What are germany and austria hungary bound to do for one another

Germany and Austria Hungary are good alliances, when one get's a war the other also fights that war with them.

The Triple Alliance or Triplice was a secret agreement between Germany, Austria-Hungary, and Italy. It was formed on 20 May 1882 and renewedperiodically until it expired in 1915 during World War I. Germany and Austria-Hungary had been closelyallied since 1879.

Why they did what they did:

Germany, Austria-Hungary and Italy formed the Triple Alliance. In 1882, they signed a document that promised they would give each other military support in case of a war. The Alliance agreement stated it was 'essentially defensive and conservative' with the aim of stopping anyone who 'might threaten' the three nations.