Usage:
  /usr/bin/clustercheck <user> <pass> <available_when_donor=0|1> <log_file> <available_when_readonly=0|1> <defaults_extra_file>
      Pass credentials directly on the command line. Default form, compatible
      with existing operator scripts.

  /usr/bin/clustercheck - <available_when_donor=0|1> <log_file> <available_when_readonly=0|1> <defaults_extra_file>
      Use '-' in place of <user> <pass> to keep credentials off the command
      line. The mysql client reads [client] user= and password= from
      <defaults_extra_file> (typically /etc/mysql/clustercheck.cnf, 0640
      root:mysql). Used by the systemd socket-activated clustercheck@.service
      shipped with PXC; see /usr/share/mysql/clustercheck.cnf.example.