Description of problem:
I was trying auto-provisioning manually. I discovered a pxe-less host with dhcp. Host was discovered successfully and then I defined a discovery-rule but accidentally I associated incorrect hostgroup to that rule which is associated to a different subnet. As soon as I selected the "auto-provision" from provision dropdown, I got notification rule is applied. And host was removed removed from discovered host page and moved to 'All host' page.

However when I checked the logs and found following error:

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2015-11-30 04:09:05 [I] Processing by DiscoveredHostsController#auto_provision as HTML
2015-11-30 04:09:05 [I]   Parameters: {"authenticity_token"=>"71UIz3gXvym7Vohl7d//nLh8Nuqs8uZ3uwyRcMSynNU=", "id"=>"mac52540098967a"}
2015-11-30 04:09:05 [I] Match found for host mac52540098967a (26) rule rule1 (1)
2015-11-30 04:09:05 [I] Create DHCP reservation for mac52540098967a.idmqe.lab.eng.bos.redhat.com-52:54:00:98:96:7a/192.168.100.23
2015-11-30 04:09:05 [I] Add DNS A record for mac52540098967a.idmqe.lab.eng.bos.redhat.com/192.168.100.23
2015-11-30 04:09:05 [I] Add DNS PTR record for 192.168.100.23/mac52540098967a.idmqe.lab.eng.bos.redhat.com
2015-11-30 04:09:05 [I] Add the TFTP configuration for mac52540098967a.idmqe.lab.eng.bos.redhat.com
2015-11-30 04:09:11 [I] Fetching required TFTP boot files for mac52540098967a.idmqe.lab.eng.bos.redhat.com
2015-11-30 04:09:11 [I] Redirected to https://cloud-qe-15.idmqe.lab.eng.bos.redhat.com/discovered_hosts
2015-11-30 04:09:11 [W] Unable to kexec mac52540098967a:
2015-11-30 04:09:11 [W] /opt/rh/ruby193/root/usr/share/gems/gems/rest-client-1.6.7/lib/restclient/abstract_response.rb:48:in `return!'
/opt/rh/ruby193/root/usr/share/gems/gems/rest-client-1.6.7/lib/restclient/request.rb:230:in `process_result'
/opt/rh/ruby193/root/usr/share/gems/gems/rbovirt-0.0.29/lib/restclient_ext/request.rb:50:in `block in transmit'
/opt/rh/ruby193/root/usr/share/ruby/net/http.rb:746:in `start'
/opt/rh/ruby193/root/usr/share/gems/gems/rbovirt-0.0.29/lib/restclient_ext/request.rb:44:in `transmit'
/opt/rh/ruby193/root/usr/share/gems/gems/rest-client-1.6.7/lib/restclient/request.rb:64:in `execute'
/opt/rh/ruby193/root/usr/share/gems/gems/rest-client-1.6.7/lib/restclient/request.rb:33:in `execute'
/opt/rh/ruby193/root/usr/share/gems/gems/rest-client-1.6.7/lib/restclient/resource.rb:76:in `put'

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Version-Release number of selected component (if applicable):


How reproducible:
always

Steps to Reproduce:
1. discover host via pxe-less
2. define a discovery rule and associated a hostgroup which has subnet associated from a different network than discovered host
3. auto-provision

Actual results:
1. Rule was applied
2. Host entry removed from discovered host page 
3. No error on webUI
4. Got a generic error from production.log:
2015-11-30 04:09:11 [W] Unable to kexec mac52540098967a:



Expected results:

1. I think at first place user should get an error on webUI as soon as discovery rule was applied.

2. host entry shouldn't be removed from discovered host page,

3. its would be nice if user gets a proper error in production.log instead of generic warning type message as below:

like: 2015-11-30 04:09:11 [W] Unable to kexec mac52540098967a:


Additional info: