support drain/undrain feature server from cluster

lib/utils/sbc-pinger.js

@@ -166,9 +166,23 @@ module.exports = (logger) => {
     }, 1000);
   }
 
+  const setDryUpCalls = () => {
+    logger.info('setting dryUpCalls flag');
+    dryUpCalls = true;
+  };
+
+  const clearDryUpCalls = () => {
+    if (lifecycleEmitter.operationalState !== LifeCycleEvents.ScaleIn) {
+      logger.info('clearing dryUpCalls flag');
+      dryUpCalls = false;
+    }
+  };
+
   return {
     lifecycleEmitter,
-    getSBC: () => sbcs[idxSbc++ % sbcs.length]
+    getSBC: () => sbcs[idxSbc++ % sbcs.length],
+    setDryUpCalls,
+    clearDryUpCalls,
   };
 };