$ cat /etc/docker/daemon.json 
{
  "ipv6": true,
  "ip6tables": true,
  "experimental": true,
  "fixed-cidr-v6": "fd00::/64",
  "default-address-pools":[
          {"base": "192.168.0.0/16", "size": 24},
          {"base": "fd00::/56", "size": 64}
  ]
}