Factor out tgt-specific parts of cinder element

RHEL is only going to support the lio iscsi helper, so the tgt
parts of the element are not going to work there.  A subsequent
change will add a corresponding cinder-lio element to support that.

When this merges, the corresponding change to tripleo-incubator in
I1e33af0cb78fa9477bc5a0b9b89b06b907b81fae must merge as well to
prevent breakage of devtest.

Change-Id: Ic032204076adfa0d30b09423f2a46b587e07400d

elements/cinder-tgt/README.md

@@ -0,0 +1,4 @@
+Use tgtd as the iscsi helper for cinder.
+
+The cinder.iscsi-target configuration option must be set to "tgtadm".  See the cinder
+element readme for details.

elements/cinder-tgt/element-deps

@@ -0,0 +1 @@
+cinder

elements/cinder-tgt/install.d/72-cinder-tgt

@@ -0,0 +1,8 @@
+#!/bin/bash
+
+set -eux
+
+install-packages tgt
+
+mkdir -p /etc/tgt/conf.d
+echo 'include /mnt/state/var/lib/cinder/volumes/*' > /etc/tgt/conf.d/cinder.conf

elements/cinder-tgt/os-refresh-config/post-configure.d/74-cinder-tgt

@@ -0,0 +1,5 @@
+#!/bin/bash
+
+set -eu
+
+os-svc-restart -n tgt

elements/cinder-volume/os-refresh-config/post-configure.d/74-cinder-volume

@@ -2,5 +2,4 @@
 set -eu
 
 os-svc-enable -n cinder-volume
-os-svc-restart -n tgt
 os-svc-restart -n cinder-volume

elements/cinder/README.md

@@ -1,5 +1,8 @@
 Install cinder service from git.
 
+An appropriate target element (such as cinder-tgt or cinder-lio) must be included
+in images that use cinder.
+
 Configuration
 -------------
 
@@ -7,4 +10,6 @@ cinder:
   verbose: False
     - Print more verbose output (set logging level to INFO instead of default WARNING level).
   debug: False
-    - Print debugging output (set logging level to DEBUG instead of default WARNING level).
+    - Print debugging output (set logging level to DEBUG instead of default WARNING level).
+  iscsi-helper: tgtadm
+    - Specifies the iSCSI helper to use.  Must match the target element included in the image.

elements/cinder/install.d/73-cinder

@@ -2,8 +2,6 @@
 
 set -eux
 
-mkdir -p /etc/tgt/conf.d
 install -d -o root -g cinder -m 0770 /var/lib/cinder/volumes
 install -d -o root -g cinder -m 0770 /var/lib/cinder/nfs
 register-state-path /var/lib/cinder
-echo 'include /mnt/state/var/lib/cinder/volumes/*' > /etc/tgt/conf.d/cinder.conf

elements/cinder/install.d/cinder-source-install/72-cinder

@@ -1,7 +1,7 @@
 #!/bin/bash
 set -eux
 
-install-packages lvm2 libssl-dev tgt libffi-dev nfs-common
+install-packages lvm2 libssl-dev libffi-dev nfs-common
 echo "qpid-python" | tee -a /opt/stack/cinder/requirements.txt
 os-svc-install -i "$CINDER_VENV_DIR" -u cinder -r /opt/stack/cinder