Google's Compute Engine along with Google Cloud SQL are down according to the status page. There is no indication of what exactly went wrong besides basic reports of network connectivity loss. Other cloud services appear to be working fine, although Google Cloud SQL has now been experiencing issues for over a day.
Although the time shown in the screenshot above is listed as 2015-02-19 15:59, it appears to be inaccurate. The accurate time is actually 2015-02-18 22:59. Times are US/Pacific.
Google has taken some steps to bring more features into their Cloud platform, including adding things like Windows support, but this sort of issue is problematic for Google who has been trying to compete with Amazon's AWS. When it comes to cloud services, uptime is everything, and it's important in the very least to keep customers informed on what is going wrong when downtime occurs.
As of 0:50 US/Pacific time, the services are still down.
Update: All services have been restored as of after 01:00 PT, with Google making the following statement:
The problem with network connectivity in Google Compute Engine is resolved as of shortly after 01:00 US/Pacific. We are sorry for any issues this may have caused to you or your users and thank you for your patience and continued support. Please rest assured that system reliability is a top priority at Google, and we are constantly working to improve the reliability of our systems.
We will provide a detailed analysis of this incident once we have completed our internal investigation.