From bea1e1954ad793f528876c030bc0ffecb83b0787 Mon Sep 17 00:00:00 2001
From: Huan Xie <huan.xie@citrix.com>
Date: Tue, 19 Apr 2016 07:01:30 +0100
Subject: [PATCH] Set default value and configurable value for integration
 bridge

When using XenServer as hypervisor, install_os_domU.sh will create
integration bridge for compute node when neutron network is used.
But it should provide a way to allow moving of the VM to another
host (with a different XEN_INTEGRATION_BRIDGE) for easier install.
This patch is to provide the way to let user have the chance to
configure integration bridge themselves

Change-Id: If923a5e978e77fc091d24b6e1fe7a83a3375da09
---
 lib/nova_plugins/hypervisor-xenserver | 3 ++-
 tools/xen/README.md                   | 6 ++++++
 tools/xen/install_os_domU.sh          | 4 ++--
 3 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/lib/nova_plugins/hypervisor-xenserver b/lib/nova_plugins/hypervisor-xenserver
index 3eb9149bb4..e7f1e87b61 100644
--- a/lib/nova_plugins/hypervisor-xenserver
+++ b/lib/nova_plugins/hypervisor-xenserver
@@ -29,7 +29,8 @@ GUEST_INTERFACE_DEFAULT=eth1
 # Allow ``build_domU.sh`` to specify the flat network bridge via kernel args
 FLAT_NETWORK_BRIDGE_DEFAULT=$(sed -e 's/.* flat_network_bridge=\([[:alnum:]]*\).*$/\1/g' /proc/cmdline)
 if is_service_enabled neutron; then
-    XEN_INTEGRATION_BRIDGE=$(sed -e 's/.* xen_integration_bridge=\([[:alnum:]]*\).*$/\1/g' /proc/cmdline)
+    XEN_INTEGRATION_BRIDGE_DEFAULT=$(sed -e 's/.* xen_integration_bridge=\([[:alnum:]]*\).*$/\1/g' /proc/cmdline)
+    XEN_INTEGRATION_BRIDGE=${XEN_INTEGRATION_BRIDGE:-$XEN_INTEGRATION_BRIDGE_DEFAULT}
 fi
 
 VNCSERVER_PROXYCLIENT_ADDRESS=${VNCSERVER_PROXYCLIENT_ADDRESS=169.254.0.1}
diff --git a/tools/xen/README.md b/tools/xen/README.md
index 21090e56aa..7062ecb48c 100644
--- a/tools/xen/README.md
+++ b/tools/xen/README.md
@@ -170,3 +170,9 @@ VM as `TEMPLATE_FILENAME`:
     xe vm-import filename="$mountdir/$TEMPLATE_FILENAME"
     umount "$mountdir"
     rm -rf "$mountdir"
+
+### Migrate OpenStack DomU to another host
+
+Given you need to migrate your DomU with OpenStack installed to another host,
+you need to set `XEN_INTEGRATION_BRIDGE` in localrc if neutron network is used.
+It is the bridge for `XEN_INT_BRIDGE_OR_NET_NAME` network created in Dom0
diff --git a/tools/xen/install_os_domU.sh b/tools/xen/install_os_domU.sh
index 46ff0b6fda..8b97265e21 100755
--- a/tools/xen/install_os_domU.sh
+++ b/tools/xen/install_os_domU.sh
@@ -299,10 +299,10 @@ $THIS_DIR/build_xva.sh "$GUEST_NAME"
 # kernel parameter for DomU
 attach_network "$XEN_INT_BRIDGE_OR_NET_NAME"
 
-XEN_INTEGRATION_BRIDGE=$(bridge_for "$XEN_INT_BRIDGE_OR_NET_NAME")
+XEN_INTEGRATION_BRIDGE_DEFAULT=$(bridge_for "$XEN_INT_BRIDGE_OR_NET_NAME")
 append_kernel_cmdline \
     "$GUEST_NAME" \
-    "xen_integration_bridge=${XEN_INTEGRATION_BRIDGE}"
+    "xen_integration_bridge=${XEN_INTEGRATION_BRIDGE_DEFAULT}"
 
 FLAT_NETWORK_BRIDGE="${FLAT_NETWORK_BRIDGE:-$(bridge_for "$VM_BRIDGE_OR_NET_NAME")}"
 append_kernel_cmdline "$GUEST_NAME" "flat_network_bridge=${FLAT_NETWORK_BRIDGE}"