I am using CentOS 7. I created /etc/crypttab with the linecryptswap    /swap   /dev/urandom    swap,cipher=aes-cbc-essiv:sha256,nofailand /etc/fstab with the line/dev/mapper/cryptswap              none    swap    sw,nofail   0   0After creating the swap file withdd if=/dev/zero of=/swap bs=4M count=200I get the error messagessystemd-cryptsetup[512]: Failed to activate with key file '/dev/urandom': Operation not supportedandsystemd[1]: Timed out waiting for device dev-mapper-cryptswap.device.systemd[1]: Dependency failed for Cryptography Setup for cryptswap.systemd[1]: Dependency failed for /dev/mapper/cryptswap.at reboot.What did I do wrong?
How to use encrypted swap with systemd?
centos;systemd;encryption;swap