[Virtual Switching] What are macvlan and macvtap?

I excerpt the content of the following URL about what macvlan and macvtap are for reference quickly.
https://www.netdev01.org/docs/netdev_tutorial_bridge_makita_150213.pdf

macvlan
VLAN using not 802.1Q tag but mac address
    • 4 types of mode
        • private
        • vepa
        • bridge
        • passthru
Using unicast filtering if supported, instead of promiscuous mode (except for passthru)
    • Unicast filtering allows

NIC to receive multiple mac addresses
    • Light weight bridge
    • No source learning
    • No STP
Only one uplink
Allow traffic between macvlans (via macvlan stack)


macvtap
with KVM has three mode
    Private
    vepa
    bridge
tap-like macvlan variant
    • packet reception
        -> file read
    • file write
        -> packet transmission



Further reading:
http://140.120.15.179/Presentation/20150203/
Virtual networking: TUN/TAP, MacVLAN, and MacVTap

[GitHub] How to rebase your branch from upstream branch?

If you fork a copy (branch) from a repository and you want to rebase your branch with this upstream repository, you can refer to the following URLs or directly see the content below.

https://help.github.com/articles/configuring-a-remote-for-a-fork/
https://help.github.com/articles/syncing-a-fork/

1. List the current configured remote repository for your fork.

   git remote -v
   # origin  https://github.com/YOUR_USERNAME/YOUR_FORK.git (fetch)
   # origin  https://github.com/YOUR_USERNAME/YOUR_FORK.git (push)
   

2. Specify a new remote upstream repository that will be synced with the fork.

   git remote add upstream https://github.com/ORIGINAL_OWNER/ORIGINAL_REPOSITORY.git
   

3. Verify the new upstream repository you've specified for your fork.

   git remote -v
   # origin    https://github.com/YOUR_USERNAME/YOUR_FORK.git (fetch)
   # origin    https://github.com/YOUR_USERNAME/YOUR_FORK.git (push)
   # upstream  https://github.com/ORIGINAL_OWNER/ORIGINAL_REPOSITORY.git (fetch)
   # upstream  https://github.com/ORIGINAL_OWNER/ORIGINAL_REPOSITORY.git (push)
   

1. Fetch the branches and their respective commits from the upstream repository. Commits tomaster will be stored in a local branch, upstream/master.

   git fetch upstream
   # remote: Counting objects: 75, done.
   # remote: Compressing objects: 100% (53/53), done.
   # remote: Total 62 (delta 27), reused 44 (delta 9)
   # Unpacking objects: 100% (62/62), done.
   # From https://github.com/ORIGINAL_OWNER/ORIGINAL_REPOSITORY
   #  * [new branch]      master     -> upstream/master
   

2. Check out your fork's local master branch.

   git checkout master
   # Switched to branch 'master'
   

3. Merge the changes from upstream/master into your local master branch. This brings your fork's master branch into sync with the upstream repository, without losing your local changes.

   git merge upstream/master
   # Updating a422352..5fdff0f
   # Fast-forward
   #  README                    |    9 -------
   #  README.md                 |    7 ++++++
   #  2 files changed, 7 insertions(+), 9 deletions(-)
   #  delete mode 100644 README
   #  create mode 100644 README.md
   

   If your local branch didn't have any unique commits, Git will instead perform a "fast-forward":

   git merge upstream/master
   # Updating 34e91da..16c56ad
   # Fast-forward
   #  README.md                 |    5 +++--
   #  1 file changed, 3 insertions(+), 2 deletions(-)

[Django] How to Find the Performance Bottlenecks in Your Django Views?

Do you want to find the performance bottlenecks in your Django Views? I recently found this article that introduces nice tools for us to check the performance issues in Django. How to do it? Please follow this URL:
http://djangotricks.blogspot.tw/2015/01/performance-bottlenecks-in-django-views.html

To setup line profiling, install line_profiler and django-devserver to you virtual environment:

(myproject_env)$ pip install line_profiler
(myproject_env)$ pip install django-devserver

Then make sure that you have the following settings in your settings.py or local_settings.py:

# settings.py
INSTALLED_APPS = (
    # ...
    'devserver',
)

MIDDLEWARE_CLASSES = (
    # ...
    'devserver.middleware.DevServerMiddleware',
)

DEVSERVER_MODULES = (
    'devserver.modules.sql.SQLRealTimeModule',
    'devserver.modules.sql.SQLSummaryModule',
    'devserver.modules.profile.ProfileSummaryModule',

    # Modules not enabled by default
    'devserver.modules.profile.LineProfilerModule',
)

DEVSERVER_AUTO_PROFILE = True  # profiles all views without the need of function decorator

I try these tools and get a bunch of analysis report from them, and I think they are useful and convenient. The following picture is one part of my result:

[Selenium] How to use xpath to define the locator in Selenium Library?

When I first time touch Selenium library in Robot Framework, the first question mark coming up in my mind is "How to use xpath to define the locator?"

 Here is an example. If I want to select the listbox that is near by my email td tag, and the HTML looks like the follows:

There could be several ways to do so. But, I like to use this way to achieve the action that I described below. "Select From List" is the standard keyword to do the action for selecting a list, but you have to give the locator. Based on my HTML code, the answer is this:

Another example, if I want to select the checkbox that is near by my email td tag, I can use the following way to do so:

Or, if I want to get some information in a table, what can I do for this?
OK, if I have the table's HTML code like this:

I can use "Get Table Cell" keyword with xpath //table[@class='your table's class name'] and the information in which row and column, then you can finish the task to get the data from the cell in the table. Here you go:


Reference:
http://stackoverflow.com/questions/247135/using-xpath-to-search-text-containing

[Python] How can I patch a Python decorator before it wraps a function?

As title, Python decorator could be a problem if you want to write some unit cases that test these functions which contains decorators because you cannot use Mock to patch your decorators. Why? Please refer to the following link to check out:

http://stackoverflow.com/questions/7667567/can-i-patch-a-python-decorator-before-it-wraps-a-function

Decorators are applied at function definition time. For most functions, this is when the module is loaded. (Functions that are defined in other functions have the decorator applied each time the enclosing function is called.)

So if you want to monkey-patch a decorator, what you need to do is:

1. Import the module that contains it
2. Define the mock decorator function
3. Set e.g. module.decorator = mymockdecorator
4. Import the module(s) that use the decorator, or use it in your own module

Let me give an exmple:

Here is a decorator function(user_passes_test) in the following file path

/usr/local/lib/python2.7/dist-packages/django/contrib/auth/decorators.py

If you have a function using this decorator and need to write the test case for it as follows:

@user_passes_test(filter_root,
                  login_url=settings.LOGIN_PAGE)
def my_dashboard_view(request):


Then, you can put your patch code in the beginning of the tests python file like this:


def mock_function(test_func, login_url=None, redirect_field_name=None):
    def wrapped_f(view_func):
        @wraps(view_func, assigned=available_attrs(view_func))
        def decorator_view(request, *args, **kwargs):
            return view_func(request, *args, **kwargs)
        return decorator_function
    return wrapped_f

from django.contrib.auth.decorators import user_passes_test
user_passes_test = mock_function


After doing so, the decorator:  user_passes_test() won't infect your test case any more~

[SSH] To examine the Linux PAM for login mechanism

Based on Linux PAM module, we can easily configure the related pam file and use the functionality that it provides. I just examine login authentication mechanism from PAM a little bit. The scenario is like this:
  I change the login authentication mechanism from key pair to password and to see what happens in /var/log/auth.log if I give the wrong password.

/etc/ssh/sshd_config

The value to change:

PubkeyAuthentication yes ==> no

PasswordAuthentication no ==> yes

$> service ssh restart

After restarting ssh daemon, I give the wrong password and then I can see the error message in the log file:

The following image is for reference if everything is correct.

[Make] Build the Linux Kernel

This document keeps my previous job that is to deal with re-building Linux Kernel for myself reference:

Modules存放位置:  /lib/modules/$(uname -r)/kernel/

核心檔案放置在:  /usr/src/kernels/`uname -r`/arch/x86/boot/bzImage

第一次進行編譯, 保持乾淨原始碼： make mrproper
其餘的時刻，你想要刪除前一次編譯過程的殘留資料: make clean

開始挑選核心功能： make XXconfig
make menuconfig

make help

[root@www linux-2.6.30.3]# make vmlinux  <==未經壓縮的核心
[root@www linux-2.6.30.3]# make modules  <==僅核心模組
[root@www linux-2.6.30.3]# make bzImage  <==經壓縮過的核心(預設)
[root@www linux-2.6.30.3]# make all      <==進行上述的三個動作


移動核心到 /boot 且保留舊核心檔案
[root@www ~]# cp /usr/src/kernels/linux-2.6.30.3/arch/x86/boot/bzImage \
> /boot/vmlinuz-2.6.30.3vbird  <==實際核心
[root@www ~]# cp /usr/src/kernels/linux-2.6.30.3/.config \
> /boot/config-2.6.30.3vbird   <==建議設定檔也複製備

建立相對應的 Initial Ram Disk (initrd)
mkinitrd -v /boot/initrd-2.6.30.3vbird.img  2.6.30.3vbird

編輯開機選單
vim /boot/grub/menu.lst

[Horizon] The summary of Horizon module

Basically Horizon is based on Django framework to be developed.

Install Horizon

To install the related packages for Horizon in Controller Node:

root@controller:~# apt-get -y install openstack-dashboard apache2 libapache2-mod-wsgi memcached python-memcache

Django setting 

Modify the file: /etc/openstack-dashboard/local_settings.py
Change the LOCATION's ip to controller's ip 

OPENSTACK_HOST = "controller"

# session ( default using memcached as session management )
CACHES = {
   'default': {
       'BACKEND': 'django.core.cache.backends.memcached.MemcachedCache',
       'LOCATION': '192.168.22.5:11211',
   }
}

# Time zone
TIME_ZONE = "Asia/Taipei"

Restart the service

Restart apache & memcached：

root@controller:~# service apache2 restart
root@controller:~# service memcached restart

Reference

The following list and items are the the related information when I study Horizon.



Openstack introduction:

http://www.slideshare.net/ya790026/openstack-34821569

Trace python code:

https://github.com/ya790206/call_seq

OpenStack APIs and WSGI

http://www.slideshare.net/lhrc_mikeyp/openstack-apis-and-wsgi?next_slideshow=1

SWGI

http://www.slideshare.net/mingli.yuan/a-brief-introduce-to-wsgi?next_slideshow=2

Pyreverse : UML Diagrams for Python (Logilab.org)