@Override
    public void start(CoprocessorEnvironment env) throws IOException {
      if (env instanceof MasterCoprocessorEnvironment) {
        MetricRegistry registry = ((MasterCoprocessorEnvironment) env).getMetricRegistryForMaster();

        createTableTimer = registry.timer("CreateTable");
      }
    }
MasterObserver that has a Timer metric for create table operation.
hbase-server/src/test/java/org/apache/hadoop/hbase/coprocessor/TestCoprocessorMetrics.java