The HA property is updateable in the UI, however, Neutron API does not allow the update operation because toggling HA support does not work. https://bugs.launchpad.net/horizon/+bug/1378525
HA 属性は UI で更新可能ですが、変更自体は l3-agent では失敗します。 https://bugs.launchpad.net/horizon/+bug/1378525