Why did Poland, Hungary, and East Germany join the Warsaw Pact?

It was the Communist counteraction to NATO (North Atlantic Treaty Organization). The Warsaw Pact came to be seen as quite a potential militaristic threat, as a sign of Communist dominance, and a definite opponent to American capitalism. The signing of the pact became a symbol of Soviet dominance in Eastern Europe.

I would think because they didn't wanna be overthrown or invaded by the soviet, they wanted to have less to do with the war, they wanted peace.