Merge pull request #606 from shawnlower/shawnlower_add-guest-agent-support

Add support for libvirt channels:

README.md

@@ -222,7 +222,7 @@ end
 * `tpm_path` - The path to the TPM device on the host system.
 * `dtb` - The device tree blob file, mostly used for non-x86 platforms. In case the device tree isn't added in-line to the kernel, it can be manually specified here.
 * `autostart` - Automatically start the domain when the host boots. Defaults to 'false'.
-
+* `channel` - [libvirt channels](https://libvirt.org/formatdomain.html#elementCharChannel). Configure a private communication channel between the host and guest, e.g. for use by the [qemu guest agent](http://wiki.libvirt.org/page/Qemu_guest_agent) and the Spice/QXL graphics type.
 
 Specific domain settings can be set for each domain separately in multi-VM
 environment. Example below shows a part of Vagrantfile, where specific options
@@ -715,6 +715,68 @@ Vagrant.configure("2") do |config|
 end
 ```
 
+## Libvirt communication channels
+
+For certain functionality to be available within a guest, a private
+communication channel must be established with the host. Two notable examples of
+this are the qemu guest agent, and the Spice/QXL graphics type.
+
+Below is a simple example which exposes a virtio serial channel to the guest. Note: in a multi-VM environment, the channel would be created for all VMs.
+
+```ruby
+vagrant.configure(2) do |config|
+  config.vm.provider :libvirt do |libvirt|
+    libvirt.channel :type => 'unix', :target_name => 'org.qemu.guest_agent.0', :target_type => 'virtio'
+  end
+end
+```
+
+Below is the syntax for creating a spicevmc channel for use by a qxl graphics card.
+
+```ruby
+vagrant.configure(2) do |config|
+  config.vm.provider :libvirt do |libvirt|
+	libvirt.channel :type => 'spicevmc', :target_name => 'com.redhat.spice.0', :target_type => 'virtio'
+  end
+end
+```
+
+These settings can be specified on a per-VM basis, however the per-guest settings will OVERRIDE any global 'config' setting. In the following example, we create 3 VM with the following configuration:
+
+master: No channel settings specified, so we default to the provider setting of a single virtio guest agent channel.
+node1: Override the channel setting, setting both the guest agent channel, and a spicevmc channel
+node2: Override the channel setting, setting both the guest agent channel, and a 'guestfwd' channel. TCP traffic sent by the guest to the given IP address and port is forwarded to the host socket /tmp/foo. Note: this device must be unique for each VM.
+
+Example
+
+```ruby
+Vagrant.configure(2) do |config|
+  config.vm.box = "fedora/23-cloud-base"
+  config.vm.provider :libvirt do |libvirt|
+    libvirt.channel :type => 'unix', :target_name => 'org.qemu.guest_agent.0', :target_type => 'virtio'
+  end 
+
+  config.vm.define "master" do |master|
+    master.vm.provider :libvirt do |domain|
+        domain.memory = 1024
+    end 
+  end 
+  config.vm.define "node1" do |node1|
+    node1.vm.provider :libvirt do |domain|
+      domain.channel :type => 'unix', :target_name => 'org.qemu.guest_agent.0', :target_type => 'virtio'
+      domain.channel :type => 'spicevmc', :target_name => 'com.redhat.spice.0', :target_type => 'virtio'
+    end 
+  end 
+  config.vm.define "node2" do |node2|
+    node2.vm.provider :libvirt do |domain|
+      domain.channel :type => 'unix', :target_name => 'org.qemu.guest_agent.0', :target_type => 'virtio'
+      domain.channel :type => 'unix', :target_type => 'guestfwd', :target_address => '192.0.2.42', :target_port => '4242',
+                     :source_path => '/tmp/foo'
+    end 
+  end 
+end
+```
+
 ## Box Format
 
 You can view an example box in the [example_box/directory](https://github.com/vagrant-libvirt/vagrant-libvirt/tree/master/example_box). That directory also contains instructions on how to build a box.

lib/vagrant-libvirt/action/create_domain.rb

@@ -79,6 +79,9 @@ module VagrantPlugins
           # Input
           @inputs = config.inputs
 
+          # Channels
+          @channels = config.channels
+
           # PCI device passthrough
           @pcis = config.pcis
 
@@ -205,6 +208,11 @@ module VagrantPlugins
             env[:ui].info(" -- INPUT:             type=#{input[:type]}, bus=#{input[:bus]}")
           end
 
+          @channels.each do |channel|
+            env[:ui].info(" -- CHANNEL:             type=#{channel[:type]}, mode=#{channel[:source_mode]}")
+            env[:ui].info(" -- CHANNEL:             target_type=#{channel[:target_type]}, target_name=#{channel[:target_name]}")
+          end
+
           @pcis.each do |pci|
             env[:ui].info(" -- PCI passthrough:   #{pci[:bus]}:#{pci[:slot]}.#{pci[:function]}")
           end

lib/vagrant-libvirt/config.rb

@@ -56,6 +56,7 @@ module VagrantPlugins
       # Domain specific settings used while creating new domain.
       attr_accessor :uuid
       attr_accessor :memory
+      attr_accessor :channel
       attr_accessor :cpus
       attr_accessor :cpu_mode
       attr_accessor :cpu_model
@@ -103,6 +104,9 @@ module VagrantPlugins
       # Inputs
       attr_accessor :inputs
 
+      # Channels
+      attr_accessor :channels
+
       # PCI device passthrough
       attr_accessor :pcis
 
@@ -177,6 +181,9 @@ module VagrantPlugins
         # Inputs
         @inputs            = UNSET_VALUE
 
+        # Channels
+        @channels          = UNSET_VALUE
+
         # PCI device passthrough
         @pcis              = UNSET_VALUE
 
@@ -255,6 +262,32 @@ module VagrantPlugins
         })
       end
 
+      def channel(options={})
+        if options[:type].nil?
+            raise "Channel type must be specified."
+        elsif options[:type] == 'unix' && options[:target_type] == 'guestfwd'
+            # Guest forwarding requires a target (ip address) and a port
+            if options[:target_address].nil? || options[:target_port].nil? ||
+               options[:source_path].nil?
+              raise 'guestfwd requires target_address, target_port and source_path'
+            end
+        end
+
+        if @channels == UNSET_VALUE
+          @channels = []
+        end
+
+        @channels.push({
+          type: options[:type],
+          source_mode: options[:source_mode],
+          source_path: options[:source_path],
+          target_address: options[:target_address],
+          target_name: options[:target_name],
+          target_port: options[:target_port],
+          target_type: options[:target_type]
+        })
+      end
+
       def pci(options={})
         if options[:bus].nil? || options[:slot].nil? || options[:function].nil?
           raise 'Bus AND slot AND function must be specified. Check `lspci` for that numbers.'
@@ -465,6 +498,9 @@ module VagrantPlugins
         # Inputs
         @inputs = [{:type => "mouse", :bus => "ps2"}] if @inputs == UNSET_VALUE
 
+        # Channels
+        @channels = [ ] if @channels == UNSET_VALUE
+
         # PCI device passthrough
         @pcis = [] if @pcis == UNSET_VALUE
 

lib/vagrant-libvirt/templates/domain.xml.erb

@@ -96,6 +96,27 @@
       <target port='0'/>
     </console>
 
+<% @channels.each do |channel| %>
+  <channel type='<%= channel[:type] %>' >
+      <source mode='<%= channel[:source_mode] %>'
+          <% if channel[:source_path] %>
+               path="<%= channel[:source_path] %>"
+          <% end %>
+      />
+      <target type='<%= channel[:target_type] %>'
+          <% if channel[:target_name] %>
+               name="<%= channel[:target_name] %>"
+          <% end %>
+          <% if channel[:target_address] %>
+               address="<%= channel[:target_address] %>"
+          <% end %>
+          <% if channel[:target_port] %>
+               port="<%= channel[:target_port] %>"
+          <% end %>
+      />
+  </channel>
+<% end %>
+
 <% @inputs.each do |input| %>
     <input type='<%= input[:type] %>' bus='<%= input[:bus] %>'/>
 <% end %>