Once the server is launched, hit http://localhost:9000. By default, the in-process database (H2, or Derby prior to SonarQube 3.2) is used but you can specify a local MySQL instance instead with the property "-Dsonar.database=mysql". In that case, the sonar schema must exist in the MySQL DB along with the user sonar/sonar (login/password) which must have all rights on the sonar schema.
# Note that SonarQube versions greater than or equal 4.0 are not supported yet mvn install org.codehaus.sonar:sonar-dev-maven-plugin::start -Dsonar.runtimeVersion=3.7.2
Add the property -Djava.io.tmpdir=/tmp to the mvn command.