anchor.diff:  === Canary
   
   There is a Canary class can help users to canary-test the HBase cluster status, with every column-family for every regions or RegionServer's granularity.
  -To see the usage, use the `--help` parameter.
  +To see the usage, use the `-help` parameter.
   
   ----
   $ ${HBASE_HOME}/bin/hbase canary -help
  
positive.code: with the `-treatFailureAsError` option. When enabled, read / write failure would result in error
  exit code.
  ----
  $ ${HBASE_HOME}/bin/hbase canary --treatFailureAsError
  ----
  
  ==== Running Canary in a Kerberos-enabled Cluster
  
negative.code:   <value>/etc/hbase/conf/keytab.krb5</value>
  </property>
  <!-- optional params -->
  <property>
    <name>hbase.client.dns.interface</name>
    <value>default</value>
  </property>
  