Issue

Reboot operation fails if force_config_drive is switched to True after an instance was initially booted without config drive in Red Hat OpenStack Platform

The option is - by default - switched off.

[root@overcloud-controller-0 ~]# grep force_config /etc/nova/nova.conf
[root@overcloud-controller-0 ~]# 

[root@overcloud-compute-0 ~]# grep force_config /etc/nova/nova.conf
[root@overcloud-compute-0 ~]# 

If the option is explicitly configured in the templates, then instances which were booted prior to setting this option cannot be rebooted:

templates/network-environment.yaml-  NovaComputeExtraConfig:
templates/network-environment.yaml:    nova::compute::force_config_drive: true

From the upstream bug report https://bugs.launchpad.net/nova/+bug/1241806:

2013-10-18 15:26:42.268 ERROR nova.compute.manager [req-ae365347-f863-4bf3-9fc1-f2e13a8aeb6a 8d656ddf92e24f88a91a51a2c4dd5252 951ae3eceeff40db97fa6aca540a6738] [instance: 2e685095-9b7b-4711-aba6-2a7794fdafd5] Cannot reboot instance: [Errno 2] No such file or directory: '/var/lib/nova/instances/2e685095-9b7b-4711-aba6-2a7794fdafd5/disk.config'