Network slicing provides a way to define logically isolated networks over the same and shared physical infrastructure. This paper departs from previous work defining GST And Network Slice Operator (GANSO), a framework for automating the creation of network slices over SDN architectures, and proposes extensions to support the availability attribute as defined by the GSMA Generic Network Slice Template (GST). This new attribute is integrated and implemented within the GANSO framework, being validated through a set of experimental results.