Not at all. Employers don't know much about you, so they can only base it on what you wrote your thesis on and what internships you have done in the past. The candidates I like have either have a relevant thesis topic or have done internships in the industry at places like Cisco/Netapps/Oracle etc and have a better understanding of what they want to do.
Cloud is a very broad term. There are many companies doing different things with cloud. My company is moving storage into the cloud. Other companies are doing distributed computing using a cloud of computers (Facebook, Google etc). There's a project called Hadoop that's really hot right now for distributed computing (written in Java) that'll land you jobs. Then there are companies that use the cloud for centralized extranet management. Do talk to your prof on topics.
Networking ties in with cloud quite well since it's how you talk to the cloud servers and move data back and forth. Database not so much. Searchable data tend to be in-house so the search latency won't be too high.
Don't worry about the interviews. It's good to go through many interviews (and fail at them) so you won't be too nervous down the road. It's better to fail a few interviews at Yahoo/Google. Then in the future you'll feel (pshhh, these interviews can't be any harder than the crap I went through at Google). Don't let other candidates concern you. There's more than enough positions to go around in the valley.