Common Open Data Platforms
In the Open Data concept, certain organizational data are freely available for anyone to use and
republish as they wish, without any restrictions (copyrights, patents, etc.). This is similar to
concepts such as Open Source, Open Hardware, Open Government, and Open Knowledge. It became more
popular with the launch of Open Government Data (“Open Data”) initiatives adopted by
world super powers (USA – data.gov, UK – data.gov.uk, India – data.gov.in). Most of these Open Data
implementations were based on popular Open Data platforms/ frameworks already available in the
market.
Some such Open Data Platforms are Ckan [1], Dkan [2], Socrata [3] and Junar [4]. Out of these,
Ckan
and Dkan are known as Open Source Open Data Frameworks, which are extremely popular in the Open
Data
market. Both Ckan and Dkan follow the “All-in-One” (centralized) and federated data
management approaches, which were written in Python and Drupal/PHP languages respectively. Of these
frameworks, Ckan and Dkan are equally popular.
About Dkan
Dkan is a Drupal-based community-driven Open Source Open Data platform offering a full suite of
cataloging, publishing and visualization features. It allows organizations and individuals to have
ultimate freedom to publish and open data to the public.
Why this blog?
Having its roots in Drupal, the official Dkan installation guide basically follows Drush [5] as
the
base installation. Hence, due to the unavailability of the relevant literature related to cloud
deployment, having a complete and concise guide, in the form of this blog, would be beneficial to
many Dkan cloud developers, I hope.
In the next few sections, I will walk you through the steps relatto setting up Dkan without
downloading Drupal or its supporting modules.
Prerequisites
- Pre-configured EC2 Ubuntu Instance (18.04) – (t2.small
would suffice)
- Basic knowledge about Ubuntu terminal
Steps
SSH to your EC2 instance and update the instance.
After the update, install the following software to get it going.
01) Install Apache Server
- Run the following command to Install Apache server
- - sudo apt-get install apache2
- Verify the Apache server installation
- - sudo systemctl status apache2
- To stop, start and restart Apache server you can use
following commands.
- - sudo systemctl stop apache2
- - sudo systemctl start apache2
- - sudo systemctl restart apache2
02) Install Mysql Server
- Run the following command to install Mysql server
- - sudo service mysql stop
Once the installation is done, you can login to Mysql and create a database. To create a password
for Mysql, we need to reset the root password and set a new one for the “root” user.
- Let's start by stopping the running MySQL database:
- - sudo service mysql stop
- Next, create a /var/run/mysqld directory to be used by
MySQL process to store and access the socket file:
- - sudo mkdir -p /var/run/mysqld
- - sudo chown mysql:mysql /var/run/mysqld
- Once it is ready, manually start MySQL with the
following command and options:
- - sudo /usr/sbin/mysqld --skip-grant-tables --skip-networking &
- To confirm that the process is running as expected,
run the below command:
- - Jobs
- At this stage, it will allow us to access the MySQL
database without a password:
- - mysql -u root
- Now flush privileges:
- - FLUSH PRIVILEGES;
- Next, we will reset root password as ”dkanpassword”:
- - USE mysql;
- - UPDATE user SET authentication_string=PASSWORD("dkanpassword") WHERE User='root';
- - UPDATE user SET plugin="mysql_native_password" WHERE User='root';
- Quit MySQL session:
- - quit
- Then terminate the current mysqld process:
- - sudo pkill mysqld
- Finally, start the MYSQL database:
- - sudo service mysql start
- If all went well, you should now be able to login to
your MySQL database with the “root” password:
- - mysql -u root --password -p
- When it asks for the password provide it as
“dkanpassword” and you will be able to login successfully.
Then create a database with password. In this example I’m using “dkandb” as our database name.
- - create database dkandb;
- Then run the following command to verify that the
database was created successfully.
- - show databases;
03) PHP Installation with Required Modules
- We’ve planned to install the PHP 7.0 version since it is deemed the most suitable PHP version for the Dkan integration.
- - sudo apt install php7.0
- In Dkan, there are some functions like image streams which are directed to a browser. You will need to compile PHP with the GD library for this to work.
- - sudo apt install php7.0-gd
- The DOM extension allows you to operate on XML documents through the DOM API with PHP.
- - sudo apt-get install php7.0-dom
- Php-mysql provides the mysql module for php.
- - sudo apt-get install php7.0-mysql
- In Drupal, we need to have the unicode support with a php mbstring extension for it.
- - sudo apt-get install php7.0-mbstring
