private InstanceConfig getInstanceConfig() {
    InstanceConfig instanceConfig = helixAdmin.getInstanceConfig(clusterName, instanceName);
    if (instanceConfig == null) {
      throw new IllegalStateException(
          "No instance config found for cluster: \"" + clusterName + "\", instance: \"" + instanceName + "\"");
    }
    return instanceConfig;
  }
@return {@link InstanceConfig} of current participant (The method also checks the existence of InstanceConfig).
ambry-clustermap/src/main/java/com/github/ambry/clustermap/HelixParticipant.java