Unable to set password error while Mysql Data Migration - mysql

Question

I am trying to migrate mysql databases from one server to another. I am following these steps for the migration (270GB of data including databases and users in datadir):
sudo service mysql stop
sudo apt-get purge mysql-server-5.5 mysql-common
sudo rm -rf /var/lib/mysql
sudo rm -rf /etc/mysql
sudo ln -s <path to datadir>/mysql /var/lib/mysql
sudo apt-get clean
sudo apt-get purge mysql*
sudo apt-get update
sudo apt-get install -f
sudo apt-get install mysql-server-5.5
This asks for root password, which I try to set accordingly. However, I am getting the following response:
Configuring mysql-server-5.5
Unable to set password for the MySQL "root" user
An error occurred while setting the password for the MySQL administrative
user. This may have happened because the account already has a password, or
because of a communication problem with the MySQL server.
You should check the account's password after the package installation.
Please read the /usr/share/doc/mysql-server-5.5/README.Debian file for more
information.
Note that I followed the same steps on another ubuntu server (dev) based on the same AMI and was successful in doing the setup. The only variable between the two is data.
I cannot afford much downtime, and therefore using rsync for data replication.
I know that both the ubuntu and mysql versions are old, but this migration is necessary and has strict deadlines.

Answer 1

The solution here was pretty simple.
Rebooting the ubuntu server after following the steps to purge mysql* worked for me. Steps:
sudo service mysql stop
sudo apt-get purge mysql-server-5.5 mysql-common
sudo rm -rf /var/lib/mysql
sudo rm -rf /etc/mysql
sudo ln -s <path to datadir>/mysql /var/lib/mysql
sudo apt-get clean
sudo apt-get purge mysql*
Reboot the ubuntu machine.
Then:
sudo apt-get update
sudo apt-get install -f
sudo apt-get install mysql-server-5.5