Merge pull request #711 from tas50/ec2_detection

Improve EC2 detection when hint isn't present

2 files changed, 36 insertions, 2 deletions

diff --git a/lib/ohai/plugins/ec2.rb b/lib/ohai/plugins/ec2.rb
index c6355dbc..7ad80e5e 100644
--- a/lib/ohai/plugins/ec2.rb
+++ b/lib/ohai/plugins/ec2.rb
@@ -26,7 +26,9 @@ Ohai.plugin(:EC2) do
   provides "ec2"
 
   depends "network/interfaces"
+  depends "dmi"
 
+  # look for arp address that non-VPC hosts will have
   def has_ec2_mac?
     network[:interfaces].values.each do |iface|
       unless iface[:arp].nil?
@@ -40,10 +42,26 @@ Ohai.plugin(:EC2) do
     false
   end
 
+  # look for amazon string in dmi bios data
+  # this only works on hvm instances as paravirt instances have no dmi data
+  def has_ec2_dmi?
+    begin
+      # detect a version of '4.2.amazon'
+      if dmi[:bios][:all_records][0][:Version] =~ /amazon/
+        Ohai::Log.debug("has_ec2_dmi? == true")
+        true
+      end
+    rescue NoMethodError
+      Ohai::Log.debug("has_ec2_dmi? == false")
+      false
+    end
+  end
+
+
   def looks_like_ec2?
     # Try non-blocking connect so we don't "block" if
     # the Xen environment is *not* EC2
-    hint?('ec2') || has_ec2_mac? && can_metadata_connect?(Ohai::Mixin::Ec2Metadata::EC2_METADATA_ADDR,80)
+    hint?('ec2') || ( has_ec2_dmi? || has_ec2_mac?) && can_metadata_connect?(Ohai::Mixin::Ec2Metadata::EC2_METADATA_ADDR,80)
   end
 
   collect_data do
@@ -60,7 +78,7 @@ Ohai.plugin(:EC2) do
       end
       ec2[:userdata] = self.fetch_userdata
       #ASCII-8BIT is equivalent to BINARY in this case
-      if ec2[:userdata].encoding.to_s == "ASCII-8BIT"
+      if ec2[:userdata] && ec2[:userdata].encoding.to_s == "ASCII-8BIT"
         Ohai::Log.debug("Binary UserData Found. Storing in base64")
         ec2[:userdata] = Base64.encode64(ec2[:userdata])
       end
diff --git a/spec/unit/plugins/ec2_spec.rb b/spec/unit/plugins/ec2_spec.rb
index 86b53d2c..0b02df1c 100644
--- a/spec/unit/plugins/ec2_spec.rb
+++ b/spec/unit/plugins/ec2_spec.rb
@@ -270,6 +270,22 @@ end
     end
   end
 
+  describe "with ec2 dmi data" do
+    it_should_behave_like "ec2"
+
+    before(:each) do
+      @plugin[:dmi] = { :bios => { :all_records => [  { :Version => "4.2.amazon" } ] } }
+    end
+  end
+
+  describe "without ec2 dmi data" do
+    it_should_behave_like "!ec2"
+
+    before(:each) do
+      @plugin[:dmi] = nil
+    end
+  end
+
   describe "with ec2 cloud file" do
     it_should_behave_like "ec2"