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Wednesday, February 27, 2013

What is Openflow

The OpenFlow standard is no longer anything new but rather a new low level protocol that network vendors are implementing in upcoming hardware. For these who would like to find out more about how it works and what it does the 'Origins and Evolution of OpenFlow/SDN - Martin Casado' video will give you a quick introduction. Below I put as well some of my notes I found interesting.

What is Openflow
  • Openflow is an interface to the switch.
  • It relays on the existing hardware you have; the hardware will still perform the same. functions it was originally designed for but we are going to have better manageability interface.
  • It allows us to decouple data plane from control plane.
  • It allows to create a more agile network environment in comparison to conventional network architectures.
Why we need Openflow

We have been taught that network is reliable, robust and can easily handle any type of changes. But in reality the bigger the network the more static it becomes. It is harder and harder to implement any changes. And to get it done it may requires a lot of careful planing and detailed implementation steps. As an example for a single change you may need to:
  • Reconfigure switches and change security parameters.
  • Adjust VLAN id.
  • Reconfigure your (global) routing policies.
  • change ACL on FW.
Often because of the operational complexities your network have to be simplified and follow certain constrain how the whole topology can look like. When it comes to changes we can never exclude the human error factor as well of course.

What problem does Openflow and SDN try to solve
  • Unified and vendor independent API to mange data plan in network hardware.
  • Provide API to manage state on the network device.
  • Provide a pragmatic way how to manage all of the datapath state in the network.
  • Decouple the software control distribution model from network hardware and topology.
  • Logically centralize control plane in the loosely coupled heterogeneous environments.
  • What openflow and sdn does it allows you to decouple the distribution model of your control logic from the physical topology.
What are the values and benefits of Openflow and SDN
  • Allow development of new network models and new types of function and services.
  • Innovate in the network as well network infrastructure areas.
  • Horizontal integrity.
  • The decoupling of the control and data layers will help to evolve them independently and lead to creation of better products.
  • With SDN you can do new things that are not possible within standard network - for example complete network tearing down and provisioning on demand
  • SDN is the way how you can manage the complexity within your distributed network
  • Allow to innovate on faster speed in networking

Does Rackspace use SDN to build its network in data centers

Rackspace have lunched a while ago cloud network product that provide the networking services as well as is the network infrastructure building block for the Openstack based cloud images. It can be pictured in this simple way like below.

But what vendor does Rackspace use to build its SDN based cloud network?

The cloud network at Rack is based on Nicira NVP product line. More info how we use and what it allows us to achieve can be found in the 'Nicira: Creating Virtual Networks in Cloud Data Centers' video.

Tuesday, February 26, 2013

Google uses OpenFlow and SDN in its data centers

I tried to describe what SDN is for network industry and how it works in this series of articles Today I've found a nice video 'OpenFlow @ Google - Urs Hoelzle, Google' that confirms that Google network uses Openflow and is build in a SDN like way. Take your time and happy watching.

How to build a data center

Working for a global hosting company can be a big fun and challenge every day. There is always something happening and changes are constant. But majority of us visit a data center only rarely or only at the beginning I believe. For these who would like to know a little more and understand why it may take a while to build a row in data center and fill it full with servers and network gear take a look at these example movies below. It is a good fun to watch ;).

Sunday, February 24, 2013

Openstack bugs

When working with upstream version of Openstack it helps to know what is happening in the source repository and especially what bugs are getting hot or popular. Below are couple of links for the Openstack project that help to stay on top with code code changes and bugs.

Where can I find all new and old bugs for Openstack

Even though the source code is maintained on the bugs are tracked on

How to search through all open bugs

Navigate to and use the search feature.

How to subscribe to all new bugs in every Openstack project

If you wish to be notified about every bug that is opened for any of the Openstack project you have to:
Is it possible to get a notification when a new bug is open for 'nova' project

Yes, you can receive email for every new bug that somebody opens. To subscribe to a bug mail list please:

Friday, February 22, 2013

My GNU gpg recipes

My public GNU gpg key

A link to the always up to date public key can be found here:  -> EF9C6A5F .

Version: GnuPG v1.4.11 (GNU/Linux)


To export a key
$ gpg --armor --output --export EF9C6A5F 
$ gpg --armor --output rado.pri.key --export-secret-keys EF9C6A5F 

To import a pub/priv key
$ gpg --allow-secret-key-import --import rado.pri.key 
$ gpg --import

To list keys
$ gpg --list-keys
gpg: checking the trustdb
gpg: no ultimately trusted keys found

$ gpg --list-keys
pub   2048R/EF9C6A5F 2013-02-22 [expires: 2017-02-21]
uid                  Radoslaw Tomaszewski 
sub   2048R/366D1276 2013-02-22

$ gpg --list-secret-keys
sec   2048R/EF9C6A5F 2013-02-22 [expires: 2017-02-21]
uid                  Radoslaw Tomaszewski 
ssb   2048R/366D1276 2013-02-22

To encrypt a message with my public key
$ gpg --armor -r EF9C6A5F -e file.txt

To decrypt a message with private key
$ gpg -d file.txt.asc

Upload your key to Launchpad
$ gpg --send-keys --keyserver EF9C6A5F
gpg: sending key EF9C6A5F to hkp server
rado@laptop:~/$ gpg --fingerprint EF9C6A5F 
pub   2048R/EF9C6A5F 2013-02-22 [expires: 2017-02-21]
      Key fingerprint = 978C 670D F864 8723 C2D2  C9F0 F8D0 6506 EF9C 6A5F
uid                  Radoslaw Tomaszewski 
sub   2048R/366D1276 2013-02-22


Sunday, February 17, 2013

Role of cloud computing in the ITIL

The longer you work in IT and see how companies evolve the more you realize that technology alone is not enough to be a successful on the market. At certain point in a company's live there is going to be a need to create or start establishing sound internal process to support the business if you want to continue to grow.

As cloud enable rapid  development and expansion the moment can come more sooner than later. But when it comes what are you gong to do? Maybe we could take a look at ITIL and see if this is an applicable framework and a solution for us. In the video from MicroNugget  'MicroNugget: Cloud Computing's Role in ITIL 2011' we can find an interesting introduction and references to further material on ITIL and cloud together.

Wednesday, February 13, 2013

Top membership on OpenStack mailing lists

Users' affiliations

The Openstack mailing lists are open. Everyone can subscribe. The top list of users' affiliations was created base on the frequency and a number of subscribed users [1]:
  1. RackSpace
  2. HP 
  3. Dell          
  4. Mirantis
  5. Cisco
  6. IBM
  7. EMC
  8. SUSE
  9. Nebula
  10. Canonical
  11. VMWare
  12. Red Hat
  13. Dreamhost
Mailing list

There are number of OpenStack Mailing Lists you can subscript to. Across all of them there are about 7000 individual members [1]. There are about 65 messages per day[2]. On average every months seems to generate more and more posts about the Openstack technology.

How to searching the archive

The lists archive can be found below together with a nice Google trick how to search.
  1. General list:
  2. Dev list:
  3. Operator list:
As an example for the general list you can search for interesting posts there using this Google trick: 



Sunday, February 10, 2013

My git recipes

  1. To download the repository to your local host
  2. $ git clone

    Or you can upload a public SSH key to your github account as described here and then clone using SSH method.

    $ git clone

  3. To commit and upload the source back to repository
  4. $ cd #repo#
    $ git add
    $ git commit -m 'init'
    $ git push origin master

  5. To update your local repository with the master
  6. $ cd #repo#
    $ git pull
    $ git pull origin master

  7. List config settings
  8. $ cd #repo#
    $ git config -l 

  9. Rename a file
  10. $ cd #repo#
    $ git mv README
    $ git commit -m "renamed"
    $ git push origin master

How to automatically adjust mouse wheel scrolling in windows

My old mouse got broken and and I've bought a new mouse to replace it. The hardware works fine the only problem is that every time when I restart my windows its get a random value of the "Roll the wheel one notch to scroll" value. You can imagine that when the values have 30 a single wheel notch scrolls 30 lines of text in my browser what makes it very annoying.


How to change the value of "Roll the wheel one notch to scroll" on windows start to lower value.

Analisis and solution description

We are going to use autoit tools[1] that provide automation features for Windows and allow us to modify the registry after system boot. This is the parameter that controls mouse wheel[2]:
HKEY_CURRENT_USER\Control Panel\Desktop\WheelScrollLines

A script that sets the registry variable to a new value can be found here:

To run it from command line please execute this command and check on Control Panel if the right value has changed:
"C:\Program Files (x86)\AutoIt3\AutoIt3.exe" wheel-scroling.au3

The last thing is to create a *.bat script and add it to logon/startup list to be run after user login[3]:
  • Run the gpedit.msc 
  • Navigate to the User Configuration > Windows Settings > Scripts(Log on/Log off) option.
  • Add your *.bat script

Friday, February 8, 2013

How to create startup usb disk to flash BIOS

I needed upgrade my BIOS. When looking into it I've been surprised how long did it took me to find the right tool and to how many issues i run when trying and testing it. Hopefully this post will help others to get it quicker.


How to create a bootable usb pendrive that can be used to flush Bios

Solution 1 (tested)

This solution is based on: HP Flash Utility - HP USB Disk Storage Format Tool.

To create a USB that can be used to boot a system into old DOS system please follow these steps:
  • Download the HP Flash Utility and Windows 98 MS-DOS System Files 
  • Extract and run the hpflash1 installer
  • Extract the contents of "win98boot" to a location readily accessible 
  • If you want to use the graphical interface HPUSBFW.EXE make sure you modify your PATH so you can run HPUSBF.EXE from cmd. 
  • Regardless is you are going to use the command line or the graphical interface make sure you run it 'As Administrator'
  • For the graphical installer under Format Options tick the "Create a DOS startup disk" option. Click the "..." button near the empty text box to browse to the location of where you extracted the Windows 98 MS-DOS System Files Verification.
One finished the USB will have these files in only:
J:\> DIR /A
  Directory of J:\

05/11/1998  07:01 PM           222,390 IO.SYS
05/11/1998  07:01 PM                 0 MSDOS.SYS
05/11/1998  07:01 PM            93,880 COMMAND.COM
               3 File(s)        316,270 bytes
Solution 2 (found later and not tested)

Download the Unetbootin utility ( and install FreeDOS onto USB drive.

Bios upgrade

Once the USB has been created you need to copy there all BIOS.ROM files you need. Finally restart the system and let it boot from USB. Once you get access to the DOS command prompt you need to follow you BIOS upgrade instruction.

My USB drive before reboot had these following files:
J:\> DIR /A
  Directory of J:\

05/11/1998  07:01 PM           222,390 IO.SYS
05/11/1998  07:01 PM                 0 MSDOS.SYS
05/11/1998  07:01 PM            93,880 COMMAND.COM
11/01/2012  05:38 PM                39 flash.bat
11/01/2012  05:16 PM         4,194,304 8225v303.ROM
12/13/2010  04:55 PM           153,824 AFUDOS.Exe
  1. USB
  3. Alternative solution
  5. Others

Saturday, February 2, 2013

How many instances can you run under the AWS Free Tier usage

The free usage tier on Amazon is a nice and convenient way for a quick check how AWS cloud works. But if you overuse it at the end of the months are will have to pay the bill that they sent you.

For example in the free tier [1] you have:

750 hours of EC2 running Linux/Unix Micro instance usage

That practically means you can have a one single tiny instance for a month for free. But every next will add to your monthly bill. That means that if you leave two instances to run over a month will have a similar bill to pay.

Expand All Services | Collapse All ServicesPrinter Friendly Version
$17.71AWS Service Charges
Amazon Elastic Compute Cloud 
Download Usage Report »
US East (Northern Virginia) Region
Amazon EC2 running Linux/UNIX
$0.00 per Micro Instance (t1.micro) instance-hour (or partial hour) under monthly free tier750 Hrs0.00
$0.020 per Micro Instance (t1.micro) instance-hour (or partial hour)738 Hrs14.76
Amazon EC2 EBS
$0.00 per GB-month of provisioned storage under monthly free tier16.000 GB-Mo0.00
$0.00 per 1 million I/O requests under monthly free tier240,182 IOs0.00
Amazon CloudWatch
$0.00 per metric-month - first 10 metrics7.000 Metrics0.00
AWS Data Transfer (excluding Amazon CloudFront)$0.00
 VAT to be collected$2.95
 GST to be collected$0.00
 US Tax to be collected$0.00