Category: Linux

Centralised Logging

I’m currently looking at some centralised logging tools and the following stand out:

  • Octopussy – one I cam across a long time ago but looking at some of the others below it may be past its sell by date?
  • Graylog2 – GSOH (in dating parlance) – “Manage your logs in the dark and have lasers going and make it look like you’re from space.“
  • logstash – “a tool for managing events and logs. You can use it to collect logs, parse them, and store them for later use (like, for searching). Speaking of searching, logstash comes with a web interface for searching and drilling into all of your logs.“
  • Kibana - You have logs. Billions of lines of data. You shipped, dated it, parsed it and stored it. Now what do you do with it? Now you make sense of it… Kibana is an alternative browser based interface for Logstash… that allows you to efficiently search, graph, analyze and otherwise make sense of a mountain of logs.

Kibana has a Bootstrap UI and is written in PHP which immediately bumps it up my list 😉

Ubuntu 12.04 (Precise Pangolin) and PHP 5.4 (again)

My previous post, Ubuntu 12.04 (Precise Pangolin) and PHP 5.4, has been extremely popular but I left some work for the user to figure out.

In a nutshell, here is how you install PHP 5.4 in Ubuntu 12.04 (Precise Pangolin).

1. Install the signing key for the PPA (which also adds the sources to apt):

add-apt-repository ppa:ondrej/php5

If the above command is not available, install it using:

apt-get install python-software-properties

2. Now update the package database and then upgrade the system. As part of upgrading, PHP 5.4 will be installed automatically:

apt-get update
apt-get upgrade
apt-get dist-upgrade

Now, you should have PHP 5.4 installed:

# php -v
PHP 5.4.3-4~precise+1 (cli) (built: May 17 2012 13:00:25)
Copyright (c) 1997-2012 The PHP Group
Zend Engine v2.4.0, Copyright (c) 1998-2012 Zend Technologies

As an aside, at the time of my previous post, PHP Memcache packages were not available from the PPA but that has since been rectified.

Ubuntu 12.04 (Precise Pangolin) and PHP 5.4

UPDATED in Ubuntu 12.04 (Precise Pangolin) and PHP 5.4 (again) (May 22nd 2012).

I was looking forward to trying out some of the new features in PHP 5.4 when I upgraded to Ubuntu 12.04 this morning. Unfortunately, Ubuntu decided to stick with 5.3 for this release.

There is upgrade path available though via a PPA (Personal Package Archive) from Ondřej Surý at https://launchpad.net/~ondrej/+archive/php5.

I’ve just installed it and it’s working fine with Apache:

$ php -v
PHP 5.4.0-3~precise+4 (cli) (built: Mar 27 2012 08:50:50)
Copyright (c) 1997-2012 The PHP Group
Zend Engine v2.4.0, Copyright (c) 1998-2012 Zend Technologies

 

New Replication Features in MySQL 5.6

I’ve just been reading an article on replication in MySQL 5.6 and there are quite a few new cool features that will vastly improve replication environments with MySQL. Some of these include:

  • Optimised row based replication (documentation here) – replication used to mean execute the exact same queries on the slave server(s) as the master. This, as you can imagine, was incredibly inefficient. With row based replication, the resultant changed row of an INSERT, UPDATE or DELETE operation was replicated saving significant resources on slave servers. This was a big win. It now looks like it’s been further optimised in that only the changed elements (and a primary key) need to be replicated.
  • Introduction of Global Transaction Identifiers (GTIDs) allowing the source and sequence of a replication statement to be globally unique within a replication cluster. This with some cool new utilities (mysqlfailover and mysqlrpladmin) create a lot of native options for failover for maintenance or failure (see more about GTIDs and the utilities).
  • Time delayed replication allowing a slave to purposefully remain behind the master for any given delay. This may be a life saver for that table you accidently dropped!

There’s a lot more too and you can read about it all here.

Looking at New Features in PHP 5.4

PHP 5.4 was released at the start of March and heralds a key new feature which I have long bemoaned the lack of: traits.

Traits (see PHP’s documentation and Wikipedia’s description) allow programmers to define a set of functions which can be shared among different classes in ways that normal inheritance cannot do.

A Trait is intended to reduce some limitations of single inheritance by enabling a developer to reuse sets of methods freely in several independent classes living in different class hierarchies.

I’ve banged my head against the desk a number of times trying to work around the lack of traits in PHP and I hope PHP 5.4 makes its way into mainstream Linux distributions a lot quicker that 5.3 did.

There are also a number of other interesting features which look really cool:

  • Simpler array dereferencing: $secondElement = getArray()[1];
  • A shortened array syntax: $a = [ "foo" => "bar", "bar" => "foo" ];
  • A built in web server (for development) which could be really interesting – see here.

 

TallyStick, ViMbAdmin and a CSS/JS Minify Tool

It’s been a busy few weeks:

  • We launched TallyStick – a time tracking and billing tool – two weeks ago and have pushed some bug fixes and updates. So far so good!
  • IXP Manager, an open source web application to assist in the management of Internet Exchange Points (IXPs) that we built over at INEX, got a complete UI refresh thanks to Twitter’s Bootstrap;
  • Similarly, our open source email domain / mailbox / alias management tool called ViMbAdmin got a major version bump, lots of new features and a UI refresh also;
  • We also just open sourced (BSD) our (admittedly small) Minify tool which makes minifying, bundling and versioning the manner JS and CSS files that make up websites these days a breeze. Check it out on GitHub: https://github.com/opensolutions/Minify.

“Go Faster” Websites – Introducing Minify

We’ve been minifying and bundling CSS and JS for years to ensure quick page loads of the applications we build. We’ve now generalised, documented and packaged the tool we use for this and released it under a BSD license so others can benefit.

Most web developers know that including lots of JS and CSS files in their sites slow page load times down. Most also know that these files should be minified and bundled into one file on production sites. Most developers don’t do this though. It’s a lot of extra steps in putting your new changes live.

Also, using CDNs or setting expiry times into the future for mostly static files such as CSS and JS also significantly improves page load as clients will grab these files once and use their local cache until their expire. This also poses issues for web developers that is easily overcome by versioning these files – literally adding a version number to the bundles – for example min.bundle-v6.css would be version 6 of the CSS minified and bundled file.

We’ve been doing both of these for a long time with the sites we build. We’ve now generalised, documented and packaged the tool we use for this and released it under a BSD license so others can benefit. See our page on GitHub to download this tool and for examples of its use:

https://github.com/opensolutions/Minify

This tool will:

  • automatically find all CSS/JS files in a given directory named xxx-blah.css where xxx is a three digit ordering / sequence number;
  • minify these files and create a single file bundle including them in the correct order;
  • automatically generate template include files allowing production / development mode (i.e. use individual CSS/JS or bundles based on an application option);
  • versioning for those using CDNs, future expiry dates, etc to ensure clients load fresh JS/CSS bundles.

If you use it, please drop us a note to let us know how you get on! 

Look What We Just Made: TallyStick

[TallyStick Logo]
Are you like I once was with scribbles in your diary to track what you were doing for whom and for how long on any given day? When you manage to remember to scribble that is.

I was once a member of your club. And I had enough. So we built TallyStick. Necessity, as the saying goes, is the mother of invention.

At Open Solutions, we manage networks, build Internet infrastructure, consult and develop web applications for many customers. Tracking the time our engineers spent on different projects – especially those on the front line hopping from customer to customer – was becoming an issue.

We believe in web applications that are simple, beautiful and functional. And after an exhaustive search, we couldn’t find one to fit our needs… so we built it. And who better to build a time tracking application for IT and other consulting professionals than those same professionals!

TallyStick allows you to focus on what you love to do while it takes care of tracking and accumulating the time you spend on projects. We believe it’s simple, efficient and quick. And we hope you agree.

As of today, TallyStick is live and open for business. Please sign up, take advantage of the one month’s free trial (with no credit card details required) and tell us what you think.

Also, all users signing up during the beta period will receive a lifetime discount of 10% on that account!

Asterisk with SS7 via Wanpipe, Dahdi and libss7 – with ISUP SAM support

A howto on installing Asterisk with SS7 supported via libss7 on Sangoma hardware along with support for ISUP SAM messages.

After much head banging in bringing up an SS7 link with SAM support, I am documented what worked here.

Firstly, what is SAM support? One end of an SS7 link initialises a new call by sending an Initial Address Message (IAM). All SS7 software stacks support this and usually it’s enough. One case where it’s not enough is when one wants to address a phone number with more than the E.164 standard max length of 16  (usually to pass additional information tacked on the start, end of or even replacing an A or B number). In this scenario, SS7 uses a Subsequent Address Message (SAM) to send the additional digits. Most / all mainstream Asterisk SS7 software stacks do not support this.

The platform and software used is as follows:

  • Ubuntu 10.04 LTS standard CLI install;
  • dahdi-linux-complete-2.4.0 from the archives (direct link);
  • a patched version of libss7 supporting SAM via SVN (see below);
  • a patched version of chan-dahdi via SVN (see below);
  • Asterisk 1.6.0.28 from the archives (direct link);
  • Asterisk Addons 1.6.0.6 from the archives (direct link);
  • Sangoma Wanpipe 3.5.24 (direct link).

Yes, I know some of the above are obsolete. Unfortunately it’s what’s required for everything to play nicely together. And, guess what, it works!

Before You Start

Ensure you have all the necessary packages for building the packages:

apt-get install build-essential libnewt-dev subversion    \
   libsqlite3-dev libsnmp-dev bison libtool flex          \
   autoconf2.13 libmysqlclient-dev

You can assume the working directory is /usr/local/src in the following.

Installing dahdi-linux-complete

Download and extract dahdi-linux-complete into /usr/local/src. Then, in the same directory, create some symbolic links:

ln -s dahdi-linux-complete-2.4.0+2.4.0/linux dahdi-linux
ln -s dahdi-linux-complete-2.4.0+2.4.0/tools dahdi-tools

Now build dahdi-linux:

cd dahdi-linux
make
make install

Now move onto dahdi-tools:

cd dahdi-tools
./configure
make menuconfig # (and select tools or accept defaults)
make
make install
make config

Installing libss7

There is a patched version of Digium’s libss7 referred to as Attila’s libss7 available via SVN. Download and install it:

svn co https://observer.router.hu/repos_pub/libss7/trunk alibss7
cd alibss7
make
make install

Installing Asterisk

Download and extract the Asterisk 1.6.0.28 package reference above.

cd asterisk-1.6.0.28

Now this next bit is very important and easy to miss – you also need a patched version of chan_dahdi.c that is compatible with the patched version of libss7. This is also available from SVN:

svn co https://observer.router.hu/repos_pub/chan_dahdi/trunk achan_dahdi

Then copy it to your Asterisk source:

cp achan_dahdi/chan_dahdi.c asterisk-1.6.0.28/channels/chan_dahdi.c

Now continue with the Asterisk installation:

./configure
make menuconfig
make
make install
make samples
make config

Install Asterisk Addons (optional)

Download and unpack the above referenced add ons package and build and install:

cd asterisk-addons-1.6.0.6
./configure
make menuconfig
make
make install
make samples

Sangoma Wanpipe

I’m using one of Sangoma’s E1 / T1 interface cards and so I need Wanpipe also. I’m using version 3.5.24 and preceed as follows after unpacking:

cd wanpipe-3.5.24./Setup install

During the install, follow these prompts:

  • select option 2 => Asterisk/Dahdi Support;
  • enter path /usr/local/src/dahdi-linux (for Zaptel path prompt);
  • select defaults for everything else;
  • you DO want to install start-up scripts;
  • you DO to configure wanpipe devices for DAHDI;
  • you DO want to generate /etc/asterisk/chan_dahdi.conf and:
    • select E1 / T1 as appropriate;
    • select line framing and encoding;
    • choose clock source;
    • select Zaptel/Dahdi – PRI CPE as signalling;
    • select National ISDN 2 as switch type;
    • do not enable hardware DTMF detection;
    • use all channels;
    • select dial plan context as appropriate;
  • and continue for other ports as necessary;
  • finally, choose Save cfg: Stop Asterisk & Wanpipe now
  • you would like wanrouter to start on system boot;
  • and you would like to execute ‘dahdi_cfg’ each time wanrouter starts.

Configuration Steps

We now need to set various options in Wanpipe, Dahdi and Asterisk for SS7 as it’s PRI/ISDN by default.

Edit all /etc/wanpipe/wanpipeX.conf files as necessary and change:

 TDMV_DCHAN              = 16

to

TDMV_DCHAN              = 0

Now edit /etc/dahdi/system.conf and change (for example):

span=1,1,0,ccs,hdb3,crc4
bchan=1-15,17-31
echocanceller=mg2,1-15,17-31
hardhdlc=16

to

span=1,1,0,ccs,hdb3,crc4
bchan=2-31
echocanceller=mg2,2-31
mtp2=1

which of course assumes signalling is on channel 1. If you have voice only links, you might need something like:

span=1,0,0,ccs,hdb3,crc4bchan=1-31
echocanceller=mg2,2-31

Lastly, we need to configure Asterisk. Replace lines such as:

;Sangoma A102 port 1 [slot:4 bus:5 span:1]
switchtype=national
context=from-pstn
group=0
echocancel=yes
signalling=pri_cpe
channel =>1-15,17-31

with an appropriate configuration. Mine follows below with some edits and some important notes at the end:

;Sangoma A102 port 1 [slot:4 bus:5 span:1]
switchtype=national
context=from-pstn
group=0
echocancel=yes

signaling=ss7
ss7type=itu
ss7_called_nai=dynamic
ss7_calling_nai=dynamic
ss7_internationalprefix=00
ss7_nationalprefix=0
ss7_subscriberprefix=
ss7_unknownprefix=
linkset=1
pointcode=1
adjpointcode=2
defaultdpc=3
networkindicator=national_spare
cicbeginswith=2
channel=2-31
sigchan=1
  • Set pointcode, adjpointcode and defaultdpc as appropriate;
  • set networkindicator as appropriate and ensure it matches the other end (you can see what you’re being sent and what you’re sending via ss7 debug;
  • cicsbeginwith is normally 1 but the telco on my end are starting at 2 – this was groping in the dark diagnostics and issues such as no audio, CICs not in service when both sides claim they are, etc may point to misaligned CICs;
  • make sure you have configured from-pstn or the appropriate context in yourextensions.conf.

Confirming Your Link Is Up

Now start wanrouter (/etc/init.d/wanrouter start); dahdi (/etc/init.d/dahdi start); and Asterisk (/etc/init.d/asterisk start). You should see your link come up via logs available with the dmesg command. Launch the Asterisk console and check the status of your links:

ast-deg1-1*CLI> ss7 show cics 1
  CIC   DPC  DAHDI        STATE   BLOCKING
    2    3      2         Idle
    3    3      3         Idle
    4    3      4         Idle
    5    3      5         Idle
    6    3      6         Idle
    7    3      7         Idle
    8    3      8         Idle
    9    3      9         Idle
   10    3     10         Idle
   11    3     11         Idle
   12    3     12         Idle
   13    3     13         Idle
   14    3     14         Idle
   15    3     15         Idle
   16    3     16         Idle
   17    3     17         Idle
   18    3     18         Idle
   19    3     19         Idle
   20    3     20         Idle
   21    3     21         Idle
   22    3     22         Idle
   23    3     23         Idle
   24    3     24         Idle
   25    3     25         Idle
   26    3     26         Idle
   27    3     27         Idle
   28    3     28         Idle
   29    3     29         Idle
   30    3     30         Idle
   31    3     31         Idle

You should now be okay to make test calls.

Do You Need Professional Support / Consultancy?

While I will try to respond to comments and questions on this blog, I don’t have the time to provide one on one assistance pro-bono. Professional consultancy on Asterisk and SS7 is available worldwide through my company, Open Solutions with contact details here.

References

For posterity, I have added Domjan Attila patched libss7 and chan_dahdi to GitHub:

Some New Nagios Plugins

Over the past ten years I have left many many new and hacked Nagios plugins on many servers around the globe. I’m now making a concerted effort to find them, clean them, maintain them centrally and release them.

To that end, I have created a repository on GitHub for the task with a detailed readme file:

As a starting point, there are four plugins available now:

  • check_chassis_cisco.pl – a script to poll a Cisco switch or router and check if the device was recently rebooted; its temperature sensors; its fans; its PSU; its CPU utilisation; and its memory usage.

 

  • check_chassis_server.pl – a script to poll a Linux / BSD server and check its load average; memory and swap usage; and if it has been recently rebooted.

 

  • check_portsecurity.pl – a script to check all ports on a Cisco switch and issues a critical alert if port security has been triggered resulting in a shutdown port on the device.

 

  • check_portstatus.pl – a script which will issue warnings if the port status on any Ethernet (by default) port on a Cisco switch has changed within the last hour (by default). I.e. a port up or a port down event.