Detect docker hosts in the Virtualization plugin

Useful information to have and lets us write a docker plugin to collect more information.

Signed-off-by: Tim Smith <tsmith@chef.io>

2 files changed, 27 insertions, 8 deletions

diff --git a/lib/ohai/plugins/darwin/virtualization.rb b/lib/ohai/plugins/darwin/virtualization.rb
index 61102cf1..318886a6 100644
--- a/lib/ohai/plugins/darwin/virtualization.rb
+++ b/lib/ohai/plugins/darwin/virtualization.rb
@@ -37,10 +37,20 @@ Ohai.plugin(:Virtualization) do
     ::File.exist?("/Applications/VMware\ Fusion.app/")
   end
 
+  def docker_exists?
+    which("docker")
+  end
+
   collect_data(:darwin) do
     virtualization Mash.new unless virtualization
     virtualization[:systems] = Mash.new unless virtualization[:systems]
 
+    if docker_exists?
+      virtualization[:system] = "docker"
+      virtualization[:role] = "host"
+      virtualization[:systems][:docker] = "host"
+    end
+
     if vboxmanage_exists?
       virtualization[:system] = "vbox"
       virtualization[:role] = "host"
diff --git a/lib/ohai/plugins/linux/virtualization.rb b/lib/ohai/plugins/linux/virtualization.rb
index 797ea4e5..1b492207 100644
--- a/lib/ohai/plugins/linux/virtualization.rb
+++ b/lib/ohai/plugins/linux/virtualization.rb
@@ -29,12 +29,27 @@ Ohai.plugin(:Virtualization) do
     which("nova")
   end
 
+  def docker_exists?
+    which("docker")
+  end
+
   collect_data(:linux) do
     virtualization Mash.new unless virtualization
     virtualization[:systems] = Mash.new unless virtualization[:systems]
 
-    ## Xen
-    # /proc/xen is an empty dir for EL6 + Linode Guests + Paravirt EC2 instances
+    # Docker hosts
+    if docker_exists?
+      virtualization[:system] = "docker"
+      virtualization[:role] = "host"
+      virtualization[:systems][:docker] = "host"
+    end
+
+    # Xen Notes:
+    # - /proc/xen is an empty dir for EL6 + Linode Guests + Paravirt EC2 instances
+    # - cpuid of guests, if we could get it, would also be a clue
+    # - may be able to determine if under paravirt from /dev/xen/evtchn (See OHAI-253)
+    # - Additional edge cases likely should not change the above assumptions
+    #   but rather be additive - btm
     if File.exist?("/proc/xen")
       virtualization[:system] = "xen"
       # Assume guest
@@ -51,12 +66,6 @@ Ohai.plugin(:Virtualization) do
       end
     end
 
-    # Xen Notes:
-    # - cpuid of guests, if we could get it, would also be a clue
-    # - may be able to determine if under paravirt from /dev/xen/evtchn (See OHAI-253)
-    # - Additional edge cases likely should not change the above assumptions
-    #   but rather be additive - btm
-
     # Detect Virtualbox from kernel module
     if File.exist?("/proc/modules")
       modules = File.read("/proc/modules")