public boolean isUpgradePrecheckBypass() {
    return Boolean.parseBoolean(getProperty(STACK_UPGRADE_BYPASS_PRECHECKS));
  }
Determine whether or not a Rolling/Express upgrade can bypass the PreChecks. Default value should be false.

@return true if RU/EU can bypass PreChecks, otherwise, false.
ambari-server/src/main/java/org/apache/ambari/server/configuration/Configuration.java