private FailoverMetadata registerActiveContainerFailure(String activeContainerID, String activeContainerResourceID) {

    // this active container's resource ID is already registered, in which case update the metadata
    FailoverMetadata failoverMetadata;
    if (failovers.containsKey(activeContainerResourceID)) {
      failoverMetadata = failovers.get(activeContainerResourceID);
    } else {
      failoverMetadata = new FailoverMetadata(activeContainerID, activeContainerResourceID);
    }
    this.failovers.put(activeContainerResourceID, failoverMetadata);
    return failoverMetadata;
  }
Register the failure of an active container (identified by its resource ID).
samza-core/src/main/java/org/apache/samza/clustermanager/StandbyContainerManager.java