Erroneously, availability_zone for host aggregate resource types was
considered mandatory in heat templates. It is now optional.
Heat can now perform a stack update to roll back to a previous version of a
resource after a previous attempt to create a replacement for it failed.
Empty string passing in for volume availability_zone can be correctly handled
now. For this case, it’s same as no AZ set, so the default AZ in cinder.conf
will be used.
Non-ASCII text that appears in parameter constraints (e.g. in the description
of a constraint, or a list of allowed values) will now be handled correctly
when generating error messages if the constraint is not met.
OS::Neutron::Port resources will now be replaced when the mac_address
property is modified. Neutron is unable to update the MAC address of a port
once the port is in use.
