Automatically remove /var/log directory from the openstack instance

Hello, During few days we have faced that from the instance /var/log directory log have been removed automatically after the unexpected reboot. We have faced this issue with centos and ubuntu images. Openstack version is rocky and qemu-kvm version 2.12.0 . If anybody has faced the same issue, kindly help us for solving this issue Thanks & Regards Ziaul