Unhardcoding disk_cachemodes nova option

Change-Id: Ia327b4a13b40d3e8e136045190597bbb3c5a84cd
diff --git a/README.rst b/README.rst
index f7102e1..ac97a5c 100644
--- a/README.rst
+++ b/README.rst
@@ -157,6 +157,7 @@
         version: juno
         enabled: true
         virtualization: kvm
+        disk_cachemodes: network=writeback,block=none
         availability_zone: availability_zone_01
         aggregates:
         - hosts_with_fc
diff --git a/nova/files/liberty/nova-compute.conf.Debian b/nova/files/liberty/nova-compute.conf.Debian
index d46e93b..1859061 100644
--- a/nova/files/liberty/nova-compute.conf.Debian
+++ b/nova/files/liberty/nova-compute.conf.Debian
@@ -201,7 +201,7 @@
 
 {%- if compute.get('ceph', {}).ephemeral is defined %}
 [libvirt]
-disk_cachemodes="network=writeback,block=none"
+disk_cachemodes="{{ compute.get('disk_cachemodes', 'network=writeback,block=none') }}"
 cpu_mode=host-passthrough
 virt_type=kvm
 live_migration_flag=VIR_MIGRATE_UNDEFINE_SOURCE,VIR_MIGRATE_PEER2PEER,VIR_MIGRATE_LIVE,VIR_MIGRATE_PERSIST_DEST
diff --git a/nova/files/mitaka/nova-compute.conf.Debian b/nova/files/mitaka/nova-compute.conf.Debian
index 561c2c3..fabad22 100644
--- a/nova/files/mitaka/nova-compute.conf.Debian
+++ b/nova/files/mitaka/nova-compute.conf.Debian
@@ -118,7 +118,7 @@
 virt_type = kvm
 inject_partition=-2
 inject_password=False
-disk_cachemodes="network=writeback,block=none"
+disk_cachemodes="{{ compute.get('disk_cachemodes', 'network=writeback,block=none') }}"
 libvirt_inject_password=True
 block_migration_flag=VIR_MIGRATE_UNDEFINE_SOURCE,VIR_MIGRATE_PEER2PEER,VIR_MIGRATE_LIVE,VIR_MIGRATE_NON_SHARED_INC
 live_migration_flag=VIR_MIGRATE_UNDEFINE_SOURCE,VIR_MIGRATE_PEER2PEER,VIR_MIGRATE_LIVE,VIR_MIGRATE_PERSIST_DEST
diff --git a/nova/files/newton/nova-compute.conf.Debian b/nova/files/newton/nova-compute.conf.Debian
index 6de6cf4..34afc4c 100644
--- a/nova/files/newton/nova-compute.conf.Debian
+++ b/nova/files/newton/nova-compute.conf.Debian
@@ -143,7 +143,7 @@
 virt_type = kvm
 inject_partition=-2
 inject_password=False
-disk_cachemodes="network=writeback,block=none"
+disk_cachemodes="{{ compute.get('disk_cachemodes', 'network=writeback,block=none') }}"
 libvirt_inject_password=True
 block_migration_flag=VIR_MIGRATE_UNDEFINE_SOURCE,VIR_MIGRATE_PEER2PEER,VIR_MIGRATE_LIVE,VIR_MIGRATE_NON_SHARED_INC
 live_migration_flag=VIR_MIGRATE_UNDEFINE_SOURCE,VIR_MIGRATE_PEER2PEER,VIR_MIGRATE_LIVE,VIR_MIGRATE_PERSIST_DEST
diff --git a/nova/files/ocata/nova-compute.conf.Debian b/nova/files/ocata/nova-compute.conf.Debian
index 6fb1421..b9f41be 100644
--- a/nova/files/ocata/nova-compute.conf.Debian
+++ b/nova/files/ocata/nova-compute.conf.Debian
@@ -5899,7 +5899,7 @@
 virt_type = kvm
 inject_partition=-2
 inject_password=True
-disk_cachemodes="network=writeback,block=none"
+disk_cachemodes="{{ compute.get('disk_cachemodes', 'network=writeback,block=none') }}"
 block_migration_flag=VIR_MIGRATE_UNDEFINE_SOURCE,VIR_MIGRATE_PEER2PEER,VIR_MIGRATE_LIVE,VIR_MIGRATE_NON_SHARED_INC
 live_migration_flag=VIR_MIGRATE_UNDEFINE_SOURCE,VIR_MIGRATE_PEER2PEER,VIR_MIGRATE_LIVE,VIR_MIGRATE_PERSIST_DEST
 inject_key=True
diff --git a/tests/pillar/compute_cluster.sls b/tests/pillar/compute_cluster.sls
index 1a3335f..2bcd9b4 100644
--- a/tests/pillar/compute_cluster.sls
+++ b/tests/pillar/compute_cluster.sls
@@ -7,6 +7,7 @@
       mount_points:
       - path: /mnt/hugepages_1GB
     virtualization: kvm
+    disk_cachemodes: network=writeback,block=none
     heal_instance_info_cache_interval: 60
     vncproxy_url: openstack:6080
     report_interval: 60