Using MTO

The MUSCLE Transfer Overlay (MTO) is a daemon for forwarding traffic from MUSCLE 2. This service is often required when MUSCLE 2 is must communicate between several sites with firewall restrictions. On each site, a MTO should be placed on a node that is accessible within the cluster and from the outside world. Often, clusters have an interactive node that is suitable for this purpose.

If MTO is already installed, set up, and connected between all relevant sites, all that is needed from MUSCLE to use the MTO is to add the --intercluster flag to the command-line:

muscle2 -mc model.cxa.rb --intercluster sub1

The address that the simulation manager prints (suppose its 10.0.0.200:5002) can then directly be used on another site:

muscle2 -c model.cxa.rb --intercluster -M 10.0.0.200:5002 sub2

For convenience, the --intercluster flag also has the shorthand -i.

Configuration files

Before running MTO, its configuration files must be set to connect all clusters that will be used in a simulation.

MTO's configuration is stored in two files:

• global topology file (MUSCLE_HOME/etc/mto-topology.cfg)

  // Comment
  # Comment
  
  # host definiton
  # <name> <address> [<port>]
  # if port is ommited, this MTO will not listen for incomming connections
  
  A localhost
  B localhost 5100
  C localhost
  D localhost 5300
  

• local mto config file ( MUSCLE_HOME/etc/mto-config.cfg)

  # Name of this MTO as in mto-copology.cfg
  myName = A
  
  # Port range for clients of this MTO
  # Clients may register listening ports only from this range.
  # This range must not overlap any other MTO's range.
  localPortLow    = 5002
  localPortHigh   = 5099
  
  # Port and address where this MTO will listen for client requests.
  # Port and address for other MTO's is located in the topology file.
  internalPort    = 5001
  internalAddress = private-address
  

The global topology file states what clusters will be connected by the MTO, and on which port the MTO will communicate with other MTO's. It should be the same for all the MTO's participating. The local configuration states how the MTO can be contacted by MUSCLE within the cluster. It also implies that MUSCLE can only use a limited port range on a given cluster. Each cluster should use a different port range. To make this information available to MUSCLE 2, create the file MUSCLE_HOME/etc/muscle.defaults matching the mto-config.cfg file, containing

# Make the MTO available to MUSCLE.
export MUSCLE_MTO=private-address:5001
export MUSCLE_PORT_MIN=5002
export MUSCLE_PORT_MAX=5099

Whenever MUSCLE_HOME/etc/muscle.profile is sourced, these variables are set.

starting MTO

• debug mode

     mto --debug
  

• deamon mode

    mto
  

Example setup

Suppose we are using two domains, Amsterdam.nl (IP: 50.50.50.50) and Poznan.pl (IP: 100.100.100.100). For the former, we use port range 5000-5999, and it does not have any open ports but it can contact the latter, with port range 6000-6999 and an open port 20300. Then the global topology becomes

# <name> <address> [<port>]
Ams amsterdam.nl
Poz poznan.pl 20300

In Ams, we have the local configuration

myName = Ams
localPortLow    = 5002
localPortHigh   = 5999
internalPort    = 5001
internalAddress = 50.50.50.50

And in Poz, the configuration becomes:

myName = Poz
localPortLow    = 6002
localPortHigh   = 6999
internalPort    = 6001
internalAddress = 100.100.100.100

For this configuration to work, on Ams, port 5001 must not be used by another process and on Poz, port 6001 and port 20300 must be available.

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