ironic/doc/source/deploy/troubleshooting.rst

Troubleshooting Ironic

Nova returns "No valid host was found" Error

Sometimes Nova Conductor log file "nova-conductor.log" or a message returned from Nova API contains the following error:

NoValidHost: No valid host was found. There are not enough hosts available.

"No valid host was found" means that the Nova Scheduler could not find a bare metal node suitable for booting the new instance.

This in turn usually means some mismatch between resources that Nova expects to find and resources that Ironic advertised to Nova.

A few things should be checked in this case:

1. Inspection should have succeeded for you before, or you should have entered the required Ironic node properties manually. For each node with available state in ironic node-list --provision-state available use :

   ironic node-show <IRONIC-NODE-UUID>

   and make sure that properties JSON field has valid values for keys cpus, cpu_arch, memory_mb and local_gb.

2. The Nova flavor that you are using does not match any properties of the available Ironic nodes. Use :

   nova flavor-show <FLAVOR NAME>

   to compare. If you're using exact match filters in Nova Scheduler, please make sure the flavor and the node properties match exactly. Regarding the extra specs in flavor, you should make sure they map to node.properties['capabilities'].

3. Make sure that enough nodes are in available state according to ironic node-list --provision-state available.

4. Make sure nodes you're going to deploy to are not in maintenance mode. Again, use ironic node-list to check. A node automatically going to maintenance mode usually means wrong power credentials for this node. Check them and then remove maintenance mode:

   ironic node-set-maintenance <IRONIC-NODE-UUID> off

5. After making changes to nodes in Ironic, it takes time for those changes to propagate from Ironic to Nova. Check that :

   nova hypervisor-stats

   correctly shows total amount of resources in your system. You can also check nova hypervisor-list to see the status of individual Ironic nodes as reported to Nova. And you can correlate the Nova "hypervisor hostname" to the Ironic node UUID.

6. If none of the above helped, check Ironic conductor log carefully to see if there are any conductor-related errors which are the root cause for "No valid host was found". If there are any "Error in deploy of node <IRONIC-NODE-UUID>: [Errno 28] ..." error messages in Ironic conductor log, it means the conductor run into a special error during deployment. So you can check the log carefully to fix or work around and then try again.

API Errors

The debug_tracebacks_in_api config option may be set to return tracebacks in the API response for all 4xx and 5xx errors.