Boot Ubuntu 16.04 in Console Mode.

Boot Ubuntu 16.04 in Console Mode/Text Mode 

Problem : Why I needed Ubuntu in console mode ?

While practicing HADOOP Installation in cluster mode , I was always ending up in creating a VM which is GUI enabled.

As already stated my laptop configuration is 4GB RAM constraint I was experiencing very slow system processing when 2 VMs were started at the same time as both were loading GUI interface of Ubuntu.

So thought came to my mind, for DATANODE there is no requirement of GUI so how can I disable it !!!

After reading about it I came to know changing GRUB settings this can be done .

So here is the procedure of doing the same.

very very imp: Take a backup of current grub file. sudo cp /etc/default/grub /etc/default/grub.orig

1) sudo vim /etc/default/grub

Make the following changes in grub file.

           1) Comment #GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

           2) GRUB_CMDLINE_LINUX="text"

           3)  Uncomment GRUB_TERMINAL=console

Changes looks like this

Save file .

2) Update GRUB to make changes to grub.cfg file 

Issue

update-grub

3) In Ubuntu version  16.04 issue this command so that change takes place for each user login

sudo systemctl set-default multi-user.target

4) Shutdown and start system . Ubuntu will be available in console mode.

Hope it helps !!

Unlocking root account Ubuntu 14.04 (Trusty) Ubuntu 16.04 (xenial)

Unlocking root account Ubuntu 14.04 (Trusty) Ubuntu 16.04 (xenial)

By default root account is locked on the system . 

Nobody directly logins to system as root but you can issue sudo to issue commands as root user .

For some applications it is required to have root account unlocked so that files can be saved in certain folders for eg in case of Ambari-server installation ssh public keys (id_rsa.pub) need to be stored as authorized_keys in .ssh directory of root account .

Here is the way to unlock root account .

1) Enable Password for rood user-id

sudo passwd root 

2) Unlock root account

sudo passwd -u root

To test :

Switch to root user  Issue

su - root

pwd   <<---present working director

Hope it helps !!!

Enjoy !!