Make sure ceph-mds is deployed (needed for manila).

As we need only one ceph-mds node, let's take it first and we can
both make sure that there's one deployed and skip those complicated
checks for conflicts using the extra method.

(cherry picked from commit 7f61904)

Author: jsuchome

crowbar_framework/app/models/ceph_service.rb

@@ -106,27 +106,6 @@ def proposal_dependencies(role)
     answer
   end
 
-  # Helper to find a suitable node for ceph-mds role.
-  # ceph-mds conflicts with ceph-osd, and should not be assigned to the cluster node
-  def select_node_for_mds_role(nodes)
-    # do not modify array given by caller
-    mds_nodes = nodes.dup
-    mds_nodes.delete_if(&:nil?)
-    mds_nodes.reject! do |n|
-      node_is_valid_for_role(n.name, "ceph-mds")
-    end
-
-    mds_node = mds_nodes.find { |n| n.intended_role != "controller" }
-    if mds_node.nil? && !mds_nodes.empty?
-      mds_node = mds_nodes.first
-      @logger.debug("Not enough nodes: putting ceph-mds on controller node (unsupported scenario)")
-    end
-    if mds_node.nil?
-      @logger.warn("Not enough nodes: there seems to be no node for ceph-mds role!")
-    end
-    mds_node
-  end
-
   def create_proposal
     @logger.debug("Ceph create_proposal: entering")
     base = super
@@ -142,9 +121,11 @@ def create_proposal
       n.roles.include?("pacemaker-cluster-member")
     end
 
-    osd_nodes = select_nodes_for_role(nodes, "ceph-osd", "storage")
+    mds_node = select_nodes_for_role(nodes, "ceph-mds").first
+
+    osd_nodes = select_nodes_for_role(nodes - [mds_node], "ceph-osd", "storage")
     if osd_nodes.size < 2
-      osd_nodes_all = select_nodes_for_role(nodes, "ceph-osd")
+      osd_nodes_all = select_nodes_for_role(nodes - [mds_node], "ceph-osd")
       # avoid controllers if possible (ceph should not be used with openstack roles)
       osd_nodes_no_controller = osd_nodes_all.reject do |n|
         n.intended_role == "controller"
@@ -163,8 +144,6 @@ def create_proposal
     end
     mon_nodes = mon_nodes.take(mon_nodes.length > 2 ? 3 : 1)
 
-    mds_node = select_node_for_mds_role(nodes - osd_nodes)
-
     radosgw_node = select_nodes_for_role(nodes, "ceph-radosgw", "storage").first
 
     # Any spare node after allocating mons and osds is fair game