Evaggelos Balaskas - System Engineer

The sky above the port was the color of television, tuned to a dead channel

Blog
Posts
Wiki
About
Contact
rss.png twitter linkedin github gitlab profile for ebal on Stack Exchange

Restrict email addresses for sending emails »
  -  
« Packer by HashiCorp
May
23
2018
CentOS Bootstrap
Posted by ebal at 20:28:38 in blog, planet_ellak, planet_Sysadmin, planet_fsfe

CentOS 6

This way is been suggested for building a container image from your current centos system.

 

In my case, I need to remote upgrade a running centos6 system to a new clean centos7 on a test vps, without the need of opening the vnc console, attaching a new ISO etc etc.

I am rather lucky as I have a clean extra partition to this vps, so I will follow the below process to remote install a new clean CentOS 7 to this partition. Then add a new grub entry and boot into this partition.

 

Current OS

# cat /etc/redhat-release
CentOS release 6.9 (Final)

 

Format partition

format & mount the partition:

 mkfs.ext4 -L rootfs /dev/vda5
 mount /dev/vda5 /mnt/

 

InstallRoot

Type:

# yum -y groupinstall "Base" --releasever 7 --installroot /mnt/ --nogpgcheck

 

Test

test it, when finished:

mount --bind /dev/  /mnt/dev/
mount --bind /sys/  /mnt/sys/
mount --bind /proc/ /mnt/proc/

chroot /mnt/

bash-4.2#  cat /etc/redhat-release
CentOS Linux release 7.5.1804 (Core)

It works!

 

Root Password

inside chroot enviroment:

bash-4.2# passwd
Changing password for user root.
New password:
Retype new password:
passwd: all authentication tokens updated successfully.

bash-4.2# exit

 

Grub

adding the new grub entry for CentOS 7

title CentOS 7
        root (hd0,4)
        kernel /boot/vmlinuz-3.10.0-862.2.3.el7.x86_64 root=/dev/vda5 ro rhgb LANG=en_US.UTF-8
        initrd /boot/initramfs-3.10.0-862.2.3.el7.x86_64.img

by changing the default boot entry from 0 to 1 :

default=0

to

default=1

our system will boot into centos7 when reboot!

 

Restrict email addresses for sending emails »
  -  
« Packer by HashiCorp

Search

Admin area

  • Login

Categories

  • blog
  • wiki
  • pirsynd
  • midori
  • books
  • archlinux
  • movies
  • xfce
  • code
  • beer
  • planet_ellak
  • planet_Sysadmin
  • microblogging
  • UH572
  • KoboGlo
  • planet_fsfe

Archives

  • 2025
    • April
    • March
    • February
  • 2024
    • November
    • October
    • August
    • April
    • March
  • 2023
    • May
    • April
  • 2022
    • November
    • October
    • August
    • February
  • 2021
    • November
    • July
    • June
    • May
    • April
    • March
    • February
  • 2020
    • December
    • November
    • September
    • August
    • June
    • May
    • April
    • March
    • January
  • 2019
    • December
    • October
    • September
    • August
    • July
    • June
    • May
    • April
    • March
    • February
    • January
  • 2018
    • December
    • November
    • October
    • September
    • August
    • June
    • May
    • April
    • March
    • February
    • January
  • 2017
    • December
    • October
    • September
    • August
    • July
    • June
    • May
    • April
    • March
    • February
    • January
  • 2016
    • December
    • November
    • October
    • August
    • July
    • June
    • May
    • April
    • March
    • February
    • January
  • 2015
    • December
    • November
    • October
    • September
    • August
    • July
    • June
    • May
    • April
    • March
    • January
  • 2014
    • December
    • November
    • October
    • September
    • August
    • July
    • June
    • May
    • April
    • March
    • February
    • January
  • 2013
    • December
    • November
    • October
    • September
    • August
    • July
    • June
    • May
    • April
    • March
    • February
    • January
  • 2012
    • December
    • November
    • October
    • September
    • August
    • July
    • June
    • May
    • April
    • March
    • February
    • January
  • 2011
    • December
    • November
    • October
    • September
    • August
    • July
    • June
    • May
    • April
    • March
    • February
    • January
  • 2010
    • December
    • November
    • October
    • September
    • August
    • July
    • June
    • May
    • April
    • March
    • February
    • January
  • 2009
    • December
    • November
    • October
    • September
    • August
    • July
    • June
    • May
    • April
    • March
    • February
    • January
Ευάγγελος.Μπαλάσκας.gr

License GNU FDL 1.3 - CC BY-SA 3.0