I lost ip for my VPS after reboot when systemd update from 225 -> 226. I noticed a wired thing is eth0 -> ens3. According to this link, ens is better new name strategy. So I decided to follow this rule. The configuration file of netctl and iptables are updated (all eth0 -> ens3).
Another thing is I found systemd-networkd could be used for statis IP instead of netctl for my VPS. So I uninstall netctl and switch to systemd-networkd.