Virtkick Docs

Documentation and information to Virtkick your business

How to Change to a Stock Kernel in CentOS 7

One of the requirements for running Virtkick on your hypervisor is a stock CentOS 7 kernel (el7.x86_64). If you use an OVH dedicated server, their custom kernel is acceptable too (xxxx-grs-ipv6-64). This article will discuss how this can be accomplished on your hypervisor.

1. Check if you have the right kernel

First run uname -r to verify whether you're running a correct version of kernel or not. If the output ends with el7.x86_64 or xxxx-grs-ipv6-64, you're good - Virtkick fully supports your kernel.

1. Download the new kernel

You can do this simply by running the following command:

yum install kernel

2. Verify the kernel exists

Next, make sure the kernel is now in the /boot directory. For example, you should see something similar to this:

-rwxr-xr-x  1 root root 5.0M Feb 16 12:13 vmlinuz-3.10.0-327.10.1.el7.x86_64
-rw-------  1 root root  11M Feb 17 21:10 initramfs-3.10.0-327.10.1.el7.x86_64.img

Your output will have more than this, but the important part is verifying you have a vmlinuz-* and initramfs-* matching the kernel version you downloaded. If you have those files you can proceed on to the next step.

3. Update Grub

For the purposes of this article we will be modifying a grub2 configuration.

Your grub configuration is likely located in /boot/grub2 from there find grub.cfg. Open it with your favorite text editor and look for the boot entry you are currently using. This will look something like the output below:

menuentry 'Centos 7' {
  . . .
  linux /boot/vmlinuz-foo root=/dev/sda1 . . .
  initrd /boot/initramfs-foo.img

You will need to edit the lines shown above. The linux parameter may have additional options following root=, don't worry if you have more.

Edit the linux line to point to /boot/vmlinuz-*, replace the -* with the file you found in step two. Do the same for initrd, be sure to include the .img extension at the end.

4. Reboot and verify

After your grub.cfg is updated you can reboot your server. Once the server is running again you can execute uname -r to verify the running kernel is the version you expect. The output should end with el7.x86_64 or xxxx-grs-ipv6-64.

5. Connect your Hypervisor

You are now all set to connect your hypervisor to your Virtkick panel! Have any trouble? Let us know - we are happy to help.

Back to the list ยป

Joe Pettit
Developer @ Virtkick
comments powered by Disqus