def __distro(self):
        """Based on the Linux distribution, set values accordingly.  A user
        specified value overrides any defaults."""

        if hpccm.config.g_linux_distro == linux_distro.UBUNTU:
            if not self.__ospackages:
                self.__ospackages = ['byacc', 'file', 'flex', 'make',
                                     'openssh-client', 'wget']
            self.__runtime_ospackages = ['openssh-client']
        elif hpccm.config.g_linux_distro == linux_distro.CENTOS:
            if not self.__ospackages:
                self.__ospackages = ['byacc', 'file', 'flex', 'make',
                                     'openssh-clients', 'wget']
            self.__runtime_ospackages = ['openssh-clients']
        else: # pragma: no cover
            raise RuntimeError('Unknown Linux distribution')
Based on the Linux distribution, set values accordingly.  A user
        specified value overrides any defaults.
hpccm/building_blocks/mvapich2.py