OVH gives you a /128 block by default. But in fact you can use the whole /64. You can simply add a /64 address to eth0.
But if you activate IPv6 in docker and try to allocate an address in bridge network, you will find the address is not ping-able. The problem here is we should send a NDP notification to OVH router.
配置OVH的獨服在docker中使用IPv6
OVH的機器默認給的是/128，但是其實整個/64都是可以用的，如果添加到網卡上是可以雙向ping通的。
但是如果docker的bridge網路分配了一個IPv6，卻無法ping通。喝了一瓶果汁之後我發現是因為沒有向（OVH的）路由器發鄰居發現協議包（NDP）。
