private String pidFilePath(ServerType serverType, int port) {
    String dir = serverWorkingDir(serverType, port);
    String user = System.getenv("USER");
    String pidFile = String.format("%s/hbase-%s-%s.pid", dir, user, serverType.fullName);
    return pidFile;
  }
Generates a list of random port numbers in the sorted order. A sorted order makes sense if we
ever want to refer to these servers by their index in the returned array, e.g. server #0, #1,
etc.
hbase-diagnostics/src/test/java/org/apache/hadoop/hbase/util/ProcessBasedLocalHBaseCluster.java