default ClusterMetrics getClusterMetrics() throws IOException {
    return getClusterMetrics(EnumSet.allOf(ClusterMetrics.Option.class));
  }
Get whole cluster metrics, containing status about:

<pre>
hbase version
cluster id
primary/backup master(s)
master's coprocessors
live/dead regionservers
balancer
regions in transition
</pre>

@return cluster metrics
@throws IOException if a remote or network exception occurs
hbase-client/src/main/java/org/apache/hadoop/hbase/client/Admin.java