'Get a set of all namespaces on host managed by this manager.'

def list_all(self):

    try:
        root_ip = ip_lib.IPWrapper()
        namespaces = root_ip.get_namespaces()
        return set((ns for ns in namespaces if self.is_managed(ns)))
    except RuntimeError:
        LOG.exception(_LE('RuntimeError    in    obtaining    namespace    list    for    namespace    cleanup.'))
        return set()
