Clear out the cache entirely on master->non-master

Author: joegallo

x-pack/plugin/ilm/src/main/java/org/elasticsearch/xpack/ilm/IndexLifecycleService.java

@@ -303,6 +303,7 @@ public void clusterChanged(ClusterChangedEvent event) {
             } else {
                 // we were the master, and now we aren't
                 cancelJob();
+                policyRegistry.clear();
             }
         }
 

x-pack/plugin/ilm/src/main/java/org/elasticsearch/xpack/ilm/PolicyStepsRegistry.java

@@ -163,6 +163,18 @@ public void delete(Index deleted) {
         cachedSteps.remove(deleted);
     }
 
+    /**
+     * Clear internal maps that were populated by update (and others).
+     */
+    public void clear() {
+        // this is potentially large, so it's important to clear it
+        cachedSteps.clear();
+        // these are relatively small, but there's no harm in clearing them
+        lifecyclePolicyMap.clear();
+        firstStepMap.clear();
+        stepMap.clear();
+    }
+
     /**
      * Return all ordered steps for the current policy for the index. Does not
      * resolve steps using the phase caching, but only for the currently existing policy.