Grids are becoming a mission-critical component in research and industry. The services they provide are thus required to be highly available, contributing to the vision of the grid as a dependable virtual computer of infinite power. However, building highly available services in grid is particularly difficult due to the unique characteristics of the grid environment. We believe that high availability functionality should itself be provided as a service, which can be used by transparently decorating, but not changing, the original services, thus making them highly available. In this work we highlight the major challenges and describe our initial experience in building such a generic high availability service in the context of the Condor system