Is your problem on hand: CentOS 7 VM fails to boot after yum update? Find out how our Support Engineers tackle this problem.

Recently, one of our customers’ observed that their virtual machine fails to boot after yum update even with OnApp. Fortunately, our Support Team helped them out immediately. Let’s take a look at how they resolved the issue.

What to do if CentOS 7 VM fails to boot after yum update

Before we start, let’s take a look at what the log says once your VM fails to boot after running the “yum update”.

Fatal: VM was not running 1 minute after being started

The environment can be any VM installed or upgraded to CentOS 7.

In case, this is the scenario on hand, continue reading to find out what our Support Engineers recommend.

The first step is to look for a missing line for the default kernel in /boot/grub/grub.conf. The initial entry will look the same as the older entry, the missing line will be something like initrd.

/boot/initramfs-<kernel release>.img

For instance, here are a few lines from /etc/grub.conf:

title CentOS Linux (3.10.0-229.1.2.el7.x86_64) 7 (Core)
        root (hd0,0)
        kernel /boot/vmlinuz-3.10.0-229.1.2.el7.x86_64 root=/dev/xvda1 console=tty0 ro vconsole.keymap=us vconsole.font=latarcyrheb-sun16 LANG=en_US.UTF-8
        initrd /boot/initramfs-3.10.0-229.1.2.el7.x86_64.img

Well, the easiest way to fix this is to go to recovery mode. Then mount the failed virtual machine disk. After that, edit the file via vi or any other text editor.

We would also like to point out that CentOS 7 template comes with a custom kernel from OnApp. It has missing features that enable the VNC console to function smoothly. Unfortunately, the default updated kernel installed along with the yum update need not work with the VNC console. It will most probably leave the console blank/black.

[Looking for assistance? Give Bobcares a try.]

Conclusion

At the end of the day, we learned how to resolve the issues when CentOS 7 VM fails to boot after yum update from the experts at Bobcares.