Docker : An Introduction to LXC

Docker is an open source project, which packages applications and their dependencies in a virtual container that can run on any Linux server. Docker has immense possibilities as it facilitates the running of several OS's on the same server.

Technology is changing faster than styles in than fashion world, and there are many new entrants specific to the open source, cloud, virtualisation, and DevOps technologies. Docker is one of them. The aim of this article is to give you a clear idea of Docker, its architecture and its functions, before getting started with it. 

Docker is a new open source tool based on Linux container technology(LXC), designed to change how you think about workload/application deployments. It helps you to easily create light-weight, self-sufficient, portable application containers that can be shared, modified and easily deployed to different infrastructure such as cloud/compute servers or bare metal servers. The Idea is to provide a comprehensive abstraction layer that allows developers to 'containerise' or 'package' any application  and have it run on any infrastructure.

Docker is based on container virtualisation and it is not new. There is no better tool than Docker to help manage kernel level technologies such as LXC, cgroups and a copy-on-write filesystems. It helps us manage the complicated kernel layer technologies through tools and APIs.

How to Increase PhpMyAdmin Session Timeout from 1440 seconds

phpMyAdmin is one of my favorite tools and I use it all the time. But man, the 24-minute session timeout is a huge problem . A short cookie lifetime is all well and good on your production server, but what about when you’re just testing new things  away on the computer in your test envirnment?
Did a little grepping and found that you can override this setting, even though it’s not documented anywhere but in the codes (so far as I can tell). To override it, just open up config.inc.php in the root phpMyAdmin directory and add this setting (anywhere, but  mostly at end of file):
phpmyadmin config file for ubuntu Server : /etc/phpmyadmin/config.inc.php

$cfg['LoginCookieValidity'] = <your_new_timeout>;

Where <your_new_timeout> is some number larger than 1800. Personally, I chose 28800, which is 8 hours.

Define how long a login cookie is valid. Please note that php configuration option session.gc_maxlifetime might limit session validity and if the session is lost, the login cookie is also invalidated. So it is a good idea to set session.gc_maxlifetime at least to the same value of $cfg['LoginCookieValidity'].
php.ini file for ubuntu Server : /etc/php5/apache2/php.ini

Disclaimer! It should go without saying that increasing the timeout is a (comparatively minor) security risk (but a risk nonetheless). Obviously, do not do this on your production server. And as always, proceed with caution.

Setting up a SVN Server on a EC2 Instance (Ubuntu 14.04 LTS)

Setting up an SVN server on my EC2 instance (on AWS), is a major problem whenever we connect svn using key-file(key.pem for AWS).
Here’s my situation:

• I have a micro EC2 instance hosted with Amazon.
• I used a non-standard port for ssh access
• I have a pem file provided by Amazon for access through ssh
• I run Ubuntu 14.04 Server on my EC2 instance
• On the client side, I’m running Ububtu 14.04 Desktop

With that out of the way, the first thing I had to do was insure svn was installed on my server and Desktop :

sudo apt-get install -y subversion

Then, on my EC2 instance, I want to create both the directory where I’ll store repositories, and the subsequently, create the repository itself. Permissions and ownership are of the utmost importance. This worked for me:

sudo mkdir -p /srv/svn/
sudo chown ubuntu:ubuntu /srv/svn/
svnadmin create /srv/svn/{repo_name}
Mind the {rep_name} placeholder above 

vim /svnrepos/conf/svnserve.conf

In that file add these three lines:

anon-access = none
auth-access = write
password-db = passwd

Create a password file:

vi /svnrepos/conf/passwd

In that file add a line for your user:

# add users in the format : user = password
tony = mypassword