which I then follow.

Add this contact into your existing contact groups, i.e.

define contactgroup{
        contactgroup_name       admins
        alias                   Nagios Administrators
        members                 nagiosadmin,sms_alert,twitter
        }

Then run a nagios-verify to ensure you have no syntax errors, and restart nagios.

Trigger an alert by manually switching a monitored service off or entering a manual result to test.

Some two months after the fact, I thought it may well be time to post a blog on this little code snippet.

As some of you have noticed every commit message to my subversion repository is infact updating my twitter.

This code was uploaded to subversion on 10/06/2009, so sorry for the late write up! Requirements

Python 2.5 or higher Subversion server

Installation

• svn co https://svn.blog.oneiroi.co.uk/branches/python/svn_tweeter.py /usr/bin/svn_tweeter
• chmod +x /usr/bin/svn_tweeter
• cd /path/to/svn/hooks
• Edit post-commit with your favorite text editor

REPOS="$1"
REV="$2"

/usr/bin/python /usr/bin/svn_tweeter -u twitterusername -p twitterpassword -r $REV -s $REPOS

Now try a commit, and check your syslog for entries from the script.

Aug 24 11:36:26 132 python: SVN_TWEETER: https://twitter.com/statuses/update.json query complete

UPDATE 24/03/2011 Twitter has removed basic authentication, you must use oauth (admittedly it has been like this for a fair while now) use this nagios_bot instead

We are still unfortunately waiting for the memory to arrive from crucial, sigh, so in this part I will cover what the “extras” are and the installation of them.

Parts list:

1. Chenbro ES34069
2. Jetway JNC92 Motherboard
3. Jetway SATA II Daughterboard
4. 2GB Transcend Flash Memory Module
5. 4 x Samsung Spinpoint 1TB
6. 2GB Low profile Ram (When it arrives)

The Case

The Chenbro ES34069 case has 4 ‘hot swappable’ SATA 2 HD caddies, optional card reader, internal PSU.

PROS:

Good quite case, has all the required features, even some extras such as LED’s for the network interfaces, nice and compact, with the hot swap being a major bonus

CONS:

I’d have to say the price, this case weighs in at £200+ which is a bit hefty for a case.

The proprietary PSU adapter, I’ve not had any issues with the PSU’s power adapter, but by the looks of things it is bespoke to Chenbro, so I doubt getting a spare/replacement is going to be easy.

The USB header, and optional Card reader, this is more a ‘con’ of this build, as the motherboard used only has 2 USB headers, one of which is being used by the USB storage for the operating system, meaning you have the choice of either using the front facing USB or the optional card reader.

Inaccessible backplane, now this for me was the kicker, the Daughterboard comes with some finely crafted 90 degree SATA cables, which would of been perfect, if I had been able to actually access the backplane to attach them, I could not for the life of me find a way to get to the backplane without causing irreversible damage to the case itself.

The Motherboard

The Jetway JNC92 Motherboard comes with an Intel Atom Dual core 330 processor, the reasoning behind this will become clear later on, however you can opt for the cheaper single core processors if you wish.

As the picture shows I have opted to use a Transcend 2GB USB module which attaches directly onto the motherboard, this will be used to store the freeNAS operating system

The SATA II Daughterboard has onboard hardware RAID support 0, 1, 0+1, and 5 RAID options across the 4 ports, I am still debating using the hardware RAID over Software RAID for the following reasons.

Yes I know Hardware raid is much much faster however as I understand it due to the XOR logic used in the hardware processor, using hardware raid essentially locks you into using a particular manufacturers hardware, which if this line is discontinued by the time something goes wrong is a serious issue when trying to recover data, this is where software raid shines as it is code based, and will run from any x86 capable hardware, and lets face it, it is not as if we are lacking CPU power in this build!

PROS:

Cheap and cheerfull motherboard

Powerful dual core CPU (Not like we’re going to be playing Crysis here, but for the use it is intended this CPU has ample power)

Expandability, this HAS to be the biggest selling point for this motherboard, you do not have to use it for any one thing in particular, I will shortly be looking at using this motherboard with the 3 x Gigabit daughterboard for building a hardware network monitor, think IDS, man in the middle machine goodness!

CONS:

Heatsinks, or their rotation they are top to bottom, where as the case I am using as most cases now has the airflow front to back, this is a minor con, but the heatsinks should be orientated for the best airflow.

USB headers, the Transcend USB module is designed to lock into the plastic socket you useually find on your USB headers, this motherboard does not have the sockets just the raw pins.

More images

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As the company I am working for (Psycle Interactive Ltd) grow there became an increasing need to store and share large files between machines, granted we are all on MACs here, but the “drop box” becomes inconvenient when you want to share that file with multiple people.

As such I looked for ways to build a “cost effective” NAS, and now following the success of a recent build using FreeNAS for deploying an office NAS with 2.7TB of usable disk space I/we have developed a concept for using these relatively cheap NAS systems for Disaster Recovery Purposes.

This NAS build at the time of writing costs £740.54 inc VAT, for a 4TB system, giving approx 2.7TB of usable diskspace in a RAID 5 configuration, try getting a pre-built model for that, here’s a comparison

• 4TB NAS Built in this series £740.54 inc VAT
• Iomega 4TB NAS ~£2576.50
• HP Proliant 4TB ~£4502
• Netgear Readynas ~£1322.17

note: “~” As show above I will be building our 4 NAS systems (1 I have already built) for around £1600 less than the price of a single HP Proliant system.

This blog series will cover the build process of the NAS systems as they are built, along with the theory and methods used to allow them to function as DR devices.

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Currently we are waiting for the memory to arrive from Crucial, so until that arrives the new builds will not progress, in Part 2 I will be going over the motherboard and the “extras” we have chosen to use for this build.

See you in part 2!