@JsonProperty("units")
  public String getUnits() {
    return m_units;
  }
Gets a label identifying the units that the values are in. For example,
this could be "s" for seconds or GB for "Gigabytes".

@return the units, or {@code null} for none.
ambari-server/src/main/java/org/apache/ambari/server/state/alert/Reporting.java