Alignment of the ATLAS Inner Detector and its Performance in 2012

The alignment of the ATLAS Inner Detector tracking system has been tuned using advanced procedures for the analysis of the LHC sqrt{s}=8 TeV proton-proton collision data taken during 2012. The description of the detector geometry takes care of the relative alignment of the sensing devices and the magnetic field, momentum biases due to systematic deformations, misalignments affecting the reconstructed track parameters and time-dependent displacements occurring due to environmental changes. The procedures applied as well as the performance of the resulting alignment are presented.