kernel config environment variables needed to be enabled to support CRIU. Run `grep -f criu_env.txt /boot/config-version` to check.

CONFIG_EXPERT
CONFIG_EMBEDDED
CONFIG_CHECKPOINT_RESTORE
CONFIG_NAMESPACES
CONFIG_UTS_NS
CONFIG_IPC_NS
CONFIG_PID_NS
CONFIG_NET_NS
CONFIG_FHANDLE
CONFIG_EVENTFD
CONFIG_EPOLL
CONFIG_INOTIFY_USER
CONFIG_IA32_EMULATION
CONFIG_UNIX_DIAG
CONFIG_INET_DIAG
CONFIG_INET_UDP_DIAG
CONFIG_PACKET_DIAG
CONFIG_NETLINK_DIAG
CONFIG_MEM_SOFT_DIRTY
CONFIG_NET_PKTGEN