Common problems for Compute typically involve misconfigured networking or credentials that are not sourced properly in the environment. Also, most flat networking configurations do not enable ping or ssh from a compute node to the instances running on that node. Another common problem is trying to run 32-bit images on a 64-bit compute node. This section offers more information about how to troubleshoot Compute.

Compute stores a log file for each service in /var/log/nova. For example, nova-compute.log is the log for the nova-compute service. You can set the following options to format log strings for the nova.log module in nova.conf: logging_context_format_string logging_default_format_string If the log level is set to debug, you can also specify logging_debug_format_suffix to append extra formatting. For information about what variables are available for the formatter see: http://docs.python.org/library/logging.html#formatter. You have two options for logging for OpenStack Compute based on configuration settings. In nova.conf, include the logfile option to enable logging. Alternatively you can set use_syslog=1, and then the nova daemon logs to syslog.

The ask.openstack.org site offers a place to ask and answer questions, and you can also mark questions as frequently asked questions. This section describes some errors people have posted previously. We are constantly fixing bugs, so online resources are a great way to get the most up-to-date errors and fixes.

A 403 forbidden error is caused by missing credentials. Through current installation methods, there are basically two ways to get the novarc file. The manual method requires getting it from within a project zipfile, and the scripted method just generates novarc out of the project zip file and sources it for you. If you use the manual method through a zip file, before sourcing novarc be sure to save any credentials that were created previously, as they can be overridden. When you run nova-api the first time, it generates the certificate authority information, including openssl.cnf. If the CA components are started prior to this, you may not be able to create your zip file. Restart the services, then once your CA information is available, you should be able to create your zip file. You may also need to check your http proxy settings to see if they are causing problems with the novarc creation.

Sometimes a particular instance shows "pending" or you cannot SSH to it. Sometimes the image itself is the problem. For example, when using flat manager networking, you do not have a dhcp server, and certain images don't support interface injection so you cannot connect to them. The fix for this type of problem is to use an image that does support this method, such as Ubuntu, which should obtain an IP address correctly with FlatManager network settings. To troubleshoot other possible problems with an instance, such as one that stays in a spawning state, first check the directory for the particular instance under /var/lib/nova/instances on the nova-compute host and make sure it has the following files: libvirt.xml disk disk-raw kernel ramdisk console.log (Once the instance actually starts you should see a console.log.) Check the file sizes to see if they are reasonable. If any are missing/zero/very small then nova-compute has somehow not completed download of the images from the Image service. Also check nova-compute.log for exceptions. Sometimes they don't show up in the console output. Next, check the log file for the instance in the directory /var/log/libvirt/qemu to see if it exists and has any useful error messages in it. Finally, from the directory for the instance under /var/lib/nova/instances, try # virsh create libvirt.xml and see if you get an error when running this.

If an instance gets stuck in an intermediate state (e.g., "deleting"), you can manually reset the state of an instance using the nova reset-state command. This will reset it to an error state, which you can then delete. For example:$ nova reset-state c6bbbf26-b40a-47e7-8d5c-eb17bf65c485 $ nova delete c6bbbf26-b40a-47e7-8d5c-eb17bf65c485 You can also use the --active to force the instance back into an active state instead of an error state, for example:$ nova reset-state --active c6bbbf26-b40a-47e7-8d5c-eb17bf65c485

If you are diagnosing problems with instances not booting, or booting slowly, consider investigating file injection as a cause. Setting libvirt_injection_partition to -2 disables injection in libvirt. This can be required if you want to make user specified files available from the metadata server (and config drive is not enabled), for performance reasons, and also to avoid boot failure if injection itself fails.