How to upgrade Plesk 10 to Plesk 11 in CentOs 6

Before starting upgrade process please check Plesk 11 system requirement and make sure you have complete backup of your websites and databases. Also, make dump of your plesk database before starting upgrade process. It will require to restore in case something went wrong. Also, please note that most of the time upgrade process fails because of EPEL repository. To complete upgrade process without any error disables the EPEL repository by doing:

cd /etc/yum.repos.d
mv epel.repo epel.repo_back
mv epel-testing.repo epel-testing.repo.back 

Once you are done with the above steps, start the upgrade process using the following steps:

Log in the server and Download the auto installer using the following command:

For CentOs x64:
Wget http://download1.parallels.com/Plesk/PP11/11.0/CentOS6/parallels_installer_v3.12.0_build120601.16_os_CentOS_6_x86_64

For CentOs x86:
Wget http://download1.parallels.com/Plesk/PP11/11.0/CentOS6/parallels_installer_v3.12.0_build120601.16_os_CentOS_6_i386 

Once you download auto installer, start the upgrade process using the cmd or GUI mode:

Upgrade using Plesk 10 GUI

Login in your plesk panel using https://domainname:8443 or https://serveripaddress:8443

Once you are in your panel goto Server Management > Tools & Settings > Panel > Update and Upgrades > Install or Upgrade Product to start the upgrade process.

To upgrade the plesk panel via SSH

Run the following command from shell as super user(root):

/opt/psa/admin/bin/autoinstaller
or
/usr/local/psa/admin/bin/autoinstaller 

After upgrading process of Plesk is complete, please check Plesk upgrade/update history and the installed version, do the following in SSH to check the same:

mysql -uadmin -p`cat /etc/psa/.psa.shadow`;
use psa
select * from upgrade_history;

If all goes well and you dont see any errors on the screen plesk is upgraded successfully. login in you plesk and enjoy.