* PMIX_CONNECT_ID_MODIFIER_PREPEND: modify the nspace returned by the host by prepending the given modifier to the nspace string. This allows the application to "tag" the connected group in a recognizable fashion.

* PMIX_CONNECT_ID_MODIFIER_APPEND: modify the nspace returned by the host by appending the given modifier to the nspace string. This allows the application to "tag" the connected group in a recognizable fashion.

* PMIX_CONNECT_ID_REQUEST: request that the given identifier be used as the assigned nspace for the connected group. The "required" flag in the directive can be used to indicate that this identifier is required (i.e., the host RM must use it for the group, returning an error if it is already in use) as opposed to requested (i.e., the host RM can substitute its own unique identifier if the specified one is already in use).

I also added the PMIX_CLUSTER_ID attribute to the list of information to be provided by the RM at process start - you can see the list here:

Ralph