On Bionic ensure that a default storage backend is configured

Sets up the default dir backend and configures it as the default pool
for lxd.  This is required on bionic (LXD 3.0.x) as there is no default
storage pool by default.

Also installs apparmor which LXD requires to operate, but that is
missing from ubuntu image that is built for devstack-gate.

Related-Bug: 1822182
(Cherry-picked from aee3ef71d9)

Change-Id: I910d6f4b64990ff3068badc693321165317c10e3

contrib/ci/pre_test_hook.sh

@@ -21,6 +21,8 @@
 
 source $BASE/new/devstack/functions
 
-DEVSTACK_LOCAL_CONFIG+=$'\n'"LXD_BACKEND_DRIVER=zfs"
+# Note, due to Bug#1822182 we have to set this to default for the disk backend
+# otherwise rescue tests will not work.
+DEVSTACK_LOCAL_CONFIG+=$'\n'"LXD_BACKEND_DRIVER=default"
 
 export DEVSTACK_LOCAL_CONFIG

devstack/plugin.sh

@@ -13,7 +13,8 @@ NOVA_CONF_DIR=${NOVA_CONF_DIR:-/etc/nova}
 NOVA_CONF=${NOVA_CONF:-NOVA_CONF_DIR/nova.conf}
 
 # Configure LXD storage backends
-LXD_BACKEND_DRIVER=${LXD_BACKEND_DRIVER:default}
+# Note Bug:1822182 - ZFS backend is broken for Rescue's so don't use it!
+LXD_BACKEND_DRIVER=${LXD_BACKEND_DRIVER:-default}
 LXD_DISK_IMAGE=${DATA_DIR}/lxd.img
 LXD_ZFS_ZPOOL=devstack
 LXD_LOOPBACK_DISK_SIZE=${LXD_LOOPBACK_DISK_SIZE:-8G}
@@ -38,6 +39,14 @@ function pre_install_nova-lxd() {
         fi
 
         add_user_to_group $STACK_USER $LXD_GROUP
+
+        if [ "$DISTRO" == "bionic" ]; then
+            # install apparmor on the devstack image and restart lxd daemon
+            # the devstack-gate image that is built lacks apparmor, but LXD
+            # requires apparmor to work, so we add it back into the image.
+            sudo apt install -y apparmor apparmor-profiles-extra apparmor-utils
+            sudo systemctl restart lxd.service
+        fi
     fi
 }
 
@@ -51,6 +60,17 @@ function configure_nova-lxd() {
     iniset $NOVA_CONF DEFAULT compute_driver lxd.LXDDriver
     iniset $NOVA_CONF DEFAULT force_config_drive False
 
+    if [ "$LXD_BACKEND_DRIVER" == "zfs" ]; then
+        # For LXD 3 and upper we need pool name configured, see:
+        # bug/1782329
+        iniset $NOVA_CONF lxd pool $LXD_ZFS_ZPOOL
+    fi
+    if [ "$DISTRO-$LXD_BACKEND_DRIVER" == "bionic-default" ]; then
+        # for LXD 3 we need to have a pool name configured, and for default
+        # driver, it is 'default'
+        iniset $NOVA_CONF lxd pool default
+    fi
+
     if is_service_enabled glance; then
         iniset $GLANCE_API_CONF DEFAULT disk_formats "ami,ari,aki,vhd,raw,iso,qcow2,root-tar"
         iniset $GLANCE_API_CONF DEFAULT container_formats "ami,ari,aki,bare,ovf,tgz"
@@ -104,19 +124,28 @@ function test_config_nova-lxd() {
 }
 
 function configure_lxd_block() {
-   echo_summary "Configure LXD storage backend"
+    echo_summary "Configure LXD storage backend."
-   if is_ubuntu; then
+    if is_ubuntu; then
-      if [ "$LXD_BACKEND_DRIVER" == "default" ]; then
+        if [ "$LXD_BACKEND_DRIVER" == "default" ]; then
-         echo "Nothing to be done"
+            if [ "$DISTRO" == "bionic" ]; then
-      elif [ "$LXD_BACKEND_DRIVER" == "zfs" ]; then
+                echo_summary " . Configuring default dir backend for bionic lxd"
-         echo "Configuring ZFS backend"
+                sudo lxd init --auto --storage-backend dir
-         truncate -s $LXD_LOOPBACK_DISK_SIZE $LXD_DISK_IMAGE
+            fi
-         sudo apt-get install -y zfs
+        elif [ "$LXD_BACKEND_DRIVER" == "zfs" ]; then
-         lxd_dev=`sudo losetup --show -f ${LXD_DISK_IMAGE}`
+            pool=`lxc profile device get default root pool 2>> /dev/null || :`
-         sudo lxd init --auto --storage-backend zfs --storage-pool $LXD_ZFS_ZPOOL \
+            if [ "$pool" != "$LXD_ZFS_ZPOOL" ]; then
-              --storage-create-device $lxd_dev
+                echo_summary " . Configuring ZFS backend"
-      fi
+                truncate -s $LXD_LOOPBACK_DISK_SIZE $LXD_DISK_IMAGE
-   fi
+                # TODO(sahid): switch to use snap
+                sudo apt-get install -y zfsutils-linux
+                lxd_dev=`sudo losetup --show -f ${LXD_DISK_IMAGE}`
+                sudo lxd init --auto --storage-backend zfs --storage-pool $LXD_ZFS_ZPOOL \
+                    --storage-create-device $lxd_dev
+            else
+                echo_summary " . ZFS backend already configured"
+            fi
+        fi
+    fi
 }
 
 function shutdown_nova-lxd() {