Create OpenStack DualStack or IPv6 only VM 

# Create router
openstack router create test-router1 \
  --centralized \
  --ha \
  --external-gateway public

# Show available tenant IPv6 subnet
openstack subnet pool list --share | grep tenant-subnet-pool-v6

# Create network
openstack network create test-network1

# DUAL-STACK: Create IPv4 subnet (skip for IPv6 only)
openstack subnet create test-subnet1-ipv4 \
  --network test-network1 \
  --subnet-range 10.11.12.0/24

# DUAL-STACK: Attach IPv4 subnet to router (skip for IPv6 only)
openstack router add subnet test-router1 test-subnet1-ipv4

# Create IPv6 subnet
openstack subnet create test-subnet1-ipv6 \
  --network test-network1 \
  --ip-version 6 \
  --subnet-pool tenant-subnet-pool-v6 \
  --prefix-length 64 \
  --ipv6-ra-mode dhcpv6-stateless \
  --ipv6-address-mode dhcpv6-stateless

# Attach IPv6 subnet to router
openstack router add subnet test-router1 test-subnet1-ipv6

# OPTINAL: allow access from outside
SECURITY_GROUP=test-secgroup
openstack security group create ${SECURITY_GROUP}

# DUAL-STACK: allow access to Floating FIP from outside (skip for IPv6 only)
openstack security group rule create ${SECURITY_GROUP} --ethertype IPv4 --protocol icmp --ingress --remote-ip 0.0.0.0/0
openstack security group rule create ${SECURITY_GROUP} --ethertype IPv4 --protocol icmp --egress --remote-ip 0.0.0.0/0
openstack security group rule create ${SECURITY_GROUP} --ethertype IPv4 --protocol tcp --dst-port 22 --remote-ip 0.0.0.0/0
ipv6