OpsGuide/Determining Which Component Is Broken

OpenStack’s collection of different components interact with each other strongly. For example, uploading an image requires interaction from,  ,  , keystone, and potentially. As a result, it is sometimes difficult to determine exactly where problems lie. Assisting in this is the purpose of this section.

Tailing Logs
The first place to look is the log file related to the command you are trying to run. For example, if  is failing, try tailing a nova log file and running the command again:

Terminal 1:

Terminal 2:

Look for any errors or traces in the log file. For more information, see Logging and Monitoring.

If the error indicates that the problem is with another component, switch to tailing that component’s log file. For example, if nova cannot access glance, look at the  log:

Terminal 1:

Terminal 2:

Wash, rinse, and repeat until you find the core cause of the problem.

Running Daemons on the CLI
Unfortunately, sometimes the error is not apparent from the log files. In this case, switch tactics and use a different command; maybe run the service directly on the command line. For example, if the  service refuses to start and stay running, try launching the daemon from the command line:

This might print the error and cause of the problem.