SOLVED Service failures after upgrading system to CentOS version 7.6

avinash.pudota

Active Member
Jan 27, 2013
26
2
3
India
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Root Administrator
I think I found a solution. For me it works and I am now able to boot using my HDD kernel in CentOS 7.6
Working with the info from @greektranslator
Also looking in /var/log/grubby I found some info on missing uuid
So I figured I need to rebuild grub2. I did this before using this command :
Code:
grub2-mkconfig -o /boot/grub2/grub.cfg
But that didnt work for me
But I have the idea that since CentOS 7.6 some uefi things were added to grub2
So I found some info on rebuilding grub2 for uefi systems.
Code:
grub2-mkconfig -o /boot/efi/EFI/centos/grub.cfg
This seems to solve the issue for me . I did a reboot and now all is good. Will do some more testing and report if I occur any more problems.
Hi,
I have a similar problem, after 7.6 update server located at OVH wont boot, server was restarted using netboot.
I have disabled the selinux as recommended by cpanel support team and restarted with harddisk boot, but it still failed and i reverted back to netboot.

I have the below folders in /boot
efi
grub
grub2
and other files vmlinuz, initramfs, config....

in /boot/efi/EFI/centos folder i have only fonts folder, grubenv and grubx64.efi files, no grub.cfg file
in /boot/grub2 folder i have grub.cfg file


running grep vmlinuz /boot/grub2/grub.cfg returns below output
Code:
     linuxefi /vmlinuz-3.10.0-862.14.4.el7.x86_64 root=/dev/md3 ro crashkernel=auto rhgb quiet rd.md.uuid=dd1cafb8:967fe6e4:a4d2adc2:26fd5302 rd.md.uuid=a66932bf:6600cd22:a4d2adc2:26fd5302 rootdelay=10 rootdelay=10 LANG=en_US.UTF-8
        linuxefi /vmlinuz-3.10.0-862.11.6.el7.x86_64 root=/dev/md3 ro crashkernel=auto rhgb quiet rd.md.uuid=dd1cafb8:967fe6e4:a4d2adc2:26fd5302 rd.md.uuid=a66932bf:6600cd22:a4d2adc2:26fd5302 rootdelay=10 rootdelay=10 LANG=en_US.UTF-8
        linuxefi /vmlinuz-3.10.0-862.9.1.el7.x86_64 root=/dev/md3 ro crashkernel=auto rhgb quiet rd.md.uuid=dd1cafb8:967fe6e4:a4d2adc2:26fd5302 rd.md.uuid=a66932bf:6600cd22:a4d2adc2:26fd5302 rootdelay=10 rootdelay=10 LANG=en_US.UTF-8
        linuxefi /vmlinuz-3.10.0-862.3.2.el7.x86_64 root=/dev/md3 ro crashkernel=auto rhgb quiet rd.md.uuid=dd1cafb8:967fe6e4:a4d2adc2:26fd5302 rd.md.uuid=a66932bf:6600cd22:a4d2adc2:26fd5302 rootdelay=10 rootdelay=10 LANG=en_US.UTF-8
        linuxefi /vmlinuz-3.10.0-862.2.3.el7.x86_64 root=/dev/md3 ro crashkernel=auto rhgb quiet rd.md.uuid=dd1cafb8:967fe6e4:a4d2adc2:26fd5302 rd.md.uuid=a66932bf:6600cd22:a4d2adc2:26fd5302 rootdelay=10 rootdelay=10 LANG=en_US.UTF-8
        linuxefi /vmlinuz-0-rescue-485ccf091d93c1ef5d85bdf65ab397a6 root=/dev/md3 ro crashkernel=auto rhgb quiet rd.md.uuid=dd1cafb8:967fe6e4:a4d2adc2:26fd5302 rd.md.uuid=a66932bf:6600cd22:a4d2adc2:26fd5302 rootdelay=10 rootdelay=10
        linuxefi /vmlinuz-0-rescue-1e98a4cc1263468b9f9a12e365316b95 root=/dev/md3 ro crashkernel=auto rhgb quiet rd.md.uuid=dd1cafb8:967fe6e4:a4d2adc2:26fd5302 rd.md.uuid=a66932bf:6600cd22:a4d2adc2:26fd5302 rootdelay=10 rootdelay=10

running yum list 'grub2*' returns below output
Code:
Loaded plugins: fastestmirror, universal-hooks
Loading mirror speeds from cached hostfile
 * EA4: 85.13.201.2
 * cpanel-addons-production-feed: 85.13.201.2
 * base: centos.mirrors.ovh.net
 * extras: centos.mirrors.ovh.net
 * updates: centos.mirrors.ovh.net
Installed Packages
grub2.x86_64                                                               1:2.02-0.76.el7.centos                                              @base
grub2-common.noarch                                                        1:2.02-0.76.el7.centos                                              @base
grub2-efi-x64.x86_64                                                       1:2.02-0.76.el7.centos                                              @base
grub2-efi-x64-modules.noarch                                               1:2.02-0.76.el7.centos                                              @base
grub2-pc.x86_64                                                            1:2.02-0.76.el7.centos                                              @base
grub2-pc-modules.noarch                                                    1:2.02-0.76.el7.centos                                              @base
grub2-tools.x86_64                                                         1:2.02-0.76.el7.centos                                              @base
grub2-tools-extra.x86_64                                                   1:2.02-0.76.el7.centos                                              @base
grub2-tools-minimal.x86_64                                                 1:2.02-0.76.el7.centos                                              @base
Available Packages
grub2-efi-aa64-modules.noarch                                              1:2.02-0.76.el7.centos                                              base
grub2-efi-ia32.x86_64                                                      1:2.02-0.76.el7.centos                                              base
grub2-efi-ia32-cdboot.x86_64                                               1:2.02-0.76.el7.centos                                              base
grub2-efi-ia32-modules.noarch                                              1:2.02-0.76.el7.centos                                              base
grub2-efi-x64-cdboot.x86_64                                                1:2.02-0.76.el7.centos                                              base
grub2-ppc-modules.noarch                                                   1:2.02-0.76.el7.centos                                              base
grub2-ppc64-modules.noarch                                                 1:2.02-0.76.el7.centos                                              base
grub2-ppc64le-modules.noarch                                               1:2.02-0.76.el7.centos                                              base
 

avinash.pudota

Active Member
Jan 27, 2013
26
2
3
India
cPanel Access Level
Root Administrator
continued from above reply, sorry for posting early.

I am also getting this error in WHM -> Software Update page.
This error shows for about 1 second before the page loads but disappears after page loads, i have checked the source code of the page and it is available there, not sure if it is related to the issue, but i am getting this only after update.

This is the error
A warning occurred while processing this directive. (expanding this shows the below)
Code:
substr outside of string at /usr/local/cpanel/3rdparty/perl/526/lib64/perl5/cpanel_lib/x86_64-linux-64int/Template/VMethods.pm line 333.
at /usr/local/cpanel/3rdparty/perl/526/lib64/perl5/cpanel_lib/x86_64-linux-64int/Template/VMethods.pm line 333.
Template::VMethods::text_substr("", 1) called at /var/cpanel/template_compiles//usr/local/cpanel/whostmgr/docroot/templates/master_templates/_defheader.tmpl line 144
eval {...} called at /var/cpanel/template_compiles//usr/local/cpanel/whostmgr/docroot/templates/master_templates/_defheader.tmpl line 144
eval {...} called at /var/cpanel/template_compiles//usr/local/cpanel/whostmgr/docroot/templates/master_templates/_defheader.tmpl line 1
Template::Provider::__ANON__(Template::Context=HASH(0x269d0e0)) called at /usr/local/cpanel/3rdparty/perl/526/lib64/perl5/cpanel_lib/x86_64-linux-64int/Template/Document.pm line 162
eval {...} called at /usr/local/cpanel/3rdparty/perl/526/lib64/perl5/cpanel_lib/x86_64-linux-64int/Template/Document.pm line 160
Template::Document::process(Template::Document=HASH(0x2729210), Template::Context=HASH(0x269d0e0)) called at /usr/local/cpanel/3rdparty/perl/526/lib64/perl5/cpanel_lib/x86_64-linux-64int/Template/Context.pm line 357
eval {...} called at /usr/local/cpanel/3rdparty/perl/526/lib64/perl5/cpanel_lib/x86_64-linux-64int/Template/Context.pm line 327
Template::Context::process(Template::Context=HASH(0x269d0e0), "master_templates/_defheader.tmpl") called at /usr/local/cpanel/whostmgr/docroot/templates/master_templates/master.tmpl line 1
eval {...} called at /usr/local/cpanel/whostmgr/docroot/templates/master_templates/master.tmpl line 2
Template::Provider::__ANON__(Template::Context=HASH(0x269d0e0)) called at /usr/local/cpanel/3rdparty/perl/526/lib64/perl5/cpanel_lib/x86_64-linux-64int/Template/Document.pm line 162
eval {...} called at /usr/local/cpanel/3rdparty/perl/526/lib64/perl5/cpanel_lib/x86_64-linux-64int/Template/Document.pm line 160
Template::Document::process(Template::Document=HASH(0x265b1c0), Template::Context=HASH(0x269d0e0)) called at /usr/local/cpanel/3rdparty/perl/526/lib64/perl5/cpanel_lib/x86_64-linux-64int/Template/Context.pm line 357
eval {...} called at /usr/local/cpanel/3rdparty/perl/526/lib64/perl5/cpanel_lib/x86_64-linux-64int/Template/Context.pm line 327
Template::Context::process(Template::Context=HASH(0x269d0e0), "master_templates/master.tmpl", HASH(0x265d3a0), "localize me!") called at /usr/local/cpanel/3rdparty/perl/526/lib64/perl5/cpanel_lib/x86_64-linux-64int/Template/Context.pm line 415
Template::Context::include(Template::Context=HASH(0x269d0e0), "master_templates/master.tmpl", HASH(0x265d3a0)) called at /var/cpanel/template_compiles//usr/local/cpanel/whostmgr/docroot/templates/dialog.tmpl line 56
eval {...} called at /var/cpanel/template_compiles//usr/local/cpanel/whostmgr/docroot/templates/dialog.tmpl line 1
Template::Provider::__ANON__(Template::Context=HASH(0x269d0e0)) called at /usr/local/cpanel/3rdparty/perl/526/lib64/perl5/cpanel_lib/x86_64-linux-64int/Template/Document.pm line 162
eval {...} called at /usr/local/cpanel/3rdparty/perl/526/lib64/perl5/cpanel_lib/x86_64-linux-64int/Template/Document.pm line 160
Template::Document::process(Template::Document=HASH(0x265c980), Template::Context=HASH(0x269d0e0)) called at /usr/local/cpanel/3rdparty/perl/526/lib64/perl5/cpanel_lib/x86_64-linux-64int/Template/Context.pm line 357
eval {...} called at /usr/local/cpanel/3rdparty/perl/526/lib64/perl5/cpanel_lib/x86_64-linux-64int/Template/Context.pm line 327
Template::Context::process(Template::Context=HASH(0x269d0e0), Template::Document=HASH(0x265c980)) called at /usr/local/cpanel/3rdparty/perl/526/lib64/perl5/cpanel_lib/x86_64-linux-64int/Template/Service.pm line 94
eval {...} called at /usr/local/cpanel/3rdparty/perl/526/lib64/perl5/cpanel_lib/x86_64-linux-64int/Template/Service.pm line 91
Template::Service::process(Template::Service=HASH(0x269cca8), "dialog.tmpl", HASH(0x269c4c8)) called at /usr/local/cpanel/3rdparty/perl/526/lib64/perl5/cpanel_lib/x86_64-linux-64int/Template.pm line 64
Template::process(Template=HASH(0x269c930), "dialog.tmpl", HASH(0x269c4c8)) called at /usr/local/cpanel/Cpanel/Template.pm line 465
Cpanel::Template::process_template("whostmgr", HASH(0x269c4c8)) called at whostmgr/bin/whostmgr.pl line 4347
main::dialog("dialog") called at /usr/local/cpanel/Whostmgr/Dispatch.pm line 259
Whostmgr::Dispatch::_do_call("dialog", HASH(0x26745a0), HASH(0x2691610)) called at /usr/local/cpanel/Whostmgr/Dispatch.pm line 157
Whostmgr::Dispatch::dispatch("dialog", 1, ARRAY(0x2691508), HASH(0x2691610)) called at whostmgr/bin/whostmgr.pl line 408

Please help me in solving the issues. Thank you.
 

avinash.pudota

Active Member
Jan 27, 2013
26
2
3
India
cPanel Access Level
Root Administrator
@marcuszan
Thank you for your help.

the above file has errors logged but i cant understand it, below are last few lines
Code:
DBG: 21052: Wed Dec 12 13:34:27 2018: command line: --default-kernel
DBG: Image entry failed: uuid missing: rootdev (null), dev 5afa4f9a-3063-42c5-87a2-30d66c619a16
DBG: menuentry 'CentOS Linux (3.10.0-862.14.4.el7.x86_64) 7 (Core)' --class centos --class gnu-linux --class gnu --class os --unrestricted $menuentry_id_option 'gnulinux-3.10.0-693.21.1.el7.x86_64-advanced-5afa4f9a-3063-42c5-87a2-30d66c619a16' {
DBG:     load_video
DBG:     set gfxpayload=keep
DBG:     insmod gzio
DBG:     insmod part_gpt
DBG:     insmod part_gpt
DBG:     insmod diskfilter
DBG:     insmod mdraid09
DBG:     insmod ext2
DBG:     set root='mduuid/a66932bf6600cd22a4d2adc226fd5302'
DBG:     if [ x$feature_platform_search_hint = xy ]; then
DBG:       search --no-floppy --fs-uuid --set=root --hint='mduuid/a66932bf6600cd22a4d2adc226fd5302'  139a0398-8e80-46e8-bf4f-781a2975e25e
DBG:     else
DBG:       search --no-floppy --fs-uuid --set=root 139a0398-8e80-46e8-bf4f-781a2975e25e
DBG:     fi
DBG:     linuxefi /vmlinuz-3.10.0-862.14.4.el7.x86_64 root=/dev/md3 ro crashkernel=auto rhgb quiet rd.md.uuid=dd1cafb8:967fe6e4:a4d2adc2:26fd5302 rd.md.uuid=a66932bf:6600cd22:a4d2adc2:26fd5302 rootdelay=10 rootdelay=10 LANG=en_US.UTF-8
DBG:     initrdefi /initramfs-3.10.0-862.14.4.el7.x86_64.img
DBG: }
DBG: 31474: Wed Dec 12 14:08:25 2018: command line: --default-kernel
DBG: Image entry failed: uuid missing: rootdev (null), dev 5afa4f9a-3063-42c5-87a2-30d66c619a16
DBG: menuentry 'CentOS Linux (3.10.0-862.14.4.el7.x86_64) 7 (Core)' --class centos --class gnu-linux --class gnu --class os --unrestricted $menuentry_id_option 'gnulinux-3.10.0-693.21.1.el7.x86_64-advanced-5afa4f9a-3063-42c5-87a2-30d66c619a16' {
DBG:     load_video
DBG:     set gfxpayload=keep
DBG:     insmod gzio
DBG:     insmod part_gpt
DBG:     insmod part_gpt
DBG:     insmod diskfilter
DBG:     insmod mdraid09
DBG:     insmod ext2
DBG:     set root='mduuid/a66932bf6600cd22a4d2adc226fd5302'
DBG:     if [ x$feature_platform_search_hint = xy ]; then
DBG:       search --no-floppy --fs-uuid --set=root --hint='mduuid/a66932bf6600cd22a4d2adc226fd5302'  139a0398-8e80-46e8-bf4f-781a2975e25e
DBG:     else
DBG:       search --no-floppy --fs-uuid --set=root 139a0398-8e80-46e8-bf4f-781a2975e25e
DBG:     fi
DBG:     linuxefi /vmlinuz-3.10.0-862.14.4.el7.x86_64 root=/dev/md3 ro crashkernel=auto rhgb quiet rd.md.uuid=dd1cafb8:967fe6e4:a4d2adc2:26fd5302 rd.md.uuid=a66932bf:6600cd22:a4d2adc2:26fd5302 rootdelay=10 rootdelay=10 LANG=en_US.UTF-8
DBG:     initrdefi /initramfs-3.10.0-862.14.4.el7.x86_64.img
DBG: }
DBG: 12276: Wed Dec 12 14:48:56 2018: command line: --default-kernel
DBG: Image entry failed: uuid missing: rootdev (null), dev 5afa4f9a-3063-42c5-87a2-30d66c619a16
DBG: menuentry 'CentOS Linux (3.10.0-862.14.4.el7.x86_64) 7 (Core)' --class centos --class gnu-linux --class gnu --class os --unrestricted $menuentry_id_option 'gnulinux-3.10.0-693.21.1.el7.x86_64-advanced-5afa4f9a-3063-42c5-87a2-30d66c619a16' {
DBG:     load_video
DBG:     set gfxpayload=keep
DBG:     insmod gzio
DBG:     insmod part_gpt
DBG:     insmod part_gpt
DBG:     insmod diskfilter
DBG:     insmod mdraid09
DBG:     insmod ext2
DBG:     set root='mduuid/a66932bf6600cd22a4d2adc226fd5302'
DBG:     if [ x$feature_platform_search_hint = xy ]; then
DBG:       search --no-floppy --fs-uuid --set=root --hint='mduuid/a66932bf6600cd22a4d2adc226fd5302'  139a0398-8e80-46e8-bf4f-781a2975e25e
DBG:     else
DBG:       search --no-floppy --fs-uuid --set=root 139a0398-8e80-46e8-bf4f-781a2975e25e
DBG:     fi
DBG:     linuxefi /vmlinuz-3.10.0-862.14.4.el7.x86_64 root=/dev/md3 ro crashkernel=auto rhgb quiet rd.md.uuid=dd1cafb8:967fe6e4:a4d2adc2:26fd5302 rd.md.uuid=a66932bf:6600cd22:a4d2adc2:26fd5302 rootdelay=10 rootdelay=10 LANG=en_US.UTF-8
DBG:     initrdefi /initramfs-3.10.0-862.14.4.el7.x86_64.img
DBG: }
DBG: 25716: Wed Dec 12 15:26:06 2018: command line: --default-kernel
DBG: Image entry failed: uuid missing: rootdev (null), dev 5afa4f9a-3063-42c5-87a2-30d66c619a16
DBG: menuentry 'CentOS Linux (3.10.0-862.14.4.el7.x86_64) 7 (Core)' --class centos --class gnu-linux --class gnu --class os --unrestricted $menuentry_id_option 'gnulinux-3.10.0-693.21.1.el7.x86_64-advanced-5afa4f9a-3063-42c5-87a2-30d66c619a16' {
DBG:     load_video
DBG:     set gfxpayload=keep
DBG:     insmod gzio
DBG:     insmod part_gpt
DBG:     insmod part_gpt
DBG:     insmod diskfilter
DBG:     insmod mdraid09
DBG:     insmod ext2
DBG:     set root='mduuid/a66932bf6600cd22a4d2adc226fd5302'
DBG:     if [ x$feature_platform_search_hint = xy ]; then
DBG:       search --no-floppy --fs-uuid --set=root --hint='mduuid/a66932bf6600cd22a4d2adc226fd5302'  139a0398-8e80-46e8-bf4f-781a2975e25e
DBG:     else
DBG:       search --no-floppy --fs-uuid --set=root 139a0398-8e80-46e8-bf4f-781a2975e25e
DBG:     fi
DBG:     linuxefi /vmlinuz-3.10.0-862.14.4.el7.x86_64 root=/dev/md3 ro crashkernel=auto rhgb quiet rd.md.uuid=dd1cafb8:967fe6e4:a4d2adc2:26fd5302 rd.md.uuid=a66932bf:6600cd22:a4d2adc2:26fd5302 rootdelay=10 rootdelay=10 LANG=en_US.UTF-8
DBG:     initrdefi /initramfs-3.10.0-862.14.4.el7.x86_64.img
DBG: }

As this is a live server with a couple of domains, i need to wait until the traffic is low.

I am afraid that, making any changes in grub would cause any issue to netboot feature of OVH, currently it is a life saver for me. i was able to boot into server even when the harddisk kernel caused issue.

Also, i am not sure if the server is using BIOS or EFI boot, how do i find that.

Which command should i use from the below two to rebuild grub
Code:
grub2-mkconfig -o /boot/grub2/grub.cfg
grub2-mkconfig -o /boot/efi/EFI/centos/grub.cfg
There is another thread with similar issue, but rebuild grub did not solve the issue for them.
Grub error after update from 7.5 to 7.6 - CentOS
 
Last edited:

marcuszan

Well-Known Member
Apr 19, 2018
63
5
8
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cPanel Access Level
Root Administrator
@avinash.pudota

your grub indicates >
linuxefi

this is same as on my box, there for I tried to rebuild >
Code:
grub2-mkconfig -o /boot/efi/EFI/centos/grub.cfg
I think whatever you mess around with grub , you will always be able to use the netboot kernel image from OVH.
I am not 100% sure, but I think so. Maybe check with OVH support to be sure
 

avinash.pudota

Active Member
Jan 27, 2013
26
2
3
India
cPanel Access Level
Root Administrator
Thank you for the info.

I ran the command "grub2-mkconfig -o /boot/efi/EFI/centos/grub.cfg"
and here is the output. The file is also created at /boot/efi/EFI/centos/grub.cfg. However i didn't yet restart the server yet.
Code:
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-3.10.0-862.14.4.el7.x86_64
Found initrd image: /boot/initramfs-3.10.0-862.14.4.el7.x86_64.img
Found linux image: /boot/vmlinuz-3.10.0-862.11.6.el7.x86_64
Found initrd image: /boot/initramfs-3.10.0-862.11.6.el7.x86_64.img
Found linux image: /boot/vmlinuz-3.10.0-862.9.1.el7.x86_64
Found initrd image: /boot/initramfs-3.10.0-862.9.1.el7.x86_64.img
Found linux image: /boot/vmlinuz-3.10.0-862.3.2.el7.x86_64
Found initrd image: /boot/initramfs-3.10.0-862.3.2.el7.x86_64.img
Found linux image: /boot/vmlinuz-3.10.0-862.2.3.el7.x86_64
Found initrd image: /boot/initramfs-3.10.0-862.2.3.el7.x86_64.img
Found linux image: /boot/vmlinuz-0-rescue-485ccf091d93c1ef5d85bdf65ab397a6
Found initrd image: /boot/initramfs-0-rescue-485ccf091d93c1ef5d85bdf65ab397a6.img
Found linux image: /boot/vmlinuz-0-rescue-1e98a4cc1263468b9f9a12e365316b95
Found initrd image: /boot/initramfs-0-rescue-1e98a4cc1263468b9f9a12e365316b95.img
done
 

marcuszan

Well-Known Member
Apr 19, 2018
63
5
8
Netherlands
cPanel Access Level
Root Administrator
@avinash.pudota
for me this solved the issue. I would suggest to be 100% safe to ask OVH support if the netboot will work even when you complete mess up your grub on HDD.
If they confirm, you have nothing to loose to give it a try and reboot from HDD.
If it doesnt come up, change the boot in your OVH manager back to the netboot and reboot the server from the OVH manager panel.

Let us know if it works ;-)
 
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marcuszan

Well-Known Member
Apr 19, 2018
63
5
8
Netherlands
cPanel Access Level
Root Administrator
OVH booted it for me from Net boot. I haven't restarted it since.
There should be a grub file / folder somewhere that you can check when booted on OVH netboot kernel. The HDD files are accesible as usual, you only used the OVH kernel to boot up. The original faulting grub is still somewhere on your HDD

Check instructions here
HowTos/Grub2 - CentOS Wiki
 

Benjamin D.

Well-Known Member
Jan 28, 2016
128
17
68
Canada
cPanel Access Level
Root Administrator
This morning I decided to upgrade from WHM v74.0.9 to WHM v74.0.12 because of a bunch of security fixes. After the upgrade was successful, it popped in the top/right corner that it needed to gracefully reboot my server so clicked on the link and confirmed the graceful reboot.

My server never came back. Totally unpingable, no SSH access, nothing.

The data center has been investigating over the last 15 minutes and still going.

How can an update like this cause the whole server to go down and never come back up?! WTF
 
Last edited:

avinash.pudota

Active Member
Jan 27, 2013
26
2
3
India
cPanel Access Level
Root Administrator
@avinash.pudota
for me this solved the issue. I would suggest to be 100% safe to ask OVH support if the netboot will work even when you complete mess up your grub on HDD.
If they confirm, you have nothing to loose to give it a try and reboot from HDD.
If it doesnt come up, change the boot in your OVH manager back to the netboot and reboot the server from the OVH manager panel.

Let us know if it works ;-)

Rebooted server via Disk, and it booted successfully, it also resolved a couple of issues which i had when i used netboot.
1.) Warnings in security adviser are gone, after booting from disk kernel, there was an recommendation for updated kernel, kernel was updated and rebooted again without any issues.
2.) Disk Quotas was not functioning properly when server was on netboot, all newly created accounts defaulted to unlimited quota, and it throws error when we try to edit it. even i was unable to change quota for existing account. it was fixed now.

The command which solved the issue was

grub2-mkconfig -o /boot/efi/EFI/centos/grub.cfg
 
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Reactions: marcuszan

avinash.pudota

Active Member
Jan 27, 2013
26
2
3
India
cPanel Access Level
Root Administrator
This morning I decided to upgrade from WHM v74.0.9 to WHM v74.0.12 because of a bunch of security fixes. After the upgrade was successful, it popped in the top/right corner that it needed to gracefully reboot my server so clicked on the link and confirmed the graceful reboot.

My server never came back. Totally unpingable, no SSH access, nothing.

The data center has been investigating over the last 15 minutes and still going.

How can an update like this cause the whole server to go down and never come back up?! WTF
It is a centos issue which happened with the centos 7.6 update
Mostly, you need to disable SELinux and/or fix grub from console/KVM and reboot. If you have netboot option reboot via netboot, fix the issue and reboot again from disk.
 

marcuszan

Well-Known Member
Apr 19, 2018
63
5
8
Netherlands
cPanel Access Level
Root Administrator
It is a centos issue which happened with the centos 7.6 update
Mostly, you need to disable SELinux and/or fix grub from console/KVM and reboot. If you have netboot option reboot via netboot, fix the issue and reboot again from disk.
Agree,

Disable SELinux as described above and fix UEFI grub, as this seems to be introduced in CentOS 7.6 by using >
grub2-mkconfig -o /boot/efi/EFI/centos/grub.cfg
 

dahu

Member
Dec 7, 2001
23
2
303
(january 17 2019)

Just a solution for the OVH one that goes the same problem and panic day...

today i done the "reboot for system update" from WHM (centos 7)

so, as completly unexpected, my Server go to brick (no boot again), a good big brick :(

after 6 hours :
- asking OVH saying 'look at IMPI" (grub prompt in the empty intersideral space)
then saying " go to rescue mode "
then saying "ask Cpanel support"
-asking cpanel saying : Its not a problem from Cpanel/whm update, so look with a sysadmin

looking at the empty directory /boot etc. ect. , look at the selinux etc.

Then, i go to my OVH dashboard and tryed : netboot : stable kernel

and all was back
 

marcuszan

Well-Known Member
Apr 19, 2018
63
5
8
Netherlands
cPanel Access Level
Root Administrator
(january 17 2019)

Just a solution for the OVH one that goes the same problem and panic day...

today i done the "reboot for system update" from WHM (centos 7)

so, as completly unexpected, my Server go to brick (no boot again), a good big brick :(

after 6 hours :
- asking OVH saying 'look at IMPI" (grub prompt in the empty intersideral space)
then saying " go to rescue mode "
then saying "ask Cpanel support"
-asking cpanel saying : Its not a problem from Cpanel/whm update, so look with a sysadmin

looking at the empty directory /boot etc. ect. , look at the selinux etc.

Then, i go to my OVH dashboard and tryed : netboot : stable kernel

and all was back
Booting with netboot kernel is a way to get your machine up again, but it does not repair the stuff that got broken and caused your server to hang at boot.
After booting with netboot kernel you will be able to try to fix the original problem, so when this is fixed you can switch back to HDD boot again in OVH panel.
 

dahu

Member
Dec 7, 2001
23
2
303
i tryed (selinux is already on disable)
grub2-mkconfig -o /boot/grub2/grub.cfg
grub2-mkconfig -o /boot/efi/EFI/centos/grub.cfg

and it doesnt solved the prob on hdd reboot: im stuck on grub with the choose system, no timer
when i choose my kernel i got "could not find command "linux" , press a key...

the good bzimage is in the /boot
the grub.cfg for grub2 and efi seems well generated

any idea ?
 

marcuszan

Well-Known Member
Apr 19, 2018
63
5
8
Netherlands
cPanel Access Level
Root Administrator
i tryed (selinux is already on disable)
grub2-mkconfig -o /boot/grub2/grub.cfg
grub2-mkconfig -o /boot/efi/EFI/centos/grub.cfg

and it doesnt solved the prob on hdd reboot: im stuck on grub with the choose system, no timer
when i choose my kernel i got "could not find command "linux" , press a key...

the good bzimage is in the /boot
the grub.cfg for grub2 and efi seems well generated

any idea ?
check /var/log/grubby for errors
 

dahu

Member
Dec 7, 2001
23
2
303
no errors, i do not succesfull boot on hdd from 24hours (im on netboot) and i get this for today :


DBG: 10919: Fri Jan 18 12:12:39 2019: command line: --default-kernel
DBG: Image entry succeeded:
DBG: menuentry 'GNU/Linux with OVH Kernel, OVH kernel 4.9.87-xxxx-std-ipv6-64' {
DBG: load_video
DBG: set gfxpayload=keep
DBG: insmod part_gpt
DBG: insmod part_gpt
DBG: insmod diskfilter
DBG: insmod mdraid09
DBG: insmod ext2
DBG: set root='mduuid/2fbcdcf2f2dde0c4a4d2adc226fd5302'
DBG: if [ x$feature_platform_search_hint = xy ]; then
DBG: search --no-floppy --fs-uuid --set=root --hint='mduuid/2fbcdcf2f2dde0c4a4d2adc226fd5302' 09c4d
bce-1565-42ce-a0b2-2a1179a74bdc
DBG: else
DBG: search --no-floppy --fs-uuid --set=root 09c4dbce-1565-42ce-a0b2-2a1179a74bdc
DBG: fi
DBG: linux /bzImage-4.9.87-xxxx-std-ipv6-64 root=/dev/md3 ro crashkernel=auto rhgb quiet rootde
lay=10
DBG: }