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documentation.suse.com / Documentación de SUSE Linux Enterprise Server / Virtualization Guide / Hypervisor-Independent Features / Creating crash dumps of a VM Guest
Applies to SUSE Linux Enterprise Server 15 SP2

20 Creating crash dumps of a VM Guest

20.1 Introduction

Whenever a VM crashes, it is useful to collect a core dump of the VM memory for debugging and analysis. For physical machines, Kexec and Kdump takes care of collecting crash dumps. For virtual machines, it depends whether the guest is fully virtualized (FV) or paravirtualized (PV).

20.2 Creating crash dumps for fully virtualized machines

To view crash dumps for FV machines, use the same procedures as for physical machines—Kexec and Kdump.

20.3 Creating crash dumps for paravirtualized machines

Unlike with FVs, Kexec/Kdump does not work in paravirtualized machines. Crash dumps of PV guests must be performed by the host tool stack. If using the xl tool stack for Xen domUs, the xl dump-core command will produce the dump. For libvirt-based VM Guests, the virsh dump command provides the same functionality.

You can configure automatic collection of a core dump with the on_crash setting in the configuration of the VM Guest. This setting tells the host tool stack what to do if the VM Guest encounters a crash. The default in both xl and libvirt is destroy. Useful options for automatically collecting a core dump are coredump-destroy and coredump-restart.

20.4 Additional information

  • The difference between fully virtualized and paravirtualized virtual machines is described in Section 1.4, “Virtualization Modes”.

  • Detailed information about Kexec/Kdump mechanism is included in Chapter 18, Kexec and Kdump.

  • Refer to the xl.cfg manual page (man 5 xl.cfg) for more information on the xl configuration syntax.

  • Refer to https://libvirt.org/formatdomain.html#events-configuration for details about the libvirt XML settings.