Paul R. Ganci
2016-Oct-30 07:27 UTC
[CentOS] Cannot boot CentOS 7 VM after updating Host CentOS 7 Kernel
I have something very strange that occurred. After updating the kernel on my host CentOS 7 Dell 2950iii I have found that one of my CentOS 7 guest VMs will no longer boot... it just stops at the grub prompt (a second VM functions just fine). I have no idea why this problem occurred and have been unable to fix it. On google I have found several suggestions as to how to repair grub but so far none have worked. What I have found so far is this: grub> ls (hd0) (hd0,msdos2) (hd0,msdos1) grub> ls -l (hd0,1) (hd0,msdos2) (hd0,msdos1) Partition hd0,1: Filesystem type xfs, UUID 250008ab-9fde-4892-a8b7-a38882b1a1448 - Partition start at 1024KiB - Total size 512000Kib Partition hd0,msdos2: No known filesystem detected - Partition start at 513024KiB - Total size 12069888KiB Partition hd0,msdos1: Filesystem type xfs, UUID 250008ab-9fde-4892-a8b7-a38882b1a1448 - Partition start at 1024KiB - Total size 512000Kib So it appears that (hd0,1) and (hd0,msdos1) are the same partition containing the boot directory contents grub> set root=(hd0,1) grub> ls -l / DIR 20151002231139 grub/ DIR 20161013022100 grub2/ 10190975 20151219235512 initrd-plymouth.img 40655493 20150403032637 initramfs-0-rescue-6494b5d98adc4f66b0cf4c19a0f6ab66.img 4902656 20150403032703 vmlinuz0-rescue-6494b5d98adc4f66b0cf4c19a0f6ab66 252739 20161010232025 symvers-3.10.0-327.36.2.el7.x86_64.gz 29666884 20161013012551 initramfs-3.10.0-327.36.2.el7.x86_64.img 2965270 20161010231818 System.map-3.10.0-327.36.2.el7.x86_64 126431 20161010231818 config-3.10.0-327.36.2.el7.x86_64 5157936 20161010231819 vmlinuz-3.10.0-327.36.2.el7.x86_64 18119089 20161013022032 initramfs-3.10.0-327.36.2.el7.x86_64kdump.img Is that (hd0,msdos2) the root partition? If is, has it become corrupted somehow? Can I get this system to boot somehow so that I might fix the grub configuration? So far I have tried something along these lines with out success: grub> set root=(hd0,msdos2) grub> linux (hd0,1)/vmlinuz-3.10.0-327.36.2.el7.x86_64 root=(hd0,msdos2)/ grub> initrd initrd-plymouth.img grub> boot I just get this error: [ 2.128131] No filesystem could mount root, tried: [ 2.129038] Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(1,0) [ 2.130537] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.10.0-327.36.2.el7.x86_64 #1 [ 2.132017] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011 {remainder of stack dump} Does anyone have any ideas as to 1.) How to fix the problem? 2.) Why the problem occurred in the first place? 3.) How to go about debugging the problem? I would really like to know how this problem could have occurred on the 1 VM but the Host and 2nd Guest are just fine? Thanks for your help. -- Paul (ganci at nurdog.com) Cell: (303)257-5208
Steven Tardy
2016-Oct-30 12:57 UTC
[CentOS] Cannot boot CentOS 7 VM after updating Host CentOS 7 Kernel
> On Oct 30, 2016, at 3:27 AM, Paul R. Ganci <ganci at nurdog.com> wrote: > > grub> set root=(hd0,msdos2) > grub> linux (hd0,1)/vmlinuz-3.10.0-327.36.2.el7.x86_64 root=(hd0,msdos2)/ > grub> initrd initrd-plymouth.img > grub> bootTry the initrd matching the kernel?
FrancisM
2016-Oct-30 13:33 UTC
[CentOS] Cannot boot CentOS 7 VM after updating Host CentOS 7 Kernel
Any error in your host logs? On Sunday, 30 October 2016, Steven Tardy <sjt5atra at gmail.com> wrote:> > > On Oct 30, 2016, at 3:27 AM, Paul R. Ganci <ganci at nurdog.com > <javascript:;>> wrote: > > > > grub> set root=(hd0,msdos2) > > grub> linux (hd0,1)/vmlinuz-3.10.0-327.36.2.el7.x86_64 > root=(hd0,msdos2)/ > > grub> initrd initrd-plymouth.img > > grub> boot > > Try the initrd matching the kernel? > _______________________________________________ > CentOS mailing list > CentOS at centos.org <javascript:;> > https://lists.centos.org/mailman/listinfo/centos >
Paul R. Ganci
2016-Oct-30 17:58 UTC
[CentOS] Cannot boot CentOS 7 VM after updating Host CentOS 7 Kernel
On 10/30/2016 06:57 AM, Steven Tardy wrote:> On Oct 30, 2016, at 3:27 AM, Paul R. Ganci <ganci at nurdog.com> wrote: >> grub> set root=(hd0,msdos2) >> grub> linux (hd0,1)/vmlinuz-3.10.0-327.36.2.el7.x86_64 root=(hd0,msdos2)/ >> grub> initrd initrd-plymouth.img >> grub> boot > Try the initrd matching the kernelThat is what I thought was strange... there is no matching initrd. The only one there was the one I tried. I checked all the working systems both hosts and guests and they all just have a initrd-plymouth.img. -- Paul (ganci at nurdog.com) Cell: (303)257-5208
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