add ansible.host_key_checking configuration parameter

plugins/provisioners/ansible/config.rb

@@ -12,6 +12,7 @@ module VagrantPlugins
       attr_accessor :tags
       attr_accessor :skip_tags
       attr_accessor :start_at_task
+      attr_accessor :host_key_checking
 
       # Joker attribute, used to pass unsupported arguments to ansible anyway
       attr_accessor :raw_arguments
@@ -29,6 +30,7 @@ module VagrantPlugins
         @skip_tags         = UNSET_VALUE
         @start_at_task     = UNSET_VALUE
         @raw_arguments     = UNSET_VALUE
+        @host_key_checking = "true"
       end
 
       def finalize!
@@ -44,6 +46,7 @@ module VagrantPlugins
         @skip_tags         = nil if @skip_tags == UNSET_VALUE
         @start_at_task     = nil if @start_at_task == UNSET_VALUE
         @raw_arguments     = nil if @raw_arguments == UNSET_VALUE
+        @host_key_checking = nil if @host_key_checking == UNSET_VALUE
       end
 
       def validate(machine)

plugins/provisioners/ansible/provisioner.rb

@@ -38,7 +38,7 @@ module VagrantPlugins
 
         # Write stdout and stderr data, since it's the regular Ansible output
         command << {
-          :env => { "ANSIBLE_FORCE_COLOR" => "true" },
+          :env => { "ANSIBLE_FORCE_COLOR" => "true" , "ANSIBLE_HOST_KEY_CHECKING" => "#{config.host_key_checking}" },
           :notify => [:stdout, :stderr],
           :workdir => @machine.env.root_path.to_s
         }

website/docs/source/v2/provisioning/ansible.html.md

@@ -141,3 +141,4 @@ by the sudo command.
 * `ansible.raw_arguments` is an *unsafe wildcard* string that can be used to take advantage of `ansible-playbook` arguments that are not (yet) supported by this Vagrant provisioner plugin. This can be very useful when integrating with bleeding edge Ansible versions. Following precedence rules apply:
   * Any supported options (described above) will override conflicting `raw_arguments` value (e.g. `--tags` or `--start-at-task`)
   * Vagrant default user authentication can be overridden via `raw_arguments` (with custom values for `--user` and `--private-key`)
+* `ansible.host_key_checking` can be set to `false` which will disable host key checking and prevent `"FAILED: (25, 'Inappropriate ioctl for device')"` errors from being reported during provisioner runs.  The default value is `true`, which matches the default behavior of Ansible 1.2.1 and later.