A first container executing on a first computer determines, by using one or more messages defined by an open-standard protocol and communicated over one or more networks coupled to the second computer, whether the second container, executing on a second computer, can communicate using messages having a portion not defined by the open-standard protocol and having a portion defined by the open-standard protocol. The first container communicates, with the second container, at least one additional message having the portion not defined by the open-standard protocol and having the portion defined by the open-standard protocol. The portion not defined by the open-standard protocol occupies a predetermined part of the message that would be defined by the open-standard protocol if the open-standard protocol were used for the predetermined part.