public void setFailReason(String failReason) {
    m_failReason = failReason;
  }
Sets the full rendered, human-readable failure reason, if any.

@param failReason
         the failure reason, if any, or {@code null} for none.
ambari-server-spi/src/main/java/org/apache/ambari/spi/upgrade/UpgradeCheckResult.java