The Ukrainian broadcaster (NTU) announced on 22 July that they had shortlisted three cities to host the contest in 2017. They are Kyiv, Dnipro and Odessa. A final decision will be made by 1 August.
At this stage there isn't really a clear front runner from the three cities. All of their bids have both strengths and weaknesses. There are a number of criteria the host city needs to meet - from having an appropriate (and available!) venue, sufficient hotel rooms and appropriate transport networks (both in the selected city and with international destinations to bring in participants and fans)
Between now and August 1st officials will be visiting the three shortlisted cities to inspect their facilities. It is expected that they will confirm the dates for the 2017 contest at the same time they announce the host city (it is currently tentatively scheduled for 9, 11 and 13 May 2017).