Showing posts from September, 2016

Issues to display SNMP information

This is a typical error on snmpwalk at the beginning of the display information:

snmpwalk -v1 -c public system
Expected "::=" (RFC5644): At line 493 in /usr/share/mibs/iana/IANA-IPPM-METRICS-REGISTRY-MIB
Expected "{" (EOF): At line 651 in /usr/share/mibs/iana/IANA-IPPM-METRICS-REGISTRY-MIB
Bad object identifier: At line 651 in /usr/share/mibs/iana/IANA-IPPM-METRICS-REGISTRY-MIB
Bad parse of OBJECT-IDENTITY: At line 651 in /usr/share/mibs/iana/IANA-IPPM-METRICS-REGISTRY-MIB
Bad operator (INTEGER): At line 73 in /usr/share/mibs/ietf/SNMPv2-PDU
Unlinked OID in IPATM-IPMC-MIB: marsMIB ::= { mib-2 57 }
Undefined identifier: mib-2 near line 18 of /usr/share/mibs/ietf/IPATM-IPMC-MIB

Open /etc/snmp/snmp.conf and it should be as follows:

mibs :
mibs +SNMPv2-MIB

But, if you run ...

snmptranslate -m all -Tz -On | sed -e 's/"//g' > /tmp/oids.txt

... to create your oids.txt, you still see the same error.
To fix them, you can edit the file /usr/share/mibs/iana/IAN…

Grafana's save/remove button does not appear on version 2.6

I'm using grafana 2.6 (from repositories), but I can't save or delete any dashboard. I try with chrome and firefox from linux but none work properly.

To fix it, you need to install the last version (3.1.1)
If you remove and purge grafana maybe you will get this error:

sudo apt-get purge grafana
Purging configuration files for grafana (2.6.0+dfsg-1) ...
dpkg: warning: while removing grafana, directory '/var/log/grafana' not empty so not removed
dpkg: warning: while removing grafana, directory '/var/lib/grafana' not empty so not removed

To fix it, just remove them:

sudo rm /var/log/grafana
sudo rm /var/lib/grafana

Now, proceed to install the last version:

sudo dpkg -i grafana_3.1.1-1470047149_amd64.deb
(Reading database ... 416705 files and directories currently installed.)
Preparing to unpack grafana_3.1.1-1470047149_amd64.deb ...
Unpacking grafana (3.1.1-1470047149) ...
dpkg: error processi…

Ping plugin for Telegraf to ping multiple ips and export it to InfluxDB

First, proceed to generate your telegraf configuration file with ping plugin enabled:

telegraf -sample-config -input-filter ping -output-filter influxdb > telegraf_ping.conf

If you want to do the classic ping with 1 sec interval, edit the following options:

  interval = "1s"
  flush_interval = "1s"

  urls = ["",""]  #Add your ips list
  count = 1
  ping_interval = 1.0
  timeout = 0.0

Now, to run it, execute:

telegraf -config telegraf_ping.conf

Meanwhile, you can show it on Grafana:

Enjoy it!

How to add CPU load value to your InfluxDB with bash scripting

First, we going to create a database with an example value, like this example:

Now, with a bash script we going to write to our database the first value from /proc/loadavg, every 5s:

while true; do curl -i -XPOST 'http://localhost:8086/write?db=stat' --data-binary "cpu,host=SERVER001 value=`cat /proc/loadavg | awk '{print $1}'`"; sleep 5;done

Plot a sine function with Python + InfluxDB + Grafana

I found an updated code for InfluxDB v0.10.0 and I fork the proyect. The code is here:

Just create a test database in InfluxDB and run

How to configure SNMP in mininet

First, you need to install snmp on your system:

sudo apt-get install snmp snmpd

Now, procced to configure snmp with the respective information about your machine:

sudo mv /etc/snmp/snmpd.conf  /etc/snmp/
sudo vim /etc/snmp/snmpd.conf
#Add these lines
#Change public by your SecretPassword if you like
rocommunity  public
syslocation  "Somewhere"

Now, edit the snmp daemon to listen all interfaces:

sudo vim /etc/default/snmpd
Change from:
# snmpd options (use syslog, close stdin/out/err).
SNMPDOPTS='-Lsd -Lf /dev/null -u snmp -I -smux -p /var/run/'

# snmpd options (use syslog, close stdin/out/err).
#SNMPDOPTS='-Lsd -Lf /dev/null -u snmp -I -smux -p /var/run/'
SNMPDOPTS='-Lsd -Lf /dev/null -u snmp -I -smux -p /var/run/ -c /etc/snmp/snmpd.conf'

Now, restart the daemon with:

 /etc/init.d/snmpd restart

To check it's all ok, run this follow command:

snmpwalk -v1 -c pub…

TERM environment variable not set on Python

To avoid this warning when you try clear your console through os.system('clear') on linux, you must configure TERM variable on your environment with "xterm-color" value.
In Pycharm, you can add it on File/Settings.../Build, Execution, Deployment/ Console/Python Console

Enjoy it!

How to execute Python scripts in Android

First, you need to install QPython in your Android.
To access to your Android console, you can use SSHDroid (remote access) or Terminal Emulator (local access).

Python for Android depends from a lot bash scripts. You need use all of them to run it.
Now, you need add to your PATH (configurable in init.environ.rc), python executable.
Other option is create symbolic links of your apps to /system/bin, as follow:

mount -o rw,remount /system
cd /system/bin
ln -s /data/data/org.qpython.qpy/files/bin/ 
ln -s /data/data/org.qpython.qpy/files/bin/python-android5
ln -s /data/data/org.qpython.qpy/files/bin/
ln -s /data/data/org.qpython.qpy/files/bin/ python

Now you can run python on your console :)
To execute a python script without calls to python, you must write on the first line of your script this line:


To execute the script, give it execution permission throught the console:

chmod +x $

you can run the script throught your console as follo…

How to enable Sphinx documentation in Pycharm

Sphinx is a tool that makes it easy to create documentation. It was originally created for the new Python documentation, and enables to create it on html, LaTeX or linkcheck.
See this blog for more information about Shpinx

First, you need install Shpinx it on your system:

pip install Sphinx

Now, you need configurate the project folder from Pycharm on Tools/Sphinx Quickstart

You should get this error:

ReStructuredText Error 
No sdk specified

To solve it, use the same solution that in this previous post

Now, you can compile your code to generate a html or a LaTeX file. Go to your project folder on your terminal and write:

#if you want html
make html
#if you want LaTeX
make latex

If you want generate this from Pycharm, you need create an external tool.
Go to File/Settings.../Tools/External Tools/ and add the following configuration:

Go to Tools/External Tools/Generate HTML and you will see the following output:

Your html file will be in build/html folder, inside your project.
Examples of s…

external link opened a blank tab in chrome

This is a common problem, when you try login to your facebook account throught an external application, like Spotify Web Player for Linux
As you know, create a password to use spotify stand alone (withut your facebook account) that they give you it's almost impossible.
When you click to login with your facebook account, if you use chrome, it will open an empty new tab an it's impossible login in to your account.
To fix it, just follow this command:

rm $HOME/.local/share/applications/google-chrome.desktop

Enjoy it!

Error: Cannot start process, the working directory does not exist

I got this error on Pycharm Python Console. It's an error running console.

To solve it, just remove .idea folder in your project and re run Pycharm.
Enjoy it!

How to write a file code template in Pycharm

To add utf-8 compatibility in all your scripts, one solution is enable a template that add this compatibility and other information as copyright, your name, etc.
File and code templates are written in the Velocity Template Language (VTL). So you may include variables as ${YEAR}, ${USER}, etc.
To add code to your scritps go to File/Settings.../Editor/File and Code Templates
Select Python Script and add the following lines:

#!/usr/bin/env python2
# -*- coding: utf-8 -*-
# Copyright (C) ${YEAR} ${USER}

Now, if you create a new Python file, it will generate with this header code by default.
If you want more VTL variables please go here
Enjoy it!

How to configure Pycharm with github

If you configured a previous project with your github account and now you try to work on it with Pycharm, yu will see this message when you'll start this IDE:

Unregistered VCS root detected
The directory ... is under Git, but is not registered in the Settings.
Add root  Configure  Ignore

Press Add root to add your folder to the git project configured on it.

Go to the Version Control tab and start to add files to it with Add to VCS (or press Ctrl + Alt + A on the file) on the ChangeList catalogued as Unversioned Files.

When you are done, click on Commit Changes

Now, write your Commit Message and push the Commit button and choose Commit and Push

Write your github user and password and you are done.

Enjoy it!

Interactive RYU controller with Postman

A good way to communicate with your RYU controller is through Postman.
You can find a lot of frequently curl requests on OF-DPA Ryu Rest, and you can import them to Postman.

You can download them from (you need a previous registration) or download from this link

Now, import them from Postman

And now, enjoy it!

You can use this video as tutorial

Synchronize your project with github

To synchronize your project (folder) with git hub, first check connectivity with them. Create an ssh key with your github mail (the mail that you use to login) and copy it in your github account. Later check the connection. Follow these commands:

apt-get install openssh-server
ssh-keygen -t rsa -C ""
cd ~/.ssh/
#Copy this key to your github config
#Now, check connectivity to github
ssh -vT

Now, create a new project on github page. To upload the content to github, follow these steps:

git branch --set-upstream master origin/master
git config --global "$USER"
git config --global "$MAIL"
git init
#Now, add all files in your folder
git add *
git commit -m "$MESSAGE"
git status
git remote add origin$USER/$PROJECT_NAME
git push origin master

A common error is the following:

! [rejected]        master -> master (fetch first)
error: failed to push some refs

Enable Python interactive console in PyCharm

Python has an interactive console that enable to explore your code after executing the script or the   command.
If you run your code without interactive option you will see this message:

Process finished with exit code 0

To activate it, go to Run/Edit Configurations ... remove all configurations (to the right of plus green icon) and write -i on interpreter options from Defaults/Python.

Also, you can enable Show command line afterwards checkbox, but your script may crash with this  following error, when try to read a string from the keyboard.

Exception in thread ServerThread (most likely raised during interpreter shutdown):

Process finished with exit code 1

Enjoy it!

Cannot find required executable controller

This is a typical problem when you try to run mininet topologies created with

Cannot find required executable controller.
Please make sure that it is installed and available in your $PATH:

Many blogs said that the solution is rename ovs-controller to controller

sudo ln /usr/bin/ovs-controller /usr/bin/controller

, but ovs-controller does not exist anymore. This is, because ovs-controller has been renamed test-controller.

To solve it, you need to create a symbolic link to ovs-testcontroller that is called controller.
Install openvswitch-testcontroller if you don't have it.

sudo apt-get install openvswitch-testcontroller
sudo ln /usr/bin/ovs-testcontroller /usr/bin/controller

Install PyCharm Community Edition 2016.2.3 on Ubuntu with IPython/Jupyter Notebook compatibility

PyCharm is another IDE for Python (in my last post I see how to install Spyder)
It has the advantage that you have multiples modes of view.  My favourite is the presentation Mode, perfect when you have a presentation and you need magnify the fonts and you need to show a on-demand code execution.
Also, you can install jupyter to run ipython notebook inside the IDE.  To install PyCharm follow these commands:
wget tar xvf pycharm-community-2016.2.3.tar.gz cd pycharm-community-2016.2.3/bin ./

Now, to install ipython and jupyter, follow these commands:
sudo apt-get install ipython-notebook sudo pip install jupyter
Run PyCharm and now create a new project. Now, create a new Jupyter Notebook with an ".ipynb" extension (IPYthon NoteBook):

In the first cell puts: %matplotlib inline This sentence enable to display figures on the same interface.  To exeute push SHIFT+Enter or click on play icon. Now enter th…

How to install Spyder 3.0 developer version

Spyder is a Scientific PYthon Development EnviRonment (IDE).
To install it from github you need following these commands:

git clone
cd spyder
python install

Failed to import qtpy.
Please check Spyder istallation requirements:
qtpy 1.1.0+ and either
PyQt5 5.2+ or
PyQt4 4.6+

If you get this error, you must install dependencies:

sudo apt-get install python-pip
pip install --upgrade pip
sudo pip install qtpy qtawesome pickleshare pep8 qtconsole nbconvert

Now, if you like a icon on your desktop to run Spyder just with one click, you need create spyder.desktop file on your Desktop with these lines:

[Desktop Entry]
Comment="Start Spyder"

Remember change ${SPYDER_FOLDER} with the PATH where you downloaded Spyder

Enjoy it!

Intel AES New Instructions (AESNI) libraries for C on Ubuntu

First, you need to check if your CPU is compatible with hardware accelerated Intel technology for cipher/decrypt with AES.

Next, we need to download the Intel AESNI library and compile it:

cd Intel_AESNI_Sample_Library_v1.2

Maybe, you will get the following errror:

collect2: error: ld returned 1 exit status
Got error on link

If you get it, please install yasm sudo apt-get install yasm
Now, compile it again: ./      ~/Downloads/Intel_AESNI_Sample_Library_v1.2/aes_example ~/Downloads/Intel_AESNI_Sample_Library_v1.2/aes_example ~/Downloads/Intel_AESNI_Sample_Library_v1.2/intel_aes_lib ~/Downloads/Intel_AESNI_Sample_Library_v1.2/intel_aes_lib do iaesx64.s do do_rdtsc.s ~/Downloads/Intel_AESNI_Sample_Library_v1.2/intel_aes_lib ~/Downloads/Intel_AESNI_Sample_Library_v1.2/aes_example mkdir: cannot create directory ‘bin’: File exists src…

UUID of the medium does not match the value stored in the media registry

If you try to load a VM to VBox and it name previously exists in the records with a different UUID, you will get this error.
In VBox you will see a message that said your hard disk is inaccessible.
To fix it, you need replace the new UUID in the configuration (.vbox file) of your VM.
Copy from ~/.config/VirtualBox/VirtualBox.xml the respective UUID from your virtual disk (see MachineEntry uuid). After, replace the UUID in your .vbox configuration file inside your VM folder.
Enjoy it!

Increment your VM storage size in VBox

The reason of this tutorial is because I was playing with a Virtual Machine and I overfill the hardisk space.
To resize the storage, first you need de-attach the hardisk from your VM and close VBOX.
Later, you need convert your .vmdk to a .vdi file with the following command:

vboxmanage clonehd ./machine.vmdk clone.vdi --format vdi 

VBoxManage: error: Cannot register the hard disk 'machine.vmdk' {4e55fd9e-f496-4cbf-9610-ad2f8c6b8634} because a hard disk 'machine.vmdk' with UUID {4e55fd9e-f496-4cbf-9610-ad2f8c6b8634} already exists
VBoxManage: error: Details: code NS_ERROR_INVALID_ARG (0x80070057), component VirtualBoxWrap, interface IVirtualBox, callee nsISupports
VBoxManage: error: Context: "OpenMedium(Bstr(pszFilenameOrUuid).raw(), enmDevType, enmAccessMode, fForceNewUuidOnOpen, pMedium.asOutParam())" at line 178 of file VBoxManageDisk.cpp

If you get this error, you must change the UUID from your VM with the following command:

vboxmanage internalcommands sethduu…

Could not get the storage format of the medium .iso (VERR_NOT_SUPPORTED).

This is a typical problem in VBox when you try to load a corrupted iso file.

Check if your iso has the same original iso hash with the following commad:
md5sum file.iso
In my case, I could check the hash in gparted download section, and effectively was different.

Topology Generator for ns3 on Ubuntu 16.04

While I find a solution to execute different BRITE configuration files or how to export ns2 topologies to ns3, I found this application compatible with ns-3.25 (since last week available).
To try it, follow these commands:

git clone
cd Topology_Generator 

You can generate a C++ or a Python code and export your topology as XML code. Also, you can create applications, like ping, UDP Echo or TCP Transfer.

I tested and it works! Enjoy it!

Creating topologies with BRITE to NS (Network Simulator)

BRITE (Boston University Representative Internet Topology Generator) is a tool to create topologies using Barabasi Albert or Waxman model. You can export the topologies to different formats like BRITE, Otter, SSF, JSim and NS.

You can use the configuration files available on BRITE repositorie for nsnam, but are only a few of them.

You can run the different configurations modifing the confFile variable inside the file or with the following command:

./waf --run 'brite-generic-example --confFile=src/brite/examples/conf_files/TD_ASBarabasi_RTWaxman.conf'

If you try other configuration file you will get this following error:

Program received signal SIGSEGV, Segmentation fault.
0x0000000000410faf in ns3::PeekPointer<ns3::Node> (p=...) at ./ns3/ptr.h:564
564  return p.m_ptr;

(gdb) where
#0  0x0000000000410faf in ns3::PeekPointer<ns3::Node> (p=...) at ./ns3/ptr.h:564
#1  0x00000000004105e4 in ns3::Ptr<ns3::Node>::Ptr (this=0x7fffffffcfa0, o=...) at ./ns3/ptr.h:739
#2  …

How to install MarketPlace Client on Eclipse CDT

If you download the Eclipse CDT version from the eclipse webpage, this version doesn't come with marketplace client by default. Eclipse CDT uses eclipse 3.8 (Indigo version).
To install it, you need to do the following steps:

Go to Help->Install New Software...
Point to Eclipse Indigo Site, If not available add the site "Indigo -"
Work with the above site
Look at "General Purpose Tools"->Marketplace Client

After install it, restart Eclipse and you could find Marketplace in Help->Eclipse Marketplace...

Now, you can install each plugin through marketplace. Enjoy it!

Resource name without extension to use as variable in external tools on Eclipse

In my last post about how to configure ns3 on Eclipse I gave the file name through a string prompt variable ("${string_prompt}"). This method is bored, for this reason I searched, how to give the file name without the extension automatically.
StartExplorer is a plugin for Eclipse and in their web, they mentioned the following:

In addition, StartExplorer itself offers a few variables of its own.

${resource_name_without_extension}: File name or directory name of the resource, without path and without extension (that is, resource, without trailing dot)

Also, the plugin Pathtool is another plugin with several variables.

I installed them using the MarketPlace client (see how to install marketplace on Eclipse CDT), but the variable that I want didn't appear in the variable list.

To automate the execution of my simulations, I created a bash script that calls waf (called wafEclipse) and parse the file name to remove the extension .cc
This is the wafEclipse code: