From a6638ce3bf633e8abc6e52b030d9d1c12338f9b4 Mon Sep 17 00:00:00 2001
From: Andrew McLeod <andrew.mcleod@canonical.com>
Date: Fri, 20 Oct 2017 16:55:05 -0600
Subject: [PATCH] Add charm config option for force_raw_images

Since Ocata, backing images are by default converted into raw format
but since Pike a problem with O_DIRECT calls and ZFS backend storage
has presented - i.e., Pike on LXD with ZFS backend storage will result
in an error about image conversion. This config option allows
that default to be changed so that Pike on LXD with ZFS will lauch
instances succesfully.

Closes-Bug: 1710994

Change-Id: Ieba15b44b4b56a356d58c4504dd259fc80e7575d
---
 config.yaml                              |  8 ++++++++
 hooks/nova_compute_context.py            |  2 ++
 templates/ocata/nova.conf                |  1 +
 unit_tests/test_nova_compute_contexts.py | 24 ++++++++++++++++++++++++
 4 files changed, 35 insertions(+)

diff --git a/config.yaml b/config.yaml
index 3aab612b..f4eaf824 100644
--- a/config.yaml
+++ b/config.yaml
@@ -273,6 +273,14 @@ options:
       Tell Nova which libvirt image backend to use. Supported backends are rbd,
       lvm and qcow2. If no backend is specified, the Nova default (qcow2) is
       used. Note that rbd imagebackend is only supported with >= Juno.
+  force-raw-images:
+    type: boolean
+    default: True
+    description: |
+      Force conversion of backing images to raw format. Note that the conversion
+      process in Pike uses O_DIRECT calls - certain file systems do not support this,
+      for example ZFS; e.g. if using the LXD provider with ZFS backend, this option
+      should be set to False.
   rbd-pool:
     type: string
     default: 'nova'
diff --git a/hooks/nova_compute_context.py b/hooks/nova_compute_context.py
index a80dbbc3..3d905a61 100644
--- a/hooks/nova_compute_context.py
+++ b/hooks/nova_compute_context.py
@@ -244,6 +244,8 @@ class NovaComputeLibvirtContext(context.OSContextGenerator):
         if config('libvirt-image-backend'):
             ctxt['libvirt_images_type'] = config('libvirt-image-backend')
 
+        ctxt['force_raw_images'] = config('force-raw-images')
+
         return ctxt
 
 
diff --git a/templates/ocata/nova.conf b/templates/ocata/nova.conf
index 75f9bfbc..5a24baef 100644
--- a/templates/ocata/nova.conf
+++ b/templates/ocata/nova.conf
@@ -20,6 +20,7 @@ api_paste_config=/etc/nova/api-paste.ini
 enabled_apis=osapi_compute,metadata
 auth_strategy=keystone
 my_ip = {{ host_ip }}
+force_raw_images = {{ force_raw_images }}
 
 {% if arch == 'aarch64' -%}
 libvirt_use_virtio_for_bridges=False
diff --git a/unit_tests/test_nova_compute_contexts.py b/unit_tests/test_nova_compute_contexts.py
index 00d6a05a..bffde8dd 100644
--- a/unit_tests/test_nova_compute_contexts.py
+++ b/unit_tests/test_nova_compute_contexts.py
@@ -225,6 +225,7 @@ class NovaComputeContextTests(CharmTestCase):
              'kvm_hugepages': 0,
              'listen_tls': 0,
              'host_uuid': self.host_uuid,
+             'force_raw_images': True,
              'reserved_host_memory': 512}, libvirt())
 
     def test_libvirt_bin_context_no_migration(self):
@@ -241,6 +242,7 @@ class NovaComputeContextTests(CharmTestCase):
              'kvm_hugepages': 0,
              'listen_tls': 0,
              'host_uuid': self.host_uuid,
+             'force_raw_images': True,
              'reserved_host_memory': 512}, libvirt())
 
     def test_libvirt_bin_context_migration_tcp_listen(self):
@@ -258,6 +260,7 @@ class NovaComputeContextTests(CharmTestCase):
              'listen_tls': 0,
              'host_uuid': self.host_uuid,
              'live_migration_uri': 'qemu+ssh://%s/system',
+             'force_raw_images': True,
              'reserved_host_memory': 512}, libvirt())
 
     def test_libvirt_disk_cachemodes(self):
@@ -275,6 +278,7 @@ class NovaComputeContextTests(CharmTestCase):
              'kvm_hugepages': 0,
              'listen_tls': 0,
              'host_uuid': self.host_uuid,
+             'force_raw_images': True,
              'reserved_host_memory': 512}, libvirt())
 
     def test_libvirt_hugepages(self):
@@ -293,6 +297,25 @@ class NovaComputeContextTests(CharmTestCase):
              'kvm_hugepages': 1,
              'listen_tls': 0,
              'host_uuid': self.host_uuid,
+             'force_raw_images': True,
+             'reserved_host_memory': 512}, libvirt())
+
+    def test_libvirt_context_libvirtd_force_raw_images(self):
+        self.lsb_release.return_value = {'DISTRIB_CODENAME': 'zesty'}
+        self.os_release.return_value = 'ocata'
+        self.kv.return_value = FakeUnitdata(**{'host_uuid': self.host_uuid})
+        self.test_config.set('force-raw-images', False)
+        libvirt = context.NovaComputeLibvirtContext()
+
+        self.assertEqual(
+            {'libvirtd_opts': '',
+             'libvirt_user': 'libvirt',
+             'arch': platform.machine(),
+             'ksm': 'AUTO',
+             'kvm_hugepages': 0,
+             'listen_tls': 0,
+             'host_uuid': self.host_uuid,
+             'force_raw_images': False,
              'reserved_host_memory': 512}, libvirt())
 
     def test_lxd_live_migration_opts_xenial(self):
@@ -396,6 +419,7 @@ class NovaComputeContextTests(CharmTestCase):
              'host_uuid': self.host_uuid,
              'reserved_host_memory': 1024,
              'vcpu_pin_set': '^0^2',
+             'force_raw_images': True,
              'pci_passthrough_whitelist': 'mypcidevices'}, libvirt())
 
     def test_ksm_configs(self):