CentOS 7 does not start after kernel updates

The latest version of the CentOS 7 has a boot problem on our Xen platform. If you have a VPS with CentOS 7 and you run the kernel below (from 693):

3.10.0-693.xx

Or will update (through yum update) to this kernel, then the VPS will not boot due to this bug: https://bugs.centos.org/view.php?id=13763.

At the time of writing, September 2017, there is a workaround available that we describe below. If a fix is ​​available, we will apply this page.

Does this effect have on your VPS?

The following command shows which CentOS kernels are installed:

rpm -qa kernel

The output is as follows:

kernel-3.10.0-514.21.2.el7.x86_64
kernel-3.10.0-514.26.2.el7.x86_64
kernel-3.10.0-514.21.1.el7.x86_64
kernel-3.10.0-514.26.1.el7.x86_64
kernel-3.10.0-514.16.1.el7.x86_64

If you see a kernel with number 693 or higher in that list, it is already installed and you must complete the workaround by installing the patch. The work around can be find in the instructions below.

Prevent

If you have not updated yet, it is advisable to wait for updating until the bug is fixed and a new kernel is released. You can exclude kernel updates, so you can perform other updates except for the kernel. This can be achieved by updating the following file:

/etc/yum.conf

And make sure it containts the following line:

exclude=kernel kernel-devel kernel-PAE-*

If an exclude rule already exists, you must add "kernel *".

I rebooted and now the VPS is broken, help?

You can send us email support@sosys.net and we will help to reboot into your previous kernel. Or you can use the console mode to boot manually during grub window

The bug has been reported upstream: https://bugs.centos.org/view.php?id=13763#c30014

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