When it was almost time for the Jewish Passover, Jesus went up to Jerusalem.
John refers to 3 different Passovers celebrated during the ministry of Jesus (John 2:23, 6:4, 11:55). Thus the ministry of Jesus was at a minimum 2 years in length. The Law required all males to go to Jerusalem to the Temple for the Passover, but not all did. Deut 16:16
John 2:23 Now while he was in Jerusalem at the Passover Feast, many people saw the miraculous signs he was doing and believed in his name.
John 6:4 The Jewish Passover Feast was near.
John 11:55 When it was almost time for the Jewish Passover, many went up from the country to Jerusalem for their ceremonial cleansing before the Passover.
Deut 16:16 Three times a year all your men must appear before the LORD your God at the place he will choose: at the Feast of Unleavened Bread, the Feast of Weeks and the Feast of Tabernacles. No man should appear before the LORD empty-handed: