After installing postgresql in a new Ubuntu 14.04 installation you get the error:
No PostgreSQL clusters exist; see "man pg_createcluster"
and when you try to start the server with:
sudo service postgresql start
you get the error that the server does not exist:
psql: coud not create to server: No such file or directory ...
The solution can be found in the article here, and is to create manually the first cluster by:
sudo pg_createcluster 9.3 main