Add support for Storage hooks

This adds support for Juju's storage hooks by merging the config
provided osd-devices with Juju storage provided osd-devices, in the
same way that the existing Ceph charm handles them.

In addition to providing support for ceph-osds via Juju storage,
we provide support for multiple journal devices through Juju storage
as well.

We have to add a shim hook to ensure that Ceph is installed prior
to storage hook invocation because storage attached at deploy time
will execute hooks before the install hook

Change-Id: Idad46e8f4cc32e09fbd64d29cd93745662e9f542

config.yaml

@@ -10,7 +10,8 @@ options:
       The devices to format and set up as osd volumes.
 
       These devices are the range of devices that will be checked for and
-      used across all service units.
+      used across all service units, in addition to any volumes attached
+      via the --storage flag during deployment.
 
       For ceph >= 0.56.6 these can also be directories instead of devices - the
       charm assumes anything not starting with /dev is a directory instead.

hooks/add-storage

@@ -0,0 +1,7 @@
+#!/bin/bash
+# Wrapper to deal with newer Ubuntu versions that don't have py2 installed
+# by default.
+
+dpkg -l|grep 'python-apt ' || exit 0
+
+exec ./hooks/storage.real

hooks/ceph_hooks.py

@@ -31,6 +31,8 @@ from charmhelpers.core.hookenv import (
     UnregisteredHookError,
     service_name,
     status_set,
+    storage_get,
+    storage_list,
 )
 from charmhelpers.core.host import (
     umount,
@@ -379,6 +381,7 @@ def config_changed():
     prepare_disks_and_activate()
 
 
+@hooks.hook('storage.real')
 def prepare_disks_and_activate():
     osd_journal = get_journal_devices()
     check_overlap(osd_journal, set(get_devices()))
@@ -447,20 +450,31 @@ def reformat_osd():
 
 def get_devices():
     if config('osd-devices'):
-        return [
+        devices = [
             os.path.realpath(path)
             for path in config('osd-devices').split(' ')]
     else:
-        return []
+        devices = []
+
+    # List storage instances for the 'osd-devices'
+    # store declared for this charm too, and add
+    # their block device paths to the list.
+    storage_ids = storage_list('osd-devices')
+    devices.extend((storage_get('location', s) for s in storage_ids))
+    return devices
 
 
 def get_journal_devices():
-    osd_journal = config('osd-journal')
-    if not osd_journal:
-        return set()
-    osd_journal = [l.strip() for l in config('osd-journal').split(' ')]
-    osd_journal = set(filter(os.path.exists, osd_journal))
-    return osd_journal
+    if config('osd-journal'):
+        devices = config('osd-journal')
+        devices = [l.strip() for l in config('osd-journal').split(' ')]
+    else:
+        devices = []
+    storage_ids = storage_list('osd-journals')
+    devices.extend((storage_get('location', s) for s in storage_ids))
+    devices = filter(os.path.exists, devices)
+
+    return set(devices)
 
 
 @hooks.hook('mon-relation-changed',

hooks/osd-devices-storage-attached

@@ -0,0 +1 @@
+add-storage

hooks/osd-devices-storage-detaching

@@ -0,0 +1 @@
+add-storage

hooks/storage.real

@@ -0,0 +1 @@
+ceph_hooks.py

metadata.yaml

@@ -19,3 +19,12 @@ description: |
 requires:
   mon:
     interface: ceph-osd
+storage:
+  osd-devices:
+    type: block
+    multiple:
+      range: 0-
+  osd-journals:
+    type: block
+    multiple:
+      range: 0-