Matt Woodward's posterous

Matt Woodward's posterous

Matthew Woodward  //  * CFML, Grails, and Java Developer
* Principal IT Specialist, US Senate
* Open BlueDragon Steering Committee Member
* All-Around Geek

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CentOS

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Nov 8 / 9:34pm

Setting the Initial Root Password for MySQL on CentOS

by Matthew Woodward

I was setting up a new CentOS server tonight and installed MySQL via yum. If you're familiar with installing MySQL via apt-get on Debian-based systems, you'll know that during the install it prompts you to set the MySQL root password. Not so on CentOS.

When I've installed MySQL on CentOS in the past, I could have sworn the default root password was blank, and that right after the installation is complete you set it like so:

mysqladmin -u root password NEW_PASSWORD

Either my memory is foggy, or something's changed with how this is done. No matter what I tried I kept getting "access denied" messages from MySQL and of course since I never set a root password, I have no idea what it wants from me.

Luckily there's a solution, at least one that worked for me, though I still feel like I may be missing something so although this worked, I'm happy to be told there's a simpler way.

First, make sure no MySQL processes are running:

killall -9 mysqld

Next, start MySQL in safe mode and have it skip grant tables:

/usr/bin/mysqld_safe --skip-grant-tables &

This will let you get in as root without a password. After the process starts, log in and use the mysql database:

mysql -u root mysql

Next, set the root user password:

update user set password=PASSWORD('new_password') where user='root';

It should say 2 or 3 rows affected. Finally, flush the privileges:

flush privileges;

Quit MySQL, and then you'll want to kill the process you started with mysqld_safe and start the regular MySQL process. You can either bring the process you started earlier by typing 'fg', hitting enter, and then hitting ctrl-C to kill it, or you can do a ps -wef | grep mysqld to find the process ID and kill it as per usual.

Finally, restart MySQL and test your new root password:

/etc/init.d/mysqld start

mysql -u root -p

When it prompts you for the password, enter the password you set earlier and you should be logged in successfully.

Note this process also works if you've forgotten the MySQL root password.

Hope that save someone else a bit of time, and as I said earlier, I'll be very happy if someone has a better explanation of why I wasn't able to log in without a password on a fresh MySQL install on CentOS.

Filed under  //  CentOS   Linux   MySQL   Red Hat  
 
Feb 21 / 7:21am

Changing the Host Name on CentOS

by Matthew Woodward
I'm working on a project that is leveraging a third-party Java library to handle payment processing. This library is a for-pay product and the license is tied to the machine name, so the original license was being used on a local development box but now that we want to move things to the production server, the license wouldn't be valid since the production server's host name isn't the same as the local development box.

Apparently the company who sells the payment processing library can update the license file, but it seemed even easier to simply change the host name of the production server to match what the license is expecting. This way we can move the payment processing functionality to a different machine as needed without having to wait for a new license key to be issued.

The production server in this case is CentOS, so to change the host name you simply update /etc/sysconfig/network with the new host name and reboot.

This is slightly different from Ubuntu, which stores the host name in /etc/hostname. On Ubuntu you can also use the hostname command to change the hostname temporarily, but it will revert back to the value in /etc/hostname when you reboot.

Filed under  //  CentOS   Linux   Ubuntu