持久化配置
创建网络配置文件
nano /etc/network/interfaces.d/51-cloud-init-ipv6文件内容：
auto eth0
iface eth0 inet6 static
mtu 1500
address YOUR_IPV6
netmask IPV6_PREFIX**（64）**
post-up /sbin/ip -6 route add IPV6_GATEWAY dev eth0
post-up /sbin/ip -6 route add default via IPV6_GATEWAY dev eth0
pre-down /sbin/ip -6 route del default via IPV6_GATEWAY dev eth0
pre-down /sbin/ip -6 route del IPV6_GATEWAY dev eth0重启网络
service networking restart