There are no obligations, just necessities. Without the bailout, Greece would have defaulted and (it was feared) the French/German/Spanish banks that had financed the Greek debt would have fallen as well.
It's worse than simply "no obligations". EU and ECB bailouts of EU member states were specifically forbidden under the Treaty of Lisbon http://euwiki.org/TFEU#Article_123http://euwiki.org/TFEU#Article_125 . Instead, not only did both the EU and the ECB prop up Greece's borrowing, they moved to block Greece's access to a normal IMF program, which would have involved losses for non-IMF creditors.