diff --git a/lib/facter/current_config_hosts.rb b/lib/facter/current_config_hosts.rb
new file mode 100644
index 000000000..aee13e4b3
--- /dev/null
+++ b/lib/facter/current_config_hosts.rb
@@ -0,0 +1,64 @@
+def get_auth(component)
+  provider = Object.const_get "Puppet::Provider::#{component.capitalize}"
+  auth_func = "#{component}_credentials"
+  if provider.respond_to?(auth_func)
+    begin
+      q = provider.send(auth_func)
+    rescue Puppet::Error
+      q = {}
+    end
+    authenv = {
+      'OS_AUTH_URL'     => q['auth_url'],
+      'OS_USERNAME'     => q['username'],
+      'OS_PROJECT_NAME' => q['project_name'],
+      'OS_PASSWORD'     => q['password']
+    }
+    if q.key?('region_name')
+      authenv['OS_REGION_NAME'] = q['region_name']
+    end
+    authenv
+  end
+end
+
+def get_live_value_from_auth(component)
+  # The path is correct for this tripleo version.
+  provider_file = "/etc/puppet/modules/#{component}/lib/puppet/provider/#{component}.rb"
+  if File.exists?(provider_file)
+    require_relative(provider_file)
+    auth_env = get_auth(component)
+    host = if auth_env
+             Facter::Core::Execution.with_env(auth_env) do
+               # We want to find if the current host value is the fqdn
+               # or the hostname.  We are sure that it will be at
+               # least the hostname so the grep will work.
+               Facter::Core::Execution.execute(
+                 "#{component} agent-list -c host -f value 2>/dev/null | grep #{Facter.value(:hostname)} 2>/dev/null",
+                 {:on_fail => ''}
+               ).split("\n").first
+             end
+           end
+    host || ''
+  end
+end
+
+def get_nova_live_value
+  Tempfile.open('get-nova-host') do |nova_stdin|
+    File.open(nova_stdin, 'w') do |nova_cmd|
+      nova_cmd.puts("import nova.conf\nprint nova.conf.CONF.host")
+    end
+    Facter::Core::Execution.execute("nova-manage shell python 2>/dev/null < #{nova_stdin} | sed -e 's/^[> ]*//'")
+  end
+end
+
+['nova', 'neutron'].each do |component|
+  Facter.add("current_#{component}_host") do
+    confine kernel: 'Linux'
+    setcode do
+      if component == 'nova'
+        get_nova_live_value.strip
+      else
+        get_live_value_from_auth(component).strip
+      end
+    end
+  end
+end
diff --git a/manifests/profile/base/neutron.pp b/manifests/profile/base/neutron.pp
index 993028f8d..002f2b870 100644
--- a/manifests/profile/base/neutron.pp
+++ b/manifests/profile/base/neutron.pp
@@ -63,8 +63,25 @@ class tripleo::profile::base::neutron (
     elsif $dhcp_agent_count > 0 {
       $dhcp_agents_per_net = $dhcp_agent_count
     }
+    if hiera('stack_action', undef) == 'UPDATE' {
+      if !empty($::current_neutron_host) {
+        $host_real = $::current_neutron_host
+      }
+      # Try nova value as we could be on a compute node without all
+      # the necessary neutron definition.  The host value will be identical.
+      elsif !empty($::current_nova_host) {
+        $host_real = $::current_nova_host
+      } else {
+        # We fail instead of blindly changing that value as it can
+        # break the overcloud.
+        fail("We couldn't get the live value of the neutron agent, please contact support.")
+      }
+    } else {
+      $host_real = hiera('neutron::host')
+    }
 
     class { '::neutron' :
+      host                    => $host_real,
       rabbit_hosts            => $rabbit_endpoints,
       dhcp_agents_per_network => $dhcp_agents_per_net,
     }
diff --git a/manifests/profile/base/nova.pp b/manifests/profile/base/nova.pp
index 84ba604fc..37eed298e 100644
--- a/manifests/profile/base/nova.pp
+++ b/manifests/profile/base/nova.pp
@@ -89,8 +89,23 @@ class tripleo::profile::base::nova (
   $migration_ssh_localaddrs_real = unique($migration_ssh_localaddrs)
 
   if $step >= 4 or ($step >= 3 and $sync_db) {
+
+    if hiera('stack_action', undef) == 'UPDATE' {
+      if empty($::current_nova_host) {
+        # We fail instead of blindly changing that value as it can
+        # break the overcloud.
+        fail("We couldn't get the live value of the nova agent, please contact support.")
+      } else {
+        $host_real = $::current_nova_host
+      }
+    }    else {
+      $host_real = hiera('nova::host')
+    }
+
+
     $rabbit_endpoints = suffix(any2array(normalize_ip_for_uri($rabbit_hosts)), ":${rabbit_port}")
     class { '::nova' :
+      host         => $host_real,
       rabbit_hosts => $rabbit_endpoints,
     }
     include ::nova::config
diff --git a/spec/classes/tripleo_profile_base_neutron_spec.rb b/spec/classes/tripleo_profile_base_neutron_spec.rb
new file mode 100644
index 000000000..dbdb80853
--- /dev/null
+++ b/spec/classes/tripleo_profile_base_neutron_spec.rb
@@ -0,0 +1,78 @@
+#
+# Copyright (C) 2017 Red Hat, Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+#
+
+require 'spec_helper'
+
+describe 'tripleo::profile::base::neutron' do
+  let :params do
+    { :step => 5}
+  end
+
+  shared_examples_for 'tripleo::profile::base::neutron' do
+    before :each do
+      facts.merge!({ :step => params[:step] })
+    end
+
+    context "during deployment" do
+      let(:facts) { super().merge({:current_neutron_host => ''})}
+      it 'should set neutron::host to fqdn_canonical' do
+        is_expected.to contain_class('neutron').with(:host => 'node.example.com')
+      end
+    end
+
+    context 'during upgrade' do
+      let(:facts) { super().merge({:heat_stack_action => '_update'})}
+      context 'when current host is different from fqdn' do
+        let(:facts) { super().merge({:current_neutron_host => 'node'})}
+        it "should use the current_host" do
+          is_expected.to contain_class('neutron').with(
+                           :host => 'node',
+                         )
+        end
+      end
+      context 'when current neutron host cannot be found but nova host can' do
+        let(:facts) { super().merge({:current_neutron_host => '',
+                                     :current_nova_host    => 'node'})}
+        it "should use the current_nova_host" do
+          is_expected.to contain_class('neutron').with(
+                           :host => 'node',
+                         )
+        end
+      end
+      context 'when both nova and neutron current host cannot be found' do
+        let(:facts) { super().merge({:current_neutron_host => '',
+                                     :current_nova_host    => '',
+                                    })}
+        it "fails" do
+          is_expected.to compile.and_raise_error(/live value of the neutron/)
+        end
+      end
+    end
+  end
+
+  on_supported_os.each do |os, facts|
+    context "on #{os}" do
+      let(:facts) do
+        facts.merge({
+                      :hostname             => 'node.example.com',
+                      :current_neutron_host => 'node.example.com'
+                    })
+      end
+
+      it_behaves_like 'tripleo::profile::base::neutron'
+    end
+  end
+end
diff --git a/spec/classes/tripleo_profile_base_nova_spec.rb b/spec/classes/tripleo_profile_base_nova_spec.rb
index 15b82eb48..581c8abf6 100644
--- a/spec/classes/tripleo_profile_base_nova_spec.rb
+++ b/spec/classes/tripleo_profile_base_nova_spec.rb
@@ -43,6 +43,7 @@ describe 'tripleo::profile::base::nova' do
       it {
         is_expected.to contain_class('tripleo::profile::base::nova')
         is_expected.to contain_class('nova').with(
+          :host         => 'node.example.com',
           :rabbit_hosts => ['127.0.0.1:5672']
 
         )
@@ -496,13 +497,35 @@ describe 'tripleo::profile::base::nova' do
       }
     end
 
+    context 'during upgrade' do
+      let(:params) { {
+        :step => 4,
+      } }
+      let(:facts) { super().merge({:heat_stack_action => '_update'})}
+
+      context 'when current nova host is different from fqdn' do
+        let(:facts) { super().merge({:current_nova_host => 'node'})}
+        it "should use the current_host" do
+          is_expected.to contain_class('nova').with(
+                           :host => 'node',
+                         )
+        end
+      end
+      context 'when current nova host cannot be found' do
+        let(:facts) { super().merge({:current_nova_host => ''})}
+        it "fails" do
+          is_expected.to compile.and_raise_error(/live value of the nova/)
+        end
+      end
+    end
+
   end
 
 
   on_supported_os.each do |os, facts|
     context "on #{os}" do
       let(:facts) do
-        facts.merge({ :hostname => 'node.example.com' })
+        facts.merge({:hostname => 'node.example.com'})
       end
 
       it_behaves_like 'tripleo::profile::base::nova'
diff --git a/spec/fixtures/hiera.yaml b/spec/fixtures/hiera.yaml
index 1dc3360cb..5c0c40ed3 100644
--- a/spec/fixtures/hiera.yaml
+++ b/spec/fixtures/hiera.yaml
@@ -5,3 +5,4 @@
   :datadir: './spec/fixtures/hieradata'
 :hierarchy:
   - default
+  - 'host_param%{::heat_stack_action}'
diff --git a/spec/fixtures/hieradata/host_param.yaml b/spec/fixtures/hieradata/host_param.yaml
new file mode 100644
index 000000000..cd0b00afc
--- /dev/null
+++ b/spec/fixtures/hieradata/host_param.yaml
@@ -0,0 +1,3 @@
+---
+neutron::host: 'node.example.com'
+nova::host: 'node.example.com'
diff --git a/spec/fixtures/hieradata/host_param_update.yaml b/spec/fixtures/hieradata/host_param_update.yaml
new file mode 100644
index 000000000..ba1fa4b23
--- /dev/null
+++ b/spec/fixtures/hieradata/host_param_update.yaml
@@ -0,0 +1,4 @@
+---
+stack_action: 'UPDATE'
+neutron::host: 'node.example.com'
+nova::host: 'node.example.com'