Merge pull request #1343 from abbbi/1341_poc

Retrieve IP Address of management interface using qemu-guest-agent commands #1341

README.md

@@ -933,6 +933,23 @@ DHCP server. dnsmasq writes lease information in the `/var/lib/libvirt/dnsmasq`
 directory. Vagrant-libvirt looks for the MAC address in this file and extracts
 the corresponding IP address.
 
+It is also possible to use the Qemu Agent to extract the management interface
+configuration from the booted virtual machine. This is helpful in libvirt
+environments where no local dnsmasq is used for automatic address assigment,
+but external dhcp services via bridged libvirt networks.
+
+Prerequisite is to enable the qemu agent channel via ([Libvirt communication
+channels](#libvirt-communication-channels)) and the virtual machine image must
+have the agent pre-installed before deploy. The agent will start automatically
+if it detects an attached channel during boot.
+
+* `qemu_use_agent` - false by default, if set to true, attempt to extract configured
+  ip address via qemu agent.
+
+To use the management network interface with an external dhcp service you need
+to setup a bridged host network manually and define it via
+`management_network_name` in your Vagrantfile.
+
 ## Additional Disks
 
 You can create and attach additional disks to a VM via `libvirt.storage :file`.

lib/vagrant-libvirt/action/create_networks.rb

@@ -162,7 +162,7 @@ module VagrantPlugins
             if @interface_network[:created]
               # Just check for mismatch error here - if name and ip from
               # config match together.
-              if @options[:network_name] != @interface_network[:name]
+              if @options[:network_name] != @interface_network[:name] and @qemu_use_agent = false
                 raise Errors::NetworkNameAndAddressMismatch,
                       ip_address:   @options[:ip],
                       network_name: @options[:network_name]

lib/vagrant-libvirt/config.rb

@@ -193,6 +193,9 @@ module VagrantPlugins
       # Use QEMU session instead of system
       attr_accessor :qemu_use_session
 
+      # Use QEMU Agent to get ip address
+      attr_accessor :qemu_use_agent
+
       def initialize
         @uri               = UNSET_VALUE
         @driver            = UNSET_VALUE
@@ -332,6 +335,9 @@ module VagrantPlugins
         @qemu_env          = UNSET_VALUE
 
         @qemu_use_session  = UNSET_VALUE
+
+        # Use Qemu agent to get ip address
+        @qemu_use_agent  = UNSET_VALUE
       end
 
       def boot(device)
@@ -936,6 +942,8 @@ module VagrantPlugins
 
         # Additional QEMU commandline environment variables
         @qemu_env = {} if @qemu_env == UNSET_VALUE
+
+        @qemu_use_agent = true if @qemu_use_agent != UNSET_VALUE
       end
 
       def validate(machine)
@@ -949,6 +957,17 @@ module VagrantPlugins
           end
         end
 
+
+        if @qemu_use_agent == true
+          # if qemu agent is used to optain domain ip configuration, at least
+          # one qemu channel has to be configured. As there are various options,
+          # error out and leave configuration to the user
+          unless machine.provider_config.channels.any? { |channel| channel[:target_name].start_with?("org.qemu.guest_agent") }
+            errors << "qemu agent option enabled, but no qemu agent channel configured: please add at least one qemu agent channel to vagrant config"
+          end
+        end
+
+
         machine.provider_config.disks.each do |disk|
           if disk[:path] && (disk[:path][0] == '/')
             errors << "absolute volume paths like '#{disk[:path]}' not yet supported"

lib/vagrant-libvirt/driver.rb

@@ -3,6 +3,7 @@
 require 'fog/libvirt'
 require 'libvirt'
 require 'log4r'
+require 'json'
 
 module VagrantPlugins
   module ProviderLibvirt
@@ -58,7 +59,7 @@ module VagrantPlugins
 
         config = @machine.provider_config
 
-        @@system_connection = Libvirt::open_read_only(config.system_uri)
+        @@system_connection = Libvirt::open(config.system_uri)
         @@system_connection
       end
 
@@ -99,6 +100,12 @@ module VagrantPlugins
           return get_ipaddress_from_system domain.mac
         end
 
+        # attempt to get ip address from qemu agent
+        if @machine.provider_config.qemu_use_agent == true
+          @logger.info('Get IP via qemu agent')
+          return get_ipaddress_from_qemu_agent(domain, machine.id)
+        end
+
         # Get IP address from dhcp leases table
         begin
           ip_address = get_ipaddress_from_domain(domain)
@@ -146,6 +153,40 @@ module VagrantPlugins
         ip_address
       end
 
+      def get_ipaddress_from_qemu_agent(domain, machine_id)
+        ip_address = nil
+        addresses = nil
+        dom = system_connection.lookup_domain_by_uuid(machine_id)
+        begin
+          response = dom.qemu_agent_command('{"execute":"guest-network-get-interfaces"}', timeout=10)
+          @logger.debug("Got Response from qemu agent")
+          @logger.debug(response)
+          addresses = JSON.parse(response)
+        rescue => e
+          @logger.debug("Unable to receive IP via qemu agent: [%s]" % e.message)
+        end
+
+        unless addresses.nil?
+          addresses["return"].each{ |interface|
+            if domain.mac == interface["hardware-address"]
+              @logger.debug("Found mathing interface: [%s]" % interface["name"])
+              if interface.has_key?("ip-addresses")
+                interface["ip-addresses"].each{ |ip|
+                  # returning ipv6 addresses might break windows guests because
+                  # winrm cant handle connection, winrm fails with "invalid uri"
+                  if ip["ip-address-type"] == "ipv4"
+                    ip_address = ip["ip-address"]
+                    @logger.debug("Return IP: [%s]" % ip_address)
+                    break
+                  end
+                  }
+              end
+            end
+          }
+        end
+        ip_address
+      end
+
       def get_ipaddress_from_domain(domain)
         ip_address = nil
         domain.wait_for(2) do

lib/vagrant-libvirt/util/network_util.rb

@@ -20,6 +20,7 @@ module VagrantPlugins
 
         def configured_networks(env, logger)
           qemu_use_session = env[:machine].provider_config.qemu_use_session
+          qemu_use_agent = env[:machine].provider_config.qemu_use_agent
           management_network_device = env[:machine].provider_config.management_network_device
           management_network_name = env[:machine].provider_config.management_network_name
           management_network_address = env[:machine].provider_config.management_network_address

tests/qemu_agent/Vagrantfile

@@ -0,0 +1,13 @@
+# -*- mode: ruby -*-
+# vi: set ft=ruby :
+#
+# frozen_string_literal: true
+
+Vagrant.configure("2") do |config|
+  config.vm.box = "generic/debian10"
+  config.vm.synced_folder ".", "/vagrant", disabled: true
+  config.vm.provider :libvirt do |libvirt|
+    libvirt.channel :type => 'unix', :target_name => 'org.qemu.guest_agent.0', :target_type => 'virtio'
+    libvirt.qemu_use_agent = true
+  end
+end

tests/runtests.bats

@@ -119,6 +119,17 @@ cleanup() {
   cleanup
 }
 
+@test "bring up and use qemu agent for connectivity" {
+  export VAGRANT_CWD=tests/qemu_agent
+  cleanup
+  run ${VAGRANT_CMD} up ${VAGRANT_OPT}
+  echo "${output}"
+  echo "status = ${status}"
+  [ "$status" -eq 0 ]
+  echo "${output}"
+  cleanup
+}
+
 @test "ip is reachable with private network" {
   export VAGRANT_CWD=tests/private_network
   cleanup