tasks/ceph: add ceph.stop task

So that we can explicitly stop daemons on demand.  Useful
for MDS tool tests that want the MDS daemons not to be running,
is this is more solid and explicit than doing e.g. "ceph mds
stop" from within workunits.

Signed-off-by: John Spray <john.spray@redhat.com>

tasks/ceph.py

@@ -21,6 +21,7 @@ from teuthology.orchestra.run import CommandFailedError
 from teuthology.orchestra.daemon import DaemonGroup
 
 DEFAULT_CONF_PATH = '/etc/ceph/ceph.conf'
+CEPH_ROLE_TYPES = ['mon', 'osd', 'mds', 'rgw']
 
 log = logging.getLogger(__name__)
 
@@ -1049,7 +1050,7 @@ def restart(ctx, config):
 
    For example::
       tasks:
-      - ceph.restart: [osd.0, mon.1]
+      - ceph.restart: [osd.0, mon.1, mds.*]
 
    or::
 
@@ -1064,19 +1065,11 @@ def restart(ctx, config):
     """
     if config is None:
         config = {}
-    if isinstance(config, list):
-        config = { 'daemons': config }
-    if 'daemons' not in config:
-        config['daemons'] = []
-        type_daemon = ['mon', 'osd', 'mds', 'rgw']
-        for d in type_daemon:
-            type_ = d
-            for daemon in ctx.daemons.iter_daemons_of_role(type_):
-                config['daemons'].append(type_ + '.' + daemon.id_)
+    elif isinstance(config, list):
+        config = {'daemons': config}
 
-    assert isinstance(config['daemons'], list)
-    daemons = dict.fromkeys(config['daemons'])
-    for i in daemons.keys():
+    daemons = ctx.daemons.resolve_role_list(config.get('daemons', None), CEPH_ROLE_TYPES)
+    for i in daemons:
         type_ = i.split('.', 1)[0]
         id_ = i.split('.', 1)[1]
         ctx.daemons.get_daemon(type_, id_).stop()
@@ -1088,6 +1081,38 @@ def restart(ctx, config):
         wait_for_osds_up(ctx=ctx, config=None)
     yield
 
+
+@contextlib.contextmanager
+def stop(ctx, config):
+    """
+    Stop ceph daemons
+
+    For example::
+      tasks:
+      - ceph.stop: [mds.*]
+
+      tasks:
+      - ceph.stop: [osd.0, osd.2]
+
+      tasks:
+      - ceph.stop:
+          daemons: [osd.0, osd.2]
+
+    """
+    if config is None:
+        config = {}
+    elif isinstance(config, list):
+        config = {'daemons': config}
+
+    daemons = ctx.daemons.resolve_role_list(config.get('daemons', None), CEPH_ROLE_TYPES)
+    for i in daemons:
+        type_ = i.split('.', 1)[0]
+        id_ = i.split('.', 1)[1]
+        ctx.daemons.get_daemon(type_, id_).stop()
+
+    yield
+
+
 @contextlib.contextmanager
 def task(ctx, config):
     """