RHEL 9 unable to boot with memory set more than 32GB

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sysadminptsb

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Oct 9, 2024
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VM Settings:
vCPU: 4
Memory: 32GB
OS: RHEL9

Issue: VM not able to boot with kernel panic error if memory set to 32GB, but if memory set =< 28GB then VM able to boot normally. Please refer attachments.

Action taken:
1) edit /etc/default/grub, add memhp_default_state=online in GRUB_CMDLINE_LINUX
run # grub2-mkconfig -o /boot/grub2/grub.cfg and reboot
(Result = VM not able to up)

2) Change processors type = host
(Result = VM not able to up)

3)Disable NUMA, Disable hotplug for memory & cpu.
(Result = VM able to up)

Please help advise which config need to change to ensure vm able to boot with NUMA & hotplug enabled.
 

Attachments

  • 32gbvm.png
    32gbvm.png
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  • kernelpanic.png
    kernelpanic.png
    146.5 KB · Views: 15
Seems to be something very RedHat specific... Ubuntu runs normally with it.
Which Kernel version does your RHEL use?
 
Virtualization: kvm
Operating System: Red Hat Enterprise Linux 9.4 (Plow)
CPE OS Name: cpe:/o:redhat:enterprise_linux:9::baseos
Kernel: Linux 5.14.0-427.37.1.el9_4.x86_64
Architecture: x86-64
Hardware Vendor: QEMU
Hardware Model: Standard PC _Q35 + ICH9, 2009_
Firmware Version: rel-1.16.2-0-gea1b7a073390-prebuilt.qemu.org
 
sysadminptsb said:
Virtualization: kvm
Operating System: Red Hat Enterprise Linux 9.4 (Plow)
CPE OS Name: cpe:/o:redhat:enterprise_linux:9::baseos
Kernel: Linux 5.14.0-427.37.1.el9_4.x86_64
Architecture: x86-64
Hardware Vendor: QEMU
Hardware Model: Standard PC _Q35 + ICH9, 2009_
Firmware Version: rel-1.16.2-0-gea1b7a073390-prebuilt.qemu.org
Click to expand...
This should basically work... do you have an ISO for me where I can test this?
 
I've tested an Rocky Linux 9.4, what is normally the same like Rhel.
Kernel 5.14.0-427.18.1.el9_4.x86_64

I've configured 32, 36, 40GB Memory. And it was working fine. But i had this machine configured with UEFI and TPM. Unfortunately, I don't know if it has anything to do with that, but I could imagine that with Rhel.
 
Could now download and install a Rhel directly. Also works here with 36GB as it should.
Kernel 5.14.0-427.40.1.el9_4.x86_64.

Code: 
agent: 1
bios: ovmf
boot: order=scsi0
cores: 6
cpu: host
efidisk0: SSD-vmdata:vm-164-disk-0,efitype=4m,size=1M
ide2: none,media=cdrom
machine: q35
memory: 36864
meta: creation-qemu=9.0.2,ctime=1729108892
name: rhel-efi
net0: virtio=BE:24:11:3E:72:A1,bridge=vlan50,firewall=1
numa: 1
ostype: l26
scsi0: SSD-vmdata:vm-164-disk-1,discard=on,iothread=1,size=32G,ssd=1
scsihw: virtio-scsi-single
sockets: 1
tpmstate0: SSD-vmdata:vm-164-disk-2,size=4M,version=v2.0
vga: virtio
 
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Hi, we've found solution for this issue, apparently the kernel does not load the grub using the usual RHEL8 method:

RHEL8:
1) edit /etc/default/grub, add memhp_default_state=online in GRUB_CMDLINE_LINUX
2) run # grub2-mkconfig -o /boot/grub2/grub.cfg
3) reboot

for RHEL9 please use :
1) grubby --update-kernel=/boot/vmlinuz-$(uname -r) --args="memhp_default_state=online"
2) reboot
3) cat /proc/cmdline // to verify
expected output = BOOT_IMAGE=(hd0,gpt1)/vmlinuz-5.14.0-427.37.1.el9_4.x86_64 root=/dev/mapper/rhel-root ro crashkernel=1G-4G:192M,4G-64G:256M,64G-:512M resume=/dev/mapper/rhel-swap rd.lvm.lv=rhel/root rd.lvm.lv=rhel/swap memhp_default_state=online

Thanks,
sysadminptsb
 
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sysadminptsb said:
VM Settings:
vCPU: 4
Memory: 32GB
OS: RHEL9

Issue: VM not able to boot with kernel panic error if memory set to 32GB, but if memory set =< 28GB then VM able to boot normally. Please refer attachments.

Action taken:
1) edit /etc/default/grub, add memhp_default_state=online in GRUB_CMDLINE_LINUX
run # grub2-mkconfig -o /boot/grub2/grub.cfg and reboot
(Result = VM not able to up)

2) Change processors type = host
(Result = VM not able to up)

3)Disable NUMA, Disable hotplug for memory & cpu.
(Result = VM able to up)

Please help advise which config need to change to ensure vm able to boot with NUMA & hotplug enabled.
Click to expand...
Hi
Take a look at kove.com as possible memory /rhel solution. ( virt/pool memory ideally on rhel and Openshift )
 
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