Improve detection of Windows EC2 nodes by using UUID information

lib/ohai/plugins/ec2.rb

@@ -24,21 +24,20 @@
 # 3. DMI data mentions amazon. This catches HVM instances in a VPC
 # 4. Kernel data mentioned Amazon. This catches Windows HVM & paravirt instances
 
-require "ohai/mixin/ec2_metadata"
-require "ohai/mixin/http_helper"
-require "base64"
-
 Ohai.plugin(:EC2) do
+  require "ohai/mixin/ec2_metadata"
+  require "ohai/mixin/http_helper"
+  require "base64"
+
   include Ohai::Mixin::Ec2Metadata
   include Ohai::Mixin::HttpHelper
 
   provides "ec2"
-
   depends "dmi"
-  depends "kernel"
 
   # look for amazon string in dmi bios data
   # this gets us detection of HVM instances that are within a VPC
+  # @return [Boolean] do we have Amazon DMI data?
   def has_ec2_dmi?
     # detect a version of '4.2.amazon'
     if get_attribute(:dmi, :bios, :all_records, 0, :Version) =~ /amazon/
@@ -51,7 +50,9 @@ def has_ec2_dmi?
   end
 
   # looks for a xen UUID that starts with ec2
-  # this gets us detection of Linux HVM and Paravirt hosts
+  # uses the sys tree on Linux and a WMI query on windows
+  # this gets us detection of HVM and Paravirt hosts
+  # @return [Boolean] do we have a Xen UUID or not?
   def has_ec2_xen_uuid?
     if ::File.exist?("/sys/hypervisor/uuid")
       if ::File.read("/sys/hypervisor/uuid") =~ /^ec2/
@@ -63,24 +64,31 @@ def has_ec2_xen_uuid?
     false
   end
 
-  # looks for the Amazon.com Organization in Windows Kernel data
-  # this gets us detection of Windows systems
-  def has_amazon_org?
-    # detect an Organization of 'Amazon.com'
-    if get_attribute(:kernel, :os_info, :organization) =~ /Amazon/
-      Ohai::Log.debug("Plugin EC2: has_amazon_org? == true")
-      true
+  # looks at the identifying number WMI value to see if it starts with ec2.
+  # this is actually the same value we're looking at in has_ec2_xen_uuid? on
+  # linux hosts
+  # @return [Boolean] do we have a Xen Identifying Number or not?
+  def has_ec2_identifying_number?
+    if RUBY_PLATFORM =~ /mswin|mingw32|windows/
+    #  require "wmi-lite/wmi"
+      wmi = WmiLite::Wmi.new
+      if wmi.first_of("Win32_ComputerSystemProduct")["identifyingnumber"] =~ /^ec2/
+        Ohai::Log.debug("Plugin EC2: has_ec2_identifying_number? == true")
+        return true
+      end
     else
-      Ohai::Log.debug("Plugin EC2: has_amazon_org? == false")
+      Ohai::Log.debug("Plugin EC2: has_ec2_identifying_number? == false")
       false
     end
   end
 
+  # a single check that combines all the various detection methods for EC2
+  # @return [Boolean] Does the system appear to be on EC2
   def looks_like_ec2?
     return true if hint?("ec2")
 
     # Even if it looks like EC2 try to connect first
-    if has_ec2_xen_uuid? || has_ec2_dmi? || has_amazon_org?
+    if has_ec2_xen_uuid? || has_ec2_dmi? || has_ec2_identifying_number?
       return true if can_socket_connect?(Ohai::Mixin::Ec2Metadata::EC2_METADATA_ADDR, 80)
     end
   end

spec/unit/plugins/ec2_spec.rb

@@ -342,14 +342,6 @@
     end
   end
 
-  describe "with amazon kernel data" do
-    it_behaves_like "ec2"
-
-    before(:each) do
-      plugin[:kernel] = { :os_info => { :organization => "Amazon.com" } }
-    end
-  end
-
   describe "with EC2 Xen UUID" do
     it_behaves_like "ec2"
 
@@ -368,6 +360,38 @@
     end
   end
 
+  describe "with EC2 Identifying Number", :windows_only do
+    it_behaves_like "ec2"
+
+    before do
+      allow_any_instance_of(WmiLite::Wmi).to receive(:first_of).and_return(
+        { "caption" => "Computer System Product",
+          "description" => "Computer System Product",
+          "identifyingnumber" => "ec2a355a-91cd-5fe8-bbfc-cc891d0bf9d6",
+          "name" => "HVM domU",
+          "skunumber" => nil,
+          "uuid" => "5A352AEC-CD91-E85F-BBFC-CC891D0BF9D6",
+          "vendor" => "Xen",
+          "version" => "4.2.amazon" })
+    end
+  end
+
+  describe "without EC2 Identifying Number", :windows_only do
+    it_behaves_like "!ec2"
+
+    before do
+      allow_any_instance_of(WmiLite::Wmi).to receive(:first_of).and_return(
+        { "caption" => "Computer System Product",
+          "description" => "Computer System Product",
+          "identifyingnumber" => "1234",
+          "name" => "HVM domU",
+          "skunumber" => nil,
+          "uuid" => "5A352AEC-CD91-E85F-BBFC-CC891D0BF9D6",
+          "vendor" => "Xen",
+          "version" => "1.2.3" })
+    end
+  end
+
   describe "with ec2 hint file" do
     it_behaves_like "ec2"