How do I convert my Linode CentOS server to CloudLinux?

Issue

How to correctly configure your Linode to run CloudLinux on it.

Environment

• CloudLinux OS 6(h)/7(h)/8
• cPanel/Plesk/DirectAdmin/No panel

Solution

This guide gives you an idea of how to correctly configure your Linode to run CloudLinux on it.

1. Make sure that you have successfully converted from CentOS to CloudLinux following the steps in this documentation.
   If you are installing CloudLInux 8, please make sure you’ve read this thread.
   
   After the conversion, you will probably get this warning at the end of cldeploy process.
   "Please edit configuration of your Linode and select "GRUB" in Boot Settings - Kernel"
   So, this is what we going to do next.
   
   
2. Make sure that grub of the appropriate version is installed:
   - CloudLinux 6: grub legacy is used
   

   [root@li629-209 ~]# rpm -qa|grep grub 
   grubby-7.0.15-7.el6.x86_64
   grub-0.97-99.el6.x86_64 

   - CloudLinux 7: grub2 is used

   [root@li629-209 ~]# rpm -qa|grep grub2
   grub2-tools-2.02-0.81.el7.cloudlinux.x86_64
   grub2-2.02-0.81.el7.cloudlinux.x86_64
   grub2-common-2.02-0.81.el7.cloudlinux.noarch
   grub2-tools-extra-2.02-0.81.el7.cloudlinux.x86_64
   grub2-pc-modules-2.02-0.81.el7.cloudlinux.noarch
   grub2-tools-minimal-2.02-0.81.el7.cloudlinux.x86_64
   grub2-pc-2.02-0.81.el7.cloudlinux.x86_64

   - CloudLinux 8: look for grub2-pc package

   [root@li629-209 ~]# rpm -qa|grep ^grub
   grub2-pc-modules-2.02-78.el8_1.1.noarch
   grub2-tools-extra-2.02-78.el8_1.1.x86_64
   grub2-common-2.02-78.el8_1.1.noarch
   grub2-pc-2.02-78.el8_1.1.x86_64
   grub2-tools-minimal-2.02-78.el8_1.1.x86_64
   grub2-tools-2.02-78.el8_1.1.x86_64
   grubby-8.40-37.el8.x86_64

3. Check that grub configuration is present:
   - CloudLinux 6: check /boot/grub/grub.conf and /boot/grub/menu.lst files.
   

   [root@li629-209 ~]# ll /boot/grub/menu.lst
   lrwxrwxrwx 1 root root 20 Jun 10 09:50 /boot/grub/menu.lst -> /boot/grub/grub.conf

   [root@li629-209 ~]# cat /boot/grub/grub.conf
   default=0
   timeout=5
   title CloudLinux Server (2.6.32-954.3.5.lve1.4.78.el6.x86_64)
   root (hd0)
   kernel /boot/vmlinuz-2.6.32-954.3.5.lve1.4.78.el6.x86_64 root=/dev/sda ro
   initrd /boot/initramfs-2.6.32-954.3.5.lve1.4.78.el6.x86_64.img

   - CloudLinux 7: check/boot/grub2/grub.cfg

   [root@li629-209 ~]# grep "/boot/vmlinuz" /boot/grub2/grub.cfg
    linux16 /boot/vmlinuz-3.10.0-962.3.2.lve1.5.36.el7.x86_64 root=/dev/sda ro console=ttyS0,19200n8 net.ifnames=0 crashkernel=auto rhgb LANG=en_US.UTF-8
    linux16 /boot/vmlinuz-0-rescue-db65f445ec2645d1b6edf88fda1bc8b4 root=/dev/sda ro console=ttyS0,19200n8 net.ifnames=0 crashkernel=auto rhgb LANG=en_US.UTF-8
    linux16 /boot/vmlinuz-3.10.0-1127.el7.x86_64 root=/dev/sda ro console=ttyS0,19200n8 net.ifnames=0 crashkernel=auto rhgb
    linux16 /boot/vmlinuz-0-rescue-9931d1dc0ce6417da266556c2dc336b1 root=/dev/sda ro console=ttyS0,19200n8 net.ifnames=0 crashkernel=auto rhgb

   - CloudLinux 8: check the directory # ls /boot/loader/entries/ . The filenames there consist of a machine ID stored in the /etc/machine-id file, and a kernel version.

   [root@li629-209 ~]# ll /boot/loader/entries/
   total 8
   -rw-r--r--. 1 root root 416 Jun 10 11:07 2f283665f5784f228b05f82e3bb2758e-0-rescue.conf
   -rw-r--r--. 1 root root 394 Jun 10 11:07 2f283665f5784f228b05f82e3bb2758e-4.18.0-147.8.1.el8.lve.x86_64.conf
   [root@li629-209 ~]# cat /etc/machine-id 
   2f283665f5784f228b05f82e3bb2758e

4. Go to Linode Dashboard of this VM -> Disks/Configs tab and edit your Configuration under Boot Settings -> Select a Kernel.
   - For CloudLinux 6: find Grub (Legacy) there and save the configuration.
   - For CloudLinux 7 and CloudLinux 8: find Grub 2 there and save the configuration.
   
   
5. Reboot the machine and check the kernel. It should have "lve" in its name.
   - CloudLinux 6:

   [root@li629-209 ~]# uname -r
   2.6.32-954.3.5.lve1.4.78.el6.x86_64

   - CloudLinux 7:

   [root@li629-209 ~]# uname -r
   3.10.0-962.3.2.lve1.5.36.el7.x86_64

   - CloudLinux 8:

   [root@li629-209 ~]# uname -r
   4.18.0-147.8.1.el8.lve.x86_64

Note!
This guide doesn't cover old Xen Linode setups. We have separate docs entry for these. 

It is also possible to run Hybrid CloudLinux kernels on your Linodes the same way. You can read more here.