Instance errors

Sometimes a particular instance shows pending or you cannot SSH to it. Sometimes the image itself is the problem. For example, when you use flat manager networking, you do not have a DHCP server and certain images do not support interface injection; you cannot connect to them. The fix for this problem is to use an image that does support this method, such as Ubuntu, which obtains an IP address correctly with FlatManager network settings.

To troubleshoot other possible problems with an instance, such as an instance that stays in a spawning state, check the directory for the particular instance under /var/lib/nova/instances on the nova-compute host and make sure that these files are present:

If any files are missing, empty, or very small, the nova-compute service did not successfully download the images from the Image Service.

Also check nova-compute.log for exceptions. Sometimes they do not appear in the console output.

Next, check the log file for the instance in the /var/log/libvirt/qemu directory to see if it exists and has any useful error messages in it.

Finally, from the /var/lib/nova/instances directory for the instance, see if this command returns an error:

# virsh create libvirt.xml