Make nova-compute-network use a data volume container

A data volume container is far superior to bind mounting the
host's shared directories.  It preserves the idempotency,
immutability and declarative properties of the containers.

The way this works in practice is that a data volume container is
created.  Then when the containers start they use LVM to access
the filesystem where /var/lib/docker is contained.  Then the
container startup logic bindmounts the data volume stored on the
host filesystem in /var/lib/docker/vfs/dir/ID.  This prevents
people with access to the host operating system from damaging
the contents of the data container.

It does mean that now we must use tools/stop to stop our containers
rather than tools/cleanup-containers -f.

This is a containers best practice.  For more details see:

https://docs.docker.com/userguide/dockervolumes/

Big credit goes to Danyeon Hansen for seeding this idea in the
mariadb containers.

Note occasionally docker-compose start/stop seems to not want to stop
a container.  This bug needs to be addressed upstream separately
from our utilization of this best practice.

Change-Id: Iaa1419f606e1b1b7a7560a095c49e79d643164f1

compose/nova-compute-network.yml

+computedata:
+   image: kollaglue/centos-rdo-nova-compute-data
+   name: computedata
+
 libvirt:
    image: kollaglue/centos-rdo-nova-libvirt
    name: libvirt
@@ -10,9 +14,8 @@ libvirt:
    volumes:
     - /run:/run
     - /sys/fs/cgroup:/sys/fs/cgroup
-    - /var/lib/nova:/var/lib/nova
-    - /var/lib/libvirt:/var/lib/libvirt
-    - /etc/libvirt/qemu:/etc/libvirt/qemu
+   volumes_from:
+    - computedata
 
 novanetwork:
    image: kollaglue/centos-rdo-nova-network
@@ -25,8 +28,8 @@ novanetwork:
    volumes:
     - /run:/run
     - /sys/fs/cgroup:/sys/fs/cgroup
-    - /var/lib/nova:/var/lib/nova
-    - /var/lib/libvirt:/var/lib/libvirt
+   volumes_from:
+    - computedata
 
 novacompute:
    image: kollaglue/centos-rdo-nova-compute
@@ -39,6 +42,5 @@ novacompute:
    volumes:
     - /run:/run
     - /sys/fs/cgroup:/sys/fs/cgroup
-    - /var/lib/nova:/var/lib/nova
-    - /var/lib/libvirt:/var/lib/libvirt
-    - /etc/libvirt/qemu:/etc/libvirt/qemu
+   volumes_from:
+    - computedata

docker/nova-compute/nova-compute-data/Dockerfile

+FROM %%KOLLA_NAMESPACE%%/%%KOLLA_PREFIX%%base
+MAINTAINER Kolla Project (https://launchpad.net/kolla)
+
+VOLUME [ "/var/lib/nova" ]
+VOLUME [ "/var/lib/libvirt" ]
+VOLUME [ "/etc/libvirt/qemu" ]
+
+# Command needed to start the data container.
+# Note: data containers do not need to be persistent.
+CMD ["/bin/true"]

docker/nova-compute/nova-compute-data/build

+../../../tools/build-docker-image
\ No newline at end of file

docker/nova-compute/nova-compute/Dockerfile

@@ -9,7 +9,5 @@ ADD config-nova-compute.sh /opt/kolla/config-nova-compute.sh
 ADD ./start.sh /start.sh
 
 VOLUME [ "/sys/fs/cgroup" ]
-VOLUME [ "/var/lib/nova" ]
-VOLUME [ "/var/lib/libvirt" ]
 
 CMD ["/start.sh"]

docker/nova-compute/nova-libvirt/Dockerfile

@@ -6,7 +6,6 @@ RUN yum -y install libvirtd libguestfs qemu-system-x86 \
         libvirt-daemon-config-nwfilter; yum clean all
 
 VOLUME [ "/sys/fs/cgroup" ]
-VOLUME [ "/var/lib/nova" ]
 
 ADD ./start.sh /start.sh
 

docker/nova-compute/nova-network/Dockerfile

@@ -7,7 +7,4 @@ RUN yum -y install openstack-nova-network \
 ADD config-nova-network.sh /opt/kolla/config-nova-network.sh
 ADD ./start.sh /start.sh
 
-VOLUME [ "/var/lib/nova" ]
-VOLUME [ "/var/lib/libvirt" ]
-
 CMD ["/start.sh"]