Warning: SPOILERS for Thor: Ragnarok are ahead!
If you were keeping an eye out for Easter eggs when watching 2011's Thor, you no doubt noticed that one of the prizes in Odin's treasure room was the Infinity Gauntlet. Four years later, Avengers: Age of Ultron showed Thanos retrieving another Infinity Gauntlet from his vault, and Marvel Studios president Kevin Feige later clarified that there are two Infinity Gauntlets in the MCU. However, it was revealed in Thor: Ragnarok that the Infinity Gauntlet on Asgard is a fake, and according to director Taika Waititi, the reason Odin kept that prop around was so that others wouldn't go looking for the real deal. Waititi explained to CinemaBlend's own Eric Eisenberg:
That came about because in Thor 1, the reason that it's in this movie is because someone who went through that movie, frame by frame, looking for Easter eggs was like 'Oh! The Infinity Gauntlet!' And then from that point on, they were like, 'That damn Infinity Gauntlet, what are we going to do with that thing?' It's like, there, but it also [exists] somewhere else in the universe. How do we deal with that? And then we realized like, Odin... Hela goes through and she goes, 'Fake. All of that stuff that's in here is fake.' Basically the thing we were trying to go for was that Odin somewhere along the line realized that everyone knew that the Infinity Gauntlet was on Asgard and in the safe keeping of Odin, then no one would come looking for it. So he made a fake one, and let everyone believe... Basically, a fake launch code.
So there you have it. Just like in the comics, there's only one Infinity Gauntlet floating around the MCU, and unfortunately, Thanos possesses it. This revelation came when Hela was walking through Odin's treasure room with Skurge and declared that most of the items within were fake, specifically stopping at the prop Infinity Gauntlet when saying this. But along with this information playing into Thor: Ragnarok's main story, the threequel's co-writer, Eric Pearson, told CinemaBlend that this retcon also worked as a way to help Christopher Markus and Stephen McFeely, the duo writing Avengers: Infinity War and Avengers 4. As Pearson put it:
We brought that over -- like here's an opportunity to take something off the plate of Markus and McFeely, who are doing Avengers 3 and 4, and have plenty else to worry about with I don't know -- what -- 60-plus characters in one movie?
While there were a few legitimate prizes in Odin's treasure room, like the Eternal Flame and the Tesseract, for the most part the All-Father's collection was filled with duds, all of which (aside from the Tesseract) were destroyed when Surtur laid waste to Asgard. As for the real Infinity Gauntlet, Thanos is carrying it around with him now, and he'll attempt to place all six Infinity Stones onto it during Avengers: Infinity War and possibly Avengers 4.