OVH Servers affected by known Citrix bug CTX127395

Posted abril 9th, 2012 in Blog, Virtualization by Alfredo

If you have some XenServer 5.6 host that randomly (and suddenly) becomes completely unresponsive with no apparent reason, then it might be affected by an odd bug that has been documented by Citrix.

Is my server affected?

Potentially, any server based on the Nehalem (Xeon 75xx, 55xx, 35xx, 34xx) and Westmere (Xeon 56xx, 36xx) architectures can be affected.

How to know if my XenServer 5.6 is affected?

  1. Open a console to your XenServer host (SSH client, the console tab in XenCenter, or the local console).
  2. Make sure that your server is running on any of the affected architectures. To find out, run:
  3. If it is,  with administrative privileges run:

If the value of total C-States is bigger than 2, then this server is affected by the bug and if necessary, they must be disabled from the BIOS.

How to fix?
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WebDevelopment using vagrant

Posted marzo 21st, 2012 in Blog, Web Development by Gastón Acosta Ramas

if you’re working on various web projects, and some of them are based in different technologies, and/or using different frameworks, it’s difficult to have one development environment, and keep it tidy, clean and working.

In my case, i’ve some projects under NginX others under Apache2, others in different architectures, and i’ve to test some projects in different SO.

well, here i’ll show you how i used vagrant as a solution for this problem.

vagrant uses VirtualBox headless to provide you, an easy to use/handle VM.

 

  1. download vagrant from here.
  2. add your boxes (base vms.) by default you can download ubuntu base box, but here, you have a list of Vagrant boxes you can add.
  3. usefull commands you should know.

in my case i have /home/gargrag/projects/, and inside one folder per project with a vagrant box .

editing Vagrantfile you could  forward ports to your phisical vm, add shared folders and setup many other things like chef provisioning.

for example you can forward 3306 to 3306, 80 to 8080 and whatever you need.

 

happy develop!.

How to install Scrapy on debian using virtualenv

Posted febrero 15th, 2012 in Blog, Data and Metrics by admin

Scrapy allthough it’s in python is the best swiss army knife tool arround for scraping, forget about nokogiri :) or nasty perl regexp crawlers.. scrapy is serious bussines.

In this guide i will show you how to setup python virtualenvs and install the last version of scrapy into one. If you are not really familiar with virtualenvs i suggest you read http://pypi.python.org/pypi/virtualenv.

Before starting you need to install

Once all packages are installed, lets setup our first virtualenv

Now lets install scrapy from the nightly build version (if you want to install a stable version, just checkout a branch instead)

If you follow every steps and the all mighty gods of linux grant you their grace, hopefully everything should work and you can test it by just running:

Some helpfull links you may find cool:
* http://www.stereoplex.com/blog/understanding-imports-and-pythonpath | Everything you should know about python paths
* http://doc.scrapy.org/en/0.12/topics/architecture.html | Scrapy architecture overview