Implement support for passing scheduler hints

Signed-off-by: Igor Raits <i.gnatenko.brain@gmail.com>

README.md

@@ -204,6 +204,20 @@ If your vms require config drive.
     config_drive: true
 ```
 
+### scheduler\_hints
+
+If you wish to pass any scheduler hints.
+
+```
+    scheduler_hints:
+      group: b0f6f534-3a02-4dfa-9165-605446799cc0
+      query: >-
+        ["or",
+	  ["=", "$host", "cmp123.example.com"],
+	  ["=", "$host", "cmp456.example.com"]
+	]
+```
+
 ### network\_ref
 
 **Deprecated** A list of network names to create instances with.

lib/kitchen/driver/openstack.rb

@@ -200,6 +200,10 @@ def create_server
           server_def[c] = optional_config(c) if config[c]
         end
 
+        if config[:scheduler_hints]
+          server_def["os:scheduler_hints"] = optional_config(:scheduler_hints)
+        end
+
         # Can't use the Fog bootstrap and/or setup methods here; they require a
         # public IP address that can't be guaranteed to exist across all
         # OpenStack deployments (e.g. TryStack ARM only has private IPs).
@@ -224,6 +228,8 @@ def optional_config(c)
           config[c] if config[c].is_a?(Array)
         when :user_data
           File.open(config[c], &:read) if File.exist?(config[c])
+        when :scheduler_hints
+          config[c] if config[c].is_a?(Hash)
         else
           config[c]
         end

spec/kitchen/driver/openstack_spec.rb

@@ -534,6 +534,35 @@
       end
     end
 
+    context "scheduler_hints specified" do
+      let(:config) do
+        {
+          server_name: "hello",
+          image_ref: "111",
+          flavor_ref: "1",
+          scheduler_hints: {
+            group: "3df3519e-0e22-4d14-8c6a-afd8e4467b4b",
+          },
+        }
+      end
+      let(:data) do
+        {
+          group: "3df3519e-0e22-4d14-8c6a-afd8e4467b4b",
+        }
+      end
+
+      it "passes scheduler_hints contents" do
+        expect(servers).to receive(:create).with(
+          name: "hello",
+          image_ref: "111",
+          flavor_ref: "1",
+          availability_zone: nil,
+          "os:scheduler_hints" => data
+        )
+        driver.send(:create_server)
+      end
+    end
+
     context "image_id specified" do
       let(:config) do
         {