Nov 04 2010

High Availability MySQL Cookbook , the review

When I read on the internetz that Alex Davies was about the publish a Packt book on MySQL HA I pinged my contacts at Packt and suggested that I'd review the book .

I've ran into Alex at some UKUUG conferences before and he's got a solid background on MySQL Cluster and other HA alternatives so I was looking forward to reading the book.

Alex starts of with a couple of indepth chapters on MySQL Cluster, he does mention that it's not a fit for all problems, but I'd hoped he did it a bit more prominently ... an upfront chapter outlining the different approaches and when which approach is a match could have been better. The avid reader now might be 80 pages into MySQL cluster before he realizes it's not going to be a match for his problem.

I really loved the part where Alex correcly mentions that you should probably be using Puppet or so to manage the config files of your environment, rather than scp them around your different boxes ..

Alex then goes on to describe setting up MySQL replication and Multi Master replication with the different approaches one can take here, he gives some nice tips on using LVM to reduce the downtime of your MySQL when having to transfer the dataset of an already existing MySQL setup, good stuff.

He then goes on to describe MySQL with shared storage ... if you only mount your redundant sandisk once on your MySQL nodes my preference would probably be a Pacemaker stack rather than a RedHat Cluster based setup, but his setup seems to work too. Alex quickly touches on using GFS to have your data disk mounted simultaneously on both nodes (keep in mind with only 1 active MySQLd) and then goes on to describe a full DRBD based MySQL HA setup

The last chapter titled Performance tuning gives some very nice tips on both tuning your regular storage, as your
GFS setup but also the tuning parameters for MySQL Cluster

I was also really happy to see the Appendixes on the basic installation where he advocates the use of Cobbler , Kickstart and LVM ..

One of the better books I read the past couple of years .. certainly the best book from Packt so far , I hope there is more quality stuff coming from that direction !

Nov 03 2010

Bug Zapper

Dear Fedoracommunity,

Over the course of the day I recieved 22^H3 mails from your friendly Bug Zapper.

Most of those bugs where bugs I had reported upon crashes using bug-buddy. Bugs on different desktop tools such as .. synergy, evolution, gwibber , gnome-settings and probably some others

I do understand that I development goes on and on .. and your fancy devs don't care anymore about bugs I reported on Fedora 12 as they are all hacking on Fedora 15 and that I should update more frequently ...

But what I don't get is that non of these bugs was ever touched,
they've been automatically created , and automatically closed

Luis already told us ages ago .. every project needs a bugmaster apparently Fedora replaced that bugmaster with a Bug Zapper.

So can someone please explain my why I should continue to try to improve Fedora by reporting bugs ?

Nov 01 2010

To Package, and what to package

One of the open sessions last week (corr: last month) at Devopsdays 2010 Hamburg was the one on packaging software. It's always a big question on wether you package the software that runs in your infrastructure or not. And if you package it .. what do you package ..

The general consensus of the open space was pretty much that you always package the software you deploy, unless you have some very good reasons not to. Pretty much the way I've been doing for ages ..

Good reasons that were mentionned were the use of scripting languages that update extremely frequently, but certainly not for compiled code, compiling code on a production machine also is a big nono.

There also was a consensus that you DO NOT PUT CONFIGURATION inside a package. You can put in default templates, but you don't put in config files that should change frequently .. There's plenty of configuration mgmt systems out there do that kind of stuff for you.

The naysayers claimed that packaging brings way to much overhead ... and others claim it takes to much time... however I feel it
should just be a 1 time effort that brings devs and ops closer to eachother and from there on it should automated
New versions of software don't mean that the packaging effort needs to be done again..

Another topic that gathered lots of questions was if you should be capable of installing multiple versions of the same package , lots of people mentionned they didn't like fiddling with symlinks however the best comment in that discussion was that there is already a system out there , the alternatives setup .. provide by most operating systems that allow you to do so in a pretty clean way. I must admit I should look into alternatives more in depth too ..

The ever recurring question is wether one should package war files ? Sure as you then can also use the dependency models a package mgmt system brings to deploy the dependent libraries.

However when people ship products, rather than a live service they seem to package everything , mainly because the code in the product isn't changing as quickly as a live website, or internally used application.

The biggest problem however is the frustration people have with GEM or CPAN packages .. they add yet another layer of management to a system, most lots of CPAN packages are already packaged.. but when it comes to GEM's disaster strikes. There's a lot of work left for distributions to integrate GEM and CPAN style packages.

Oct 30 2010

Puppet broke my Xen

Actually it didn't , but now I got your attention.
We just adopted the use of adding headers to all of our files that are managed by puppet so people will know not to touch it

  1. file {
  2. "/etc/xen/scripts/network-custom-vlan-bridges":
  3. owner => "root",
  4. group => "root",
  5. mode => "0755",
  6. content => template(
  7. "headers/header-hash.erb',
  8. "xen/co-mmx-network-custom-vlan-bridges.erb");
  9. }

All worked nice however upon bootstrapping our Xen host the bridges stopped working .. running the network-custom-vlan-bridges script manually solved everything and created the appropriate bridges. But at boottime it didn't..

I added some debug info to the script and figured it never got executed at boot time.

Turns out that when I removed the headers Xen actually does configure the bridges at boot time, Xen probably checks for a shebang at the beginning of the file.

Putting the header at the end of the file therefore solved the problem. ,

Oct 18 2010

Le Tablet nouveau est arrivee

So I bought myselve a new gadget, a tablet. I wanted a couple of things, first of all I love the mythdroid app as a remote control for my MythTV, but as it runs on my phone and kids don't have a phone it was pretty much a blocking issue when I wasn't at home.
The second thing I wanted was a device for the kids to play small games on ... and I also want to use it for the kids to watch some movies while we travel. On top of that it would be handy if I could use it to surf the web from my couch while not having to open up my laptop.

I was looking into buying an Achos 10.1 which was due to be released earlier this month but I was fed up with waiting so I went googling for an alternative , and I found one .. it's an Apad, or an e-pad .. I still don't know .. the box says epad
ebay listed it as a 10.2" Android 2.1 Epad Apad 1GHZ Tablet PC UMPC Netbook It's not an iPad, .. it's chinese and it costs 1/3 of an iPad and it runs Android. Yes that's right .. I had it delivered from the UK within 2 working days for just about 200 Euro including shipping.
Ordered on thursday afternoon .. on my desk before 10AM on monday.

Opening the box was a bit scary .. it had a weird e logo on the side wich some people recognised as a kind of browser logo that I`m unfamiliar with and the acommpanying manual was only mentioning an platform I don't want to use , however booting up the device reassured me .. there was a nice penguin on the bootup screen and seconds later an android logo appeared.

The Good:

The device is really easy to work with , kids can use it .. (that was the goal wasn't it ? ) It has a USB slot where you can plug in external storage
and it has a SD slot for similar use .. it came with a 512Mb SD card which I replaced with an 8Gb one . It has an ethernet connection an extention cable with a real RJ45 connection . Lots of apps are available from it's market

The Bad:

It's not your default Google Market, the device has no access to the Google App Market but uses SlideMarket, not all apps are availble for download that way, however nothing blocks you from downloading .apk files and installing them on the device. For now I just swapped the SD card from my phone to get all the apps I wanted in a quick way but I should actually test plugging in my Android Phone using the USB and install the applications from the backup as the phone does have access to to the Google Market (Update: this actually works)

Not all apps are using the full screen estate, they've been written with 3-4 inch phone screens in mind and not with a 10" tablet in mind. I've heard the same rants about using iPhone apps on the iPad. The fontsize of the device is configurable but not all text adapts to the new font size and it also looks like the wifi chipset isn't the best around.. I often have to reconnect to my wifi

The Ugly:

Battery life is really not good enough .. it should last 3-4 hours but it didn't even last 2 hours when I first used it .. however I was busy installing new apps and testing lots of stuff so in

I haven't figured out how to configure gmail, gtail and other google services yet I should probably debug what's going on one day to see if it's actually a connectivity issue or if big G just blocks access from the device.

Would I consider it a 1 on 1 replacement for an iPad ? Probably not ... it's not as stylish as the fruit device but looking at the features I wanted compared to the price I paid for it , it's the perfect gadget ...

If I want to work I`ll open my laptop, when travelling I`ll be using my EEE , but to play with the kids and lookup stuff from the couch while watching TV it's going to be a 10" tablet.

Oct 02 2010

Busy weeks coming up ..

The next 2 months promise to be the more busier of the year for me .

On october 11th I`ll be giving a presentation ab out Linux and High Availability at the KAHO Sint Lieven in Gent

Just 2 days later I`ll be leaving to Hamburg for the next European version of DevopsDays 2010.

Between Devopsdays Hamburg and Leaving for Malaga I`ll visit CloudCamp Ghent om October 20th.

I'll be in Malaga for the Software Libre Open Source World Conference which will take place on 27 and 28 october

The first weekend of November I`ll be at T-Dose , where I`ll give 2 presentations on Devops.

As I`m part of the program comittee of this years NLUUG Najaars conference on Security , I`ll be spending my official Belgian holliday "working" at a conference in the Netherlands.

And to finish off I`ll be talking Devops again at Devoxx 2010 together with Patrick Debois

Don't hesitate to say hi when you bump in to me :)

Sep 01 2010

Pidgin and OAUth

So earlier today the nice folks over at twitter figured it was a good time to change all the authentication to oauth ... they might have announced it all over the place .. but it never catched my attention

The onlything that did catch my attention was that after not having ued pidgin for about 2 weeks I didn't have access to twitter anymore.

I`m using the purple-microblog plugin and the default version of that plugin in Fedora 12 wasn't really up2date. The plugin supports OAuth as of 3.0 which was released ages ago.

The version in fedora-updates-testing however was already recent enough ..

So enabling that repo and running
yum  update  purple-microblog
quickly solved my proble .. till I disabled twitter in my pidgin again as there was way to much talk about some weird fruit ...

Aug 04 2010

Mollom and Views

You might have noticed that this blog stopped accepting comments about a month ago.. well. stopped accepting is a big word.. I was still accepting comments, only they were never submitted to the database and after entering a comment to my blog people ended up on a white page.

So upon returning from holliday I set out to debug the issue together with one of our Inuits Drupal geeks and quickly ran into the following error.

  1. PHP Fatal error: Call to a member function has_more_records() on a non-object in /somepath/modules/views/plugins/views_plugin_display.inc on line 1992, referer: http://www.krisbuytaert.be/blog/comment/reply/1014

So apparently my veasion of views 6.x-3.0-alpha3 didn't really like to play with Mollom,
I downgraded views again to 6.x-2.11 and Mollom started showing its Captcha's etc again .

So apart from wondering how I ended up installing that alpha3 version (I`m sure Drush didn't do that), all is back to normal. and you should be able to comment on this blog again

Jul 19 2010

yum install mariadb

I`m not the biggest fan of openSUSE but this weeks post by Colin Charles makes me happy ..

openSUSE users can now do a mariadb install from their default repositories.

With all the fuzz about Snoracle and MySQL's future last year to me it became clear that we would end up having different MySQL based distributions, probably with different names, and that it would be up to the Linux distributions to provide the users with what they preferred, working with those Linux distributions
therefore would be very important for the MySQL distributions.

Sadly my Fedora box doesn't allow me to do a yum install mariadb yet ... but I`m sure that's only a matter of time ..

Jun 21 2010

A parallel universe

What happens when you mention Open Office and Firewall in once sentence, in public ?

People start actually building it (French Article)

Then add to that list that there's also people out there that think that running MySQL over NFS is providing them High Availability, or that using DNS Round Robin will provide them a scalable setup,

So yes .. apparently there is indeed a parallel universe out there.

And no .. I don't want to see Webmin in any Appliance .. that is a joke..., or rather a rant ..