public synchronized void updateStandbyContainer(String standbyContainerResourceID, String standbyContainerHost) {
      this.selectedStandbyContainers.put(standbyContainerResourceID, standbyContainerHost);
    }
Encapsulates metadata concerning the failover of an active container.
samza-core/src/main/java/org/apache/samza/clustermanager/StandbyContainerManager.java