Linux – Kernel update not being applied even after reboot

centoscentos7kernellinux

Here is my server details

cat /etc/*-release
CentOS Linux release 7.3.1611 (Core)
NAME="CentOS Linux"
VERSION="7 (Core)"
ID="centos"
ID_LIKE="rhel fedora"
VERSION_ID="7"
PRETTY_NAME="CentOS Linux 7 (Core)"
ANSI_COLOR="0;31"
CPE_NAME="cpe:/o:centos:centos:7"
HOME_URL="https://www.centos.org/"
BUG_REPORT_URL="https://bugs.centos.org/"

CENTOS_MANTISBT_PROJECT="CentOS-7"
CENTOS_MANTISBT_PROJECT_VERSION="7"
REDHAT_SUPPORT_PRODUCT="centos"
REDHAT_SUPPORT_PRODUCT_VERSION="7"

CentOS Linux release 7.3.1611 (Core)
CentOS Linux release 7.3.1611 (Core)

I wanted to update Kernel to latest version in order to run docker

I did update using yum update and showed me that its updating kernel to some 4.* version.

Then I did reboot

And then I saw 

[root@vps ~]# uname -r
2.6.32-042stab116.2

Its still running older version.

I tried solution from https://serverfault.com/a/623755/213444

But my server has no such files at those locations.

What is going wrong?

Best Answer

/Edit: Just read Thomas' comment about the kernel version 2.6.32-042stab116.2.

That's because your VPS provider is using Virtuozzo / OpenVZ containers. There are options to run docker in such environments:

https://openvz.org/Docker_inside_CT

However, sometimes customers are not able to request that the provider changes these settings. I also needed to move to a different, fully virtualized server in order to run docker.

Otherwise the following tipps could still be helpful for others:

Is /boot maybe located on another partition that was not mounted during kernel update? Or there was not enough space left on /boot and the install script bailed before successfully creating the initramfs and applying updates to the grub2.cfg.

Please check that /boot is mounted and both vmlinuz and initramfs for the new kernel are in place. Then manually invoke:

grub2-mkconfig -o /boot/grub2/grub.cfg

This updates the available boot stanzas in the grub2 config presented during system boot.

Another possibility:

In order to activate a new kernel, the system needs to be rebooted. If you used reboot -fmaybe the files were not correctly written to disk, yet.

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