Solution to Centos 7 default kernel updates, not supported on Xenserver VPS.
If you have installed Centos 7 on Xenserver VPS, and have tried upgrading Kernel on that vps, the vps may not come up again, post reboot.
The solution to this problem is, booting the Centos 7 back in one of the old kernels available. Once booted, install Elrepo kernel on Centos 7 vps using below procedure :
rpm -Uvh http://www.elrepo.org/elrepo-release-7.0-2.el7.elrepo.noarch.rpm
yum –enablerepo=elrepo-kernel install kernel-ml
grub2-mkconfig -o /boot/grub2/grub.cfg
This will install Elrepo kernel on your Centos 7 VPS on Xenserver, which is stable and good. You can then reboot your vps into new kernel.