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Issue
Some Virtual Servers crash with kernel panics on startup on Xen hypervisors to get access to all CPUs of the hypervisor despite the configuration made in the UI.
Environment
OnApp 6.x
Compute resources - Xen
All Linux based Virtual Servers with kernel < 2.6.32
Resolution
- Install a newer kernel >= 2.6.32
In order to install the newer kernel, you may have to boot the Virtual Server in the Recovery mode.
The article below will help you to prepare a chroot environment. Follow steps 1-6.
https://help.onapp.com/hc/en-us/articles/222051288-Manually-Reset-Linux-root-Password-via-Recovery
Cause
Switching to use the libvirt tool stack instead of xl on Xen hypervisors. The XML config is formed in the way that Virtual Servers get access to all CPUs available on the HV but limited to a number set in the UI. It allows supporting hot resize features. However old kernels are unable to serve more than 32 vCPUs that are passed to them.
A virtual server was configured with one core <vcpu current=\"1\">32</vcpu> but on the hypervisor, you may see that actually, the VS got 32 vCPUs:
[root@xenhv~]# xl list
Name ID Mem VCPUs State Time(s)
ioz4zf4wczatn0 6 1024 32 -b---- 13058.3