From 68ac03c7f269adda3739ef3cdb7a466f38e3b2b2 Mon Sep 17 00:00:00 2001
From: Mate Lakat <mate.lakat@citrix.com>
Date: Thu, 6 Jun 2013 16:22:34 +0100
Subject: [PATCH] xenapi: separate disk for cinder volumes

Some kernels have lockup issues while serving cinder volumes from
file-loopback-lvm kind of cinder setup. This patch provides a way to
create an additional drive to the OpenStack VM, and use that to store
cinder volumes, thus eliminating the lockup issue. It will help when
testing XenServer. Now, you can specify devices for stack-volumes
through:

    VOLUME_BACKING_DEVICE

In case you are using CINDER_MULTI_LVM_BACKEND, you can use

    VOLUME_BACKING_DEVICE2

as well.

Xenserver:
Should you whish to use a 10 gig disk backend for your cinder volumes,
specify:

    XEN_XVDB_SIZE_GB=10
    VOLUME_BACKING_DEVICE=/dev/xvdb

Citrix is using this approach on its internal CI system to run tests
against OpenStack. This is a workaround for this bug:

  https://bugs.launchpad.net/cinder/+bug/1023755

Related to blueprint xenapi-devstack-cleanup

Change-Id: Iee633d2704185bfbf9234882654c47b850fa168a
---
 lib/cinder                   | 35 ++++++++++++++++++++++-------------
 tools/xen/install_os_domU.sh | 13 +++++++++++++
 tools/xen/xenrc              | 10 ++++++++++
 3 files changed, 45 insertions(+), 13 deletions(-)

diff --git a/lib/cinder b/lib/cinder
index 0eabf400de..c572db49d2 100644
--- a/lib/cinder
+++ b/lib/cinder
@@ -69,10 +69,12 @@ CINDER_PERIODIC_INTERVAL=${CINDER_PERIODIC_INTERVAL:-60}
 # Name of the lvm volume groups to use/create for iscsi volumes
 VOLUME_GROUP=${VOLUME_GROUP:-stack-volumes}
 VOLUME_BACKING_FILE=${VOLUME_BACKING_FILE:-$DATA_DIR/${VOLUME_GROUP}-backing-file}
+VOLUME_BACKING_DEVICE=${VOLUME_BACKING_DEVICE:-}
 
 # VOLUME_GROUP2 is used only if CINDER_MULTI_LVM_BACKEND = True
 VOLUME_GROUP2=${VOLUME_GROUP2:-stack-volumes2}
 VOLUME_BACKING_FILE2=${VOLUME_BACKING_FILE2:-$DATA_DIR/${VOLUME_GROUP2}-backing-file}
+VOLUME_BACKING_DEVICE2=${VOLUME_BACKING_DEVICE2:-}
 
 VOLUME_NAME_PREFIX=${VOLUME_NAME_PREFIX:-volume-}
 
@@ -335,28 +337,35 @@ create_cinder_volume_group() {
     # ``/opt/stack/data``.
 
     if ! sudo vgs $VOLUME_GROUP; then
-        # Only create if the file doesn't already exists
-        [[ -f $VOLUME_BACKING_FILE ]] || truncate -s $VOLUME_BACKING_FILE_SIZE $VOLUME_BACKING_FILE
+        if [ -z "$VOLUME_BACKING_DEVICE" ]; then
+            # Only create if the file doesn't already exists
+            [[ -f $VOLUME_BACKING_FILE ]] || truncate -s $VOLUME_BACKING_FILE_SIZE $VOLUME_BACKING_FILE
+            DEV=`sudo losetup -f --show $VOLUME_BACKING_FILE`
 
-        DEV=`sudo losetup -f --show $VOLUME_BACKING_FILE`
-
-        # Only create if the loopback device doesn't contain $VOLUME_GROUP
-        if ! sudo vgs $VOLUME_GROUP; then
-            sudo vgcreate $VOLUME_GROUP $DEV
+            # Only create if the loopback device doesn't contain $VOLUME_GROUP
+            if ! sudo vgs $VOLUME_GROUP; then
+                sudo vgcreate $VOLUME_GROUP $DEV
+            fi
+        else
+            sudo vgcreate $VOLUME_GROUP $VOLUME_BACKING_DEVICE
         fi
     fi
     if [ "$CINDER_MULTI_LVM_BACKEND" = "True" ]; then
         #set up the second volume if CINDER_MULTI_LVM_BACKEND is enabled
 
         if ! sudo vgs $VOLUME_GROUP2; then
-            # Only create if the file doesn't already exists
-            [[ -f $VOLUME_BACKING_FILE2 ]] || truncate -s $VOLUME_BACKING_FILE_SIZE $VOLUME_BACKING_FILE2
+            if [ -z "$VOLUME_BACKING_DEVICE2" ]; then
+                # Only create if the file doesn't already exists
+                [[ -f $VOLUME_BACKING_FILE2 ]] || truncate -s $VOLUME_BACKING_FILE_SIZE $VOLUME_BACKING_FILE2
 
-            DEV=`sudo losetup -f --show $VOLUME_BACKING_FILE2`
+                DEV=`sudo losetup -f --show $VOLUME_BACKING_FILE2`
 
-            # Only create if the loopback device doesn't contain $VOLUME_GROUP
-            if ! sudo vgs $VOLUME_GROUP2; then
-                sudo vgcreate $VOLUME_GROUP2 $DEV
+                # Only create if the loopback device doesn't contain $VOLUME_GROUP
+                if ! sudo vgs $VOLUME_GROUP2; then
+                    sudo vgcreate $VOLUME_GROUP2 $DEV
+                fi
+            else
+                sudo vgcreate $VOLUME_GROUP2 $VOLUME_BACKING_DEVICE2
             fi
         fi
     fi
diff --git a/tools/xen/install_os_domU.sh b/tools/xen/install_os_domU.sh
index a744869288..be3b540d4b 100755
--- a/tools/xen/install_os_domU.sh
+++ b/tools/xen/install_os_domU.sh
@@ -259,6 +259,19 @@ fi
 FLAT_NETWORK_BRIDGE=$(bridge_for "$VM_BRIDGE_OR_NET_NAME")
 append_kernel_cmdline "$GUEST_NAME" "flat_network_bridge=${FLAT_NETWORK_BRIDGE}"
 
+# Add a separate xvdb, if it was requested
+if [[ "0" != "$XEN_XVDB_SIZE_GB" ]]; then
+    vm=$(xe vm-list name-label="$GUEST_NAME" --minimal)
+
+    # Add a new disk
+    localsr=$(get_local_sr)
+    extra_vdi=$(xe vdi-create \
+        name-label=xvdb-added-by-devstack \
+        virtual-size="${XEN_XVDB_SIZE_GB}GiB" \
+        sr-uuid=$localsr type=user)
+    xe vbd-create vm-uuid=$vm vdi-uuid=$extra_vdi device=1
+fi
+
 # create a snapshot before the first boot
 # to allow a quick re-run with the same settings
 xe vm-snapshot vm="$GUEST_NAME" new-name-label="$SNAME_FIRST_BOOT"
diff --git a/tools/xen/xenrc b/tools/xen/xenrc
index 0ed3a6a7e5..3e2396438a 100644
--- a/tools/xen/xenrc
+++ b/tools/xen/xenrc
@@ -76,4 +76,14 @@ UBUNTU_INST_NAMESERVERS=""
 UBUNTU_INST_NETMASK=""
 UBUNTU_INST_GATEWAY=""
 
+# Create a separate xvdb. Tis could be used as a backing device for cinder
+# volumes. Specify
+#   XEN_XVDB_SIZE_GB=10
+#   VOLUME_BACKING_DEVICE=/dev/xvdb
+# in your localrc to avoid kernel lockups:
+#   https://bugs.launchpad.net/cinder/+bug/1023755
+#
+# Set the size to 0 to avoid creation of additional disk.
+XEN_XVDB_SIZE_GB=0
+
 source ../../stackrc