make ssh port in alluxio.cli.validation.SshValidationTask configurable

Description

When doing validateEnv command for a cluster, there will be a "Validating ssh.masters.reachable" and "Validating ssh.workers.reachable" stage which will check if the master can successfully ssh to the specify worker host
the method is "alluxio.cli.validation.SshValidationTask" which will hardcode the ssh port to 22

public final class SshValidationTask extends AbstractValidationTask {
  private final String mFileName;

  /**
   * Creates a new instance of {@link SshValidationTask}.
   *
   * @param fileName file name for a node list file (e.g. conf/workers, conf/masters)
   */
  public SshValidationTask(String fileName) {
    mFileName = fileName;
  }

  @Override
  public TaskResult validate(Map<String, String> optionsMap) {
    List<String> nodes = Utils.readNodeList(mFileName);
    if (nodes == null) {
      return TaskResult.FAILED;
    }

    boolean hasUnreachableNodes = false;
    for (String nodeName : nodes) {
      if (!Utils.isAddressReachable(nodeName, 22)) {
        System.err.format("Unable to reach ssh port 22 on node %s.%n", nodeName);
        hasUnreachableNodes = true;
      }
    }
    return hasUnreachableNodes ? TaskResult.WARNING : TaskResult.OK;
  }
}

in typical Enterprise environment,for the sake of security, the default ssh port of 22 will usually change to a non-typical port
IMO, it is reasonable to have a configuration for the ssh port with a default value of 22

Environment

alluxio version: 1.8.1
os version: debian 8.9
hadoop version: cdh5.6.0-hadoop2.6.0

Status

Assignee

Calvin Jia

Reporter

Shuang Li (louShang)

Labels

None

Components

Core - Client

Affects versions

1.8.1

Priority

Minor