Luminosity Determination in 7 TeV pp Collisions with the ATLAS Detector

The determination of the total integrated luminosity delivered by the LHC to the ATLAS detector is an important measurement that plays a role in many analyses. The measurement methods, calibration procedure, and long-term performance are discussed for the 5.6 fb$^{-1}$ of pp collisions at 7 TeV in 2011. Emphasis is placed on the understanding of systematic uncertainties due to the calibration procedure and to operating conditions in 2011.