Just a small hint :-)

yum install kexec-tools

grep crashkernel= /etc/default/grub
   GRUB_CMDLINE_LINUX="vconsole.font=latarcyrheb-sun16 vconsole.keymap=sg crashkernel=auto console=tty0 console=ttyS0,115200"

grub2-mkconfig -o /boot/grub2/grub.cfg

reboot

systemctl enable kdump.service

systemctl start kdump.service

systemctl status kdump

grep ^path /etc/kdump.conf

   path /var/crash

 

done!