How To Obtain Vmcore on Xen/KVM Virtual Machines with Virsh

1. Make sure you have libvirt tools installed on your KVM host (dom0 for Xen):

yum install libvirt -y

2. Make sure virsh utility is installed:

virsh --version
2.0.0

3. Login to the Guest OS.

4. Let the VM wait before rebooting on kernel panic:

sysctl kernel.panic=10000 (number of seconds to wait)

5. Wait until the Guest OS is crashed.

6. Gather VM dump with virsh:

virsh dump domain_name --memory-only --format=kdump-zlib

FYI: If your virsh utility doesn’t support --format option, just skip it:

virsh dump domain_name --memory-only

7. Upload the dump onto the dump server.