# Instance Failure Nova can fail to launch instances inside a reservation that clearly still has free nodes. It fails with the error “No valid host found”. This can be caused by multiple reasons: 1. get the list of baremetal nodes in the lease. ``` chameleon lease resource list ``` 2. If a subset of these nodes are failing, then check the specific node: ``` openstack baremetal node show ``` 3. Check if its in maintenance mode 1. If yes, check the reason 4. Check to see if it still has an associated instance ID. If so, run: ``` openstack baremetal node undeploy ``` If these don't show an issue, its time to look at the logs. They can seen in `/var/log/kolla` on your admin node, or via kibana at `:5601` The credentials can be found in your site's ansible-vault If you see a conflict, reference There are also some commands to check the health of all nodes at a site: List all baremetal nodes in maintenance: ``` openstack baremetal node list --maintenance ``` Ironic thinks nodes are active, but doesn’t know about a specific instance ``` openstack baremetal node list --provision-state active --unassociated ```