Import Existing Clusters

Adding a config.yaml variable to allow existing ceph
monitor clusters to be imported. This patch will use
the config variable first and the get_mon_hosts function
second in order to determine which mons are in the cluster.

Change-Id: Ia06c509edb18615a9582f0184b03196a04ce9a0f

README.md

@@ -114,6 +114,8 @@ Please refer to the [Ceph Network Reference](http://docs.ceph.com/docs/master/ra
 
 **NOTE**: Existing deployments using ceph-*-network configuration options will continue to function; these options are preferred over any network space binding provided if set.
 
+**NOTE**: The mon-hosts field is only used to migrate existing clusters to a juju managed solution and should be left blank otherwise.
+
 # Contact Information
 
 ## Authors

config.yaml

@@ -56,6 +56,13 @@ options:
       How many nodes to wait for before trying to create the monitor cluster
       this number needs to be odd, and more than three is a waste except for
       very large clusters.
+  mon-hosts:
+    type: string
+    default:
+    description: |
+        A comma separated list of ceph mon hosts to use.  This field is only
+        used to migrate an existing cluster to a juju managed solution
+        and should be left blank otherwise.
   expected-osd-count:
     type: int
     default: 0

hooks/ceph_hooks.py

@@ -137,7 +137,7 @@ def get_ceph_context():
 
     cephcontext = {
         'auth_supported': config('auth-supported'),
-        'mon_hosts': ' '.join(get_mon_hosts()),
+        'mon_hosts': config('mon-hosts') or ' '.join(get_mon_hosts()),
         'fsid': leader_get('fsid'),
         'old_auth': cmp_pkgrevno('ceph', "0.51") < 0,
         'use_syslog': str(config('use-syslog')).lower(),
@@ -468,7 +468,7 @@ def admin_relation_joined(relid=None):
         data = {'key': ceph.get_named_key(name=name, caps=ceph.admin_caps),
                 'fsid': leader_get('fsid'),
                 'auth': config('auth-supported'),
-                'mon_hosts': " ".join(get_mon_hosts())
+                'mon_hosts': config('mon-hosts') or " ".join(get_mon_hosts())
                 }
         relation_set(relation_id=relid,
                      relation_settings=data)

unit_tests/test_ceph_hooks.py

@@ -22,6 +22,7 @@ CHARM_CONFIG = {'config-flags': '',
                 'osd-journal-size': 1024,
                 'use-direct-io': True,
                 'osd-format': 'ext4',
+                'mon-hosts': '',
                 'prefer-ipv6': False}