Unexpected reboot

Hi there!

I am facing a critical issue with my most important customer and seeking your help to investigate this.

My client is running RHEL 7 on a Lenovo SR630, and he is experiencing unexpected reboots of the servers (happened on the 3 of them)

I can't seem to find much in the /var/log/messages when this is happening, except logs from the boot.

I guess it could be related to:
1) HW issue
2) overheating
3) SW issue (I guess something in the kernel like DPDK)

Could you tell me how to investigate those? which logs can I have a look at for each option?

I've attached the var/log/messages when this is happening (see the yellow highlight) and the rsyslog conmf, maybe we can modify this conf to have more logs?