Oh it looks like this error triggers always, even if you select an image. Testing with OS.

Looks like the image gets stored properly (image_ref) but the ssh_provision orchestrator is returned nil:

2016-01-11T11:51:14 [app] [I]   Parameters: {"utf8"=>"✓", "authenticity_token"=>"xxxx+BtOzpO938g=", "host"=>{"name"=>"lzap-test-04", "organization_id"=>"3", "location_id"=>"1", "hostgroup_id"=>"7", "compute_resource_id"=>"5", "puppetclass_ids"=>[""], "managed"=>"true", "progress_report_id"=>"[FILTERED]", "type"=>"Host::Managed", "interfaces_attributes"=>{"0"=>{"_destroy"=>"0", "type"=>"Nic::Managed", "mac"=>"", "identifier"=>"", "name"=>"lzap-test-04", "domain_id"=>"1", "subnet_id"=>"1", "ip"=>"192.168.122.20", "managed"=>"1", "primary"=>"1", "provision"=>"1", "virtual"=>"0", "tag"=>"", "attached_to"=>""}}, "compute_attributes"=>{"flavor_ref"=>"83098b08-7339-4089-bc07-3f2a14b7a4c1", "availability_zone"=>"", "tenant_id"=>"2f58867f4fa54a09a266b26ef410d313", "security_groups"=>"lzap-group", "nics"=>[""], "network"=>"os1_internal", "boot_from_volume"=>"false", "size_gb"=>"", "image_ref"=>"2695dbd9-e1b1-47a8-9ac3-4e8854aa55aa"}, "architecture_id"=>"1", "operatingsystem_id"=>"5", "provision_method"=>"image", "build"=>"1", "disk"=>"", "root_pass"=>"[FILTERED]", "is_owned_by"=>"1-Users", "enabled"=>"1", "model_id"=>"", "comment"=>"", "overwrite"=>"false"}, "capabilities"=>"image", "provider"=>"Openstack", "bare_metal_capabilities"=>"build"}

Host -> Image reference does not get updated properly.

It looks like again, hash with symbol vs string in my case:

[8] pry(#<Host::Managed>)> compute_attributes
=> {"flavor_ref"=>"83098b08-7339-4089-bc07-3f2a14b7a4c1",
 "availability_zone"=>"",
 "tenant_id"=>"2f58867f4fa54a09a266b26ef410d313",
 "security_groups"=>"lzap-group",
 "nics"=>[""],
 "network"=>"os1_internal",
 "boot_from_volume"=>"false",
 "size_gb"=>"",
 "image_ref"=>"2695dbd9-e1b1-47a8-9ac3-4e8854aa55aa",
 "interfaces_attributes"=>{"0"=>{}}}
[9] pry(#<Host::Managed>)> compute_attributes[:image_ref]
=> nil