Thursday, November 14, 2013

Enable access from other hosts to a MySQL server

Recently I deployed a MySQL server. But there was a problem that I could not access the data base from a application which was hosted in another server. The reason for this is by default MySQL server does not accepts requests from other hosts except the localhost.
To solve this problem we have to do two tasks.


  • Create a user which has permissions to read and write to a database from a different host
GRANT ALL PRIVILEGES
ON database.*
TO ‘user’@'yourremotehost'
IDENTIFIED BY 'newpassword';

As an exmaple following query enables root user to access all the databases from any host.

GRANT ALL PRIVILEGES ON *.* TO 'root'@'%' IDENTIFIED BY 'password';

  • Bind the ip adress
To do this you have to edit the MySQL configuration file. In Ubuntu this is /etc/mysql/my.cnf
There you can find an entry like
bind-address = 127.0.0.1 

If you want to enable access from all the host just remove it. If you want to limit the hosts you can add entries like
bind-address = your ip

After doing that you have to restart the MySQL server. In Ubuntu you can do that like below.
sudo /etc/init.d/mysql restart


Saturday, November 2, 2013

Install Oracle Java Development Kit on Ubuntu

Installing Java SDK is very straight forward in Windows. Download Java installer double click it and follow the steps. But installing Java in Ubuntu is not easy like that. In Ubuntu we can easily install Open JDK by providing following command. 

sudo apt-get install openjdk-6-jdk

 But this installs Open JDK not Oracle JDK. This is not a problem for entry level Java developers. But if you work in a production environment you cannot use Open JDK since most products use Oracle Java. Until recently the method I followed to install Oracle Java was downloading the tar.gz file form Oracle site and install it using the terminal. But this is very time consuming and there are lot of configurations has to be followed. But here is a very easy way to install the latest Oracle JDK in you machine without not needing to do any additional configurations. Just issue following three commands in the terminal to install Oracle JDK in your Ubuntu machine.


sudo add-apt-repository ppa:webupd8team/java
sudo apt-get update 
sudo apt-get install oracle-java7-installer