test.pp

$my_hash = { 'foo1' => {'user' => 'a', 'pass' => 'p', 'ip' => '1.2.3.4'}, 'foo2' => {'user' => 'b', 'pass' => 'p', 'ip' => '4.5.6.7'}}

create_resources(do_thing, $my_hash)

define do_thing(user, pass, ip) {
  exec {'do_something':
    command => "ssh -l ${user} ${ip} < ${pass}"
  }
}

# ... will create two do_things, foo1 and foo2, with the specified params.