def service_snapshots(service_id)
      return unless service_id
      res = client.hgetall(redis_key(service_id))
      res.values.map{|v| Yajl::Parser.parse(v)}
    end
def service_snapshots(service_id)
      return unless service_id
      res = client.hgetall(redis_key(service_id))
      res.values.map{|v| Yajl::Parser.parse(v)}
    end
Get all snapshots related to a service instance