ORBIT Basics ¶

Preparations ¶

Before you can complete any of the tutorials, you will need to have to do the following:

1. Make a reservation

   Wiki page "Tutorials/a0Basic/Documentation/Scheduler" does not exist

2. Login into reserved domain

   Login into reserved domain ¶

   During your approved time slot, you will be able to ssh into the console of the respective domain. A console is a dedicated machine that allows access to all resources in that domain.

   For example, to access the sandbox1:

   yourhost>ssh username@console.sb1.orbit-lab.org
   
   Using username "username".
   Authenticating with public key "xxxxxxxxx"
   Welcome to Ubuntu 12.04.1 LTS (GNU/Linux 3.2.0-36-generic x86_64)
   
    * Documentation:  https://help.ubuntu.com/
   
     System information as of Mon Jan 28 20:25:50 EST 2013
   
     System load:  0.0               Processes:           93
     Usage of /:   2.7% of 69.43GB   Users logged in:     0
     Memory usage: 6%                IP address for eth0: 10.50.18.10
     Swap usage:   0%                IP address for eth1: 10.18.0.10
   
     Graph this data and manage this system at https://landscape.canonical.com/
   
   9 packages can be updated.
   0 updates are security updates.
   
   |-----------------------------------------------------------------|
   |                 *** For authorized use only ***                 |
   | This system is for the use of authorized users only.  All users |
   | are expected to comply with the "Acceptable Use Policy" availa- |
   | ble at http://www.orbit-lab.org/AUP.html                        |
   | Individuals using this computer system, are subject to having   |
   | all of their activities on this system monitored and recorded   |
   | by system personnel.                                            |
   |                                                                 |
   | Anyone using this system expressly consents to such monitoring  |
   | and is advised that if such monitoring reveals possible         |
   | evidence of criminal activity, system personnel may provide the |
   | evidence of such monitoring to law enforcement officials.       |
   |                                                                 |
   | Email question, comments or problems to help@orbit-lab.org      |
   |-----------------------------------------------------------------|
   
   username@console.sb1:~$ 
   

3. Check the status

   omf stat ¶

   This omf command is used to display the power status of the node/domain.

   Usage: omf stat

   username@consoles.outdoor:omf stat
   Returns the status of the nodes in a testbed
   Usage:
         omf-5.4 stat [-h] [-s] [-t TOPOLOGY] [-c AGGREGATE]
    
         With: 
         -h, --help                print this help message
         -s, --summary             print a summary of the node status for the testbed
         -c, --config AGGREGATE    use testbed AGGREGATE
         -t, --topology TOPOLOGY   a valid topology file or description (defaults to 'system:topo:all')
    
         Some Examples: 
                       omf-5.4 stat
                       omf-5.4 stat -s
                       omf-5.4 stat -t omf.nicta.node1,omf.nicta.node2 -c sb1
                       omf-5.4 stat -t system:topo:all -c grid
   

   Individual nodes are identified in the output of stat command by their fully qualified domain name (FQDN). This establishes their "coordinates" and the "domain" to which they belong. Nodes in different domains typically can NOT see each other. Node can be in 1 of 3 states:

   POWEROFF	Node is Available for use but turned off
   POWERON	Node is Available and is on
   NOT REGISTERED	Node is not Available for use

   Example: omf stat on the outdoor domain

   user@console.outdoor:~# omf stat -t all
   
    INFO NodeHandler: OMF Experiment Controller 5.4 (git 6d34264)
    INFO NodeHandler: Slice ID: default_slice (default)
    INFO NodeHandler: Experiment ID: default_slice-2012-10-14t14.42.15-04.00
    INFO NodeHandler: Message authentication is disabled
    INFO Experiment: load system:exp:stdlib
    INFO property.resetDelay: value = 210 (Fixnum)
    INFO property.resetTries: value = 1 (Fixnum)
    INFO Experiment: load system:exp:eventlib
    INFO Experiment: load system:exp:stat
    INFO Topology: Loading topology ''.
    INFO property.nodes: value = "system:topo:all" (String)
    INFO property.summary: value = false (FalseClass)
    INFO Topology: Loading topology 'system:topo:all'.
    Talking to the CMC service, please wait
   -----------------------------------------------
    Domain: outdoor.orbit-lab.org
    Node: node3-6.outdoor.orbit-lab.org   	 State: NOT REGISTERED
    Node: node3-3.outdoor.orbit-lab.org   	 State: POWEROFF
    Node: node2-10.outdoor.orbit-lab.org    State: POWEROFF
    Node: node1-10.outdoor.orbit-lab.org    State: POWEROFF
    Node: node1-8.outdoor.orbit-lab.org   	 State: POWERON
    Node: node1-6.outdoor.orbit-lab.org   	 State: POWERON
    Node: node3-2.outdoor.orbit-lab.org   	 State: POWEROFF
    Node: node3-1.outdoor.orbit-lab.org   	 State: POWEROFF
    Node: node1-3.outdoor.orbit-lab.org   	 State: POWERON
    Node: node3-5.outdoor.orbit-lab.org   	 State: POWEROFF
    Node: node2-5.outdoor.orbit-lab.org   	 State: NOT REGISTERED
    Node: node1-2.outdoor.orbit-lab.org   	 State: POWERON
   -----------------------------------------------
    INFO Experiment: Switching ON resources which are OFF
    INFO EXPERIMENT_DONE: Event triggered. Starting the associated tasks.
    INFO NodeHandler: 
    INFO NodeHandler: Shutting down experiment, please wait...
    INFO NodeHandler: 
    INFO run: Experiment default_slice-2012-10-14t14.42.15-04.00 finished after 0:6
   

Managing Nodes ¶

• How to load (install) a disk image on a set of nodes

  Load an Image ¶

  1. Before we begin using the nodes, it's a good idea to check their status first. This is done with the omf stat command.

     omf stat ¶

     This omf command is used to display the power status of the node/domain.

     Usage: omf stat

     username@consoles.outdoor:omf stat
     Returns the status of the nodes in a testbed
     Usage:
           omf-5.4 stat [-h] [-s] [-t TOPOLOGY] [-c AGGREGATE]
      
           With: 
           -h, --help                print this help message
           -s, --summary             print a summary of the node status for the testbed
           -c, --config AGGREGATE    use testbed AGGREGATE
           -t, --topology TOPOLOGY   a valid topology file or description (defaults to 'system:topo:all')
      
           Some Examples: 
                         omf-5.4 stat
                         omf-5.4 stat -s
                         omf-5.4 stat -t omf.nicta.node1,omf.nicta.node2 -c sb1
                         omf-5.4 stat -t system:topo:all -c grid
     

     Individual nodes are identified in the output of stat command by their fully qualified domain name (FQDN). This establishes their "coordinates" and the "domain" to which they belong. Nodes in different domains typically can NOT see each other. Node can be in 1 of 3 states:

     POWEROFF	Node is Available for use but turned off
     POWERON	Node is Available and is on
     NOT REGISTERED	Node is not Available for use

     Example: omf stat on the outdoor domain

     user@console.outdoor:~# omf stat -t all
     
      INFO NodeHandler: OMF Experiment Controller 5.4 (git 6d34264)
      INFO NodeHandler: Slice ID: default_slice (default)
      INFO NodeHandler: Experiment ID: default_slice-2012-10-14t14.42.15-04.00
      INFO NodeHandler: Message authentication is disabled
      INFO Experiment: load system:exp:stdlib
      INFO property.resetDelay: value = 210 (Fixnum)
      INFO property.resetTries: value = 1 (Fixnum)
      INFO Experiment: load system:exp:eventlib
      INFO Experiment: load system:exp:stat
      INFO Topology: Loading topology ''.
      INFO property.nodes: value = "system:topo:all" (String)
      INFO property.summary: value = false (FalseClass)
      INFO Topology: Loading topology 'system:topo:all'.
      Talking to the CMC service, please wait
     -----------------------------------------------
      Domain: outdoor.orbit-lab.org
      Node: node3-6.outdoor.orbit-lab.org   	 State: NOT REGISTERED
      Node: node3-3.outdoor.orbit-lab.org   	 State: POWEROFF
      Node: node2-10.outdoor.orbit-lab.org    State: POWEROFF
      Node: node1-10.outdoor.orbit-lab.org    State: POWEROFF
      Node: node1-8.outdoor.orbit-lab.org   	 State: POWERON
      Node: node1-6.outdoor.orbit-lab.org   	 State: POWERON
      Node: node3-2.outdoor.orbit-lab.org   	 State: POWEROFF
      Node: node3-1.outdoor.orbit-lab.org   	 State: POWEROFF
      Node: node1-3.outdoor.orbit-lab.org   	 State: POWERON
      Node: node3-5.outdoor.orbit-lab.org   	 State: POWEROFF
      Node: node2-5.outdoor.orbit-lab.org   	 State: NOT REGISTERED
      Node: node1-2.outdoor.orbit-lab.org   	 State: POWERON
     -----------------------------------------------
      INFO Experiment: Switching ON resources which are OFF
      INFO EXPERIMENT_DONE: Event triggered. Starting the associated tasks.
      INFO NodeHandler: 
      INFO NodeHandler: Shutting down experiment, please wait...
      INFO NodeHandler: 
      INFO run: Experiment default_slice-2012-10-14t14.42.15-04.00 finished after 0:6
     

  2. It is recommended that the node be in the POWEROFF state prior to any experiment process. If the node is in the POWERON state you can use the omf tell command to get the node into the off state.

     omf tell ¶

     OMF command to control the power state/reset the nodes.

     Usage: omf tell

     user@console:omf tell
     Switch ON/OFF and reboot the nodes in a testbed
     Usage:
           omf tell [-h] -t TOPOLOGY -a ACTION [-c AGGREGATE]
      
           With: 
           -h, --help           print this help message
      
           -a, --action ACTION  specify an action
           ACTION:
           on              turn node(s) ON
           offs            turn node(s) OFF (soft)
           offh            turn node(s) OFF (hard)
           reboot          reboots node(s) (soft)
           reset           resets node(s) (hard)
      
           -h, --help                print this help message
           -t, --topology TOPOLOGY   a valid topology file or description (MANDATORY)
           -c, --config AGGREGATE    use testbed AGGREGATE
      
           Some Examples: 
                         omf tell -a reset -t node1-1.grid.orbit-lab.org
                         omf tell -a on -t system:topo:all -c grid
                         omf tell -a reboot -t node1-1
                         omf tell -a offh -t [1..2,1..5]
                         omf tell -a offh -t system:topo:all
                         omf tell -a reset -t system:topo:imaged
     

     The commands are: on, offh (equivalent to pulling out the power cord), offs (software shutdown), reboot (software reboot) and reset (hardware reset).

     Example: turn off node1-1 on the outdoor domain

     user@console.outdoor:~# omf tell -a offh -t node1-1
     
      INFO NodeHandler: OMF Experiment Controller 5.4 (git 3fb37b9)
      INFO NodeHandler: Reading configuration file /etc/omf-expctl-5.4/services.yaml
      INFO NodeHandler: Add domain http - http://internal1.orbit-lab.org:5054/
      INFO NodeHandler: Add domain http - http://repository1.orbit-lab.org:5054/
      INFO NodeHandler: Slice ID: default_slice (default)
      INFO NodeHandler: Experiment ID: default_slice-2014-09-30t00.24.28.504-04.00
      INFO NodeHandler: Message authentication is disabled
      INFO Experiment: load system:exp:stdlib
      INFO property.resetDelay: resetDelay = 230 (Fixnum)
      INFO property.resetTries: resetTries = 1 (Fixnum)
      INFO Experiment: load system:exp:eventlib
      INFO Experiment: load system:exp:winlib
      INFO Experiment: load system:exp:tell
      INFO property.nodes: nodes = "node1-1" (String)
      INFO property.command: command = "offh" (String)
     
     Talking to the CMC service, please wait
     -----------------------------------------------
      Node: node1-1.outdoor.orbit-lab.org   	 Reply: OK
     -----------------------------------------------
     
      INFO EXPERIMENT_DONE: Event triggered. Starting the associated tasks.
      INFO NodeHandler: 
      INFO NodeHandler: Shutting down experiment, please wait...
      INFO NodeHandler: 
      INFO run: Experiment default_slice-2014-09-30t00.24.28.504-04.00 finished after 0:10
     

  3. Once node set is on an POWEROFF state, load an image with omf load command

     omf load ¶

     Load command is used to put an image onto the hard disk of the node.

     Usage: omf load

     Install a given disk image on the nodes in a testbed
     Usage:
           omf-5.4 load [-h] [-i IMAGE_PATH] [-o TIMEOUT] [-t TOPOLOGY] [-c AGGREGATE]
      
           With: 
           -h, --help                print this help message
           -c, --config AGGREGATE    use testbed AGGREGATE
           -t, --topology TOPOLOGY   a valid topology file or description (defaults to 'system:topo:all')
                                     (if a file 'TOPOLOGY' doesn't exist, interpret it as a comma-separated list of nodes)
           -i, --image IMAGE         disk image to load
                                     (default is 'baseline.ndz', the latest stable baseline image)
           -o, --timeout TIMEOUT     a duration (in sec.) after which imageNodes should stop waiting for
                                     nodes that have not finished their image installation
                                     (default is 800 sec, i.e. 13min 20sec)
               --outpath PATH        Path where the resulting Topologies should be saved
                                     (default is '/tmp')
               --outprefix PREFIX    Prefix to use for naming the resulting Topologies
                                     (default is your experiment ID)
      
           Some Examples: 
                         omf-5.4 load
                         omf-5.4 load -t system:topo:all -i baseline-2.4.ndz
                         omf-5.4 load -t omf.nicta.node1 -i wireless-2.6.ndz
                         omf-5.4 load -t omf.nicta.node1,omf.nicta.node2 -i baseline.ndz -o 400
                         omf-5.4 load -t system:topo:circle -i my_Own_Image.ndz
                         omf-5.4 load -t my_Own_Topology -i baseline-2.2.ndz -t 600 -c grid
                         omf-5.4 load -t my_Own_Topology --outpath ./ --outprefix my_Own_Prefix
     

     Two important arguments are TOPOLOGY describing the set of nodes one wishes to image , and !IMAGE specifying the name of the image one wants to load the nodes with. If the imaging process does not does not finish within the default timeout period, that period can be increase by using the -o flag (e.g. -o 1600). Typical command to load both nodes of sandbox 1 with the baseline image would look like:

     Example: omf load-i baseline.ndz -t node1-1

     username@console.sb3:~$ omf load -i baseline.ndz -t node1-1
     
     DEBUG FQDN:console.sb3.orbit-lab.org:
      INFO NodeHandler: OMF Experiment Controller 5.4 (git 861d645)
      INFO NodeHandler: Reading configuration file /etc/omf-expctl-5.4/services.yaml
      INFO NodeHandler: Add domain http - http://internal1.orbit-lab.org:5054/
      INFO NodeHandler: Add domain http - http://repository1.orbit-lab.org:5054/
      INFO NodeHandler: Add domain http - http://external1.orbit-lab.org:5054/
      INFO NodeHandler: Slice ID: pxe_slice
      INFO NodeHandler: Experiment ID: pxe_slice-2018-08-08t13.41.37.814-04.00
      INFO NodeHandler: Message authentication is disabled
      INFO Experiment: load system:exp:stdlib
      INFO property.resetDelay: resetDelay = 230 (Fixnum)
      INFO property.resetTries: resetTries = 1 (Fixnum)
      INFO Experiment: load system:exp:eventlib
      INFO Experiment: load system:exp:winlib
      INFO Experiment: load system:exp:imageNode
      INFO property.nodes: nodes = "node1-1" (String)
      INFO property.image: image = "baseline.ndz" (String)
      INFO property.domain: domain = "sb3.orbit-lab.org" (String)
      INFO property.outpath: outpath = "/tmp" (String)
      INFO property.outprefix: outprefix = "pxe_slice-2018-08-08t13.41.37.814-04.00" (String)
      INFO property.timeout: timeout = 800 (Fixnum)
      INFO property.resize: resize = nil (NilClass)
      INFO Topology: Loaded topology 'system:topo:registered'.
      INFO property.resetDelay: resetDelay = 100 (Fixnum)
      INFO Experiment: Resetting resources
      INFO stdlib: Waiting for nodes (Up/Down/Total): 0/1/1 - (still down: node1-1.sb3.orbit-lab.org) [0 sec.]
      INFO stdlib: Waiting for nodes (Up/Down/Total): 0/1/1 - (still down: node1-1.sb3.orbit-lab.org) [10 sec.]
      INFO stdlib: Waiting for nodes (Up/Down/Total): 0/1/1 - (still down: node1-1.sb3.orbit-lab.org) [20 sec.]
      INFO stdlib: Waiting for nodes (Up/Down/Total): 0/1/1 - (still down: node1-1.sb3.orbit-lab.org) [30 sec.]
      INFO stdlib: Waiting for nodes (Up/Down/Total): 0/1/1 - (still down: node1-1.sb3.orbit-lab.org) [40 sec.]
      INFO stdlib: Waiting for nodes (Up/Down/Total): 0/1/1 - (still down: node1-1.sb3.orbit-lab.org) [50 sec.]
      INFO exp: Progress(0/0/1): 0/0/0 min(node1-1.sb3.orbit-lab.org)/avg/max (59) - Timeout: 790 sec.
      INFO ALL_UP: Event triggered. Starting the associated tasks.
      INFO BRING_UP: Event triggered. Starting the associated tasks.
      INFO Experiment: Bringing up resources
      INFO exp: Progress(0/0/1): 50/50/50 min(node1-1.sb3.orbit-lab.org)/avg/max (59) - Timeout: 780 sec.
      INFO exp: Progress(0/0/1): 80/80/80 min(node1-1.sb3.orbit-lab.org)/avg/max (59) - Timeout: 770 sec.
      INFO exp: Progress(1/0/1): 100/100/100 min()/avg/max (59) - Timeout: 760 sec.
      INFO exp:  -----------------------------
      INFO exp:  Imaging Process Done
      INFO exp:  1 node successfully imaged - Topology saved in '/tmp/pxe_slice-2018-08-08t13.41.37.814-04.00-topo-success.rb'
      INFO exp:  -----------------------------
      INFO EXPERIMENT_DONE: Event triggered. Starting the associated tasks.
      INFO NodeHandler:
      INFO NodeHandler: Shutting down experiment, please wait...
      INFO NodeHandler:
      INFO NodeHandler: Shutdown flag is set - Turning Off the resources
      INFO run: Experiment pxe_slice-2018-08-08t13.41.37.814-04.00 finished after 1:44
     
     

     If the node is in the NOT REGISTERED state, you may need to wait for it to recover the POWEROFF state (it some times requires a few moments for the services to sync up). If the node takes more than 60 seconds to come out of the NODE NOT AVAILABLE state please report it to an administrator.

• How to save an existing disk image from one node

  How to save a disk image from one node of a Testbed ¶

  Once you have the image prepared the way you want it. On the node run:

  ssh root@node1-1.sb1.orbit-lab.org
  root@node1-1.sb1.orbit-lab.org: ./prepare.sh
  

  This will remove udev rules (to prevent renaming of interfaces) and dump log files to lower the size of the image. It will also shutdown the node.

  Once the node has been shutdown, to save the existing disk image on node (1,1) of the 'sb1' testbed, use the command:

   omf save -n node1-1.sb1.orbit-lab.org 
   # will save the current disk image on node [1,1] of the 'sb1' testbed
  
  

  The output of this image saving process will look like the following:

  INFO NodeHandler: OMF Experiment Controller 5.4 (git c005675)
  INFO NodeHandler: Slice ID: pxe_slice 
  INFO NodeHandler: Experiment ID: pxe_slice-2013-02-06t14.14.46-05.00
  INFO NodeHandler: Message authentication is disabled
  INFO Experiment: load system:exp:stdlib
  INFO property.resetDelay: resetDelay = 230 (Fixnum)
  INFO property.resetTries: resetTries = 1 (Fixnum)
  INFO Experiment: load system:exp:eventlib
  INFO Experiment: load system:exp:saveNode
  INFO property.node: node = "node1-1.sb1.orbit-lab.org" (String)
  INFO property.pxe: pxe = "1.1.6" (String)
  INFO property.domain: domain = "grid.orbit-lab.org" (String)
  INFO property.started: started = "false" (String)
  INFO property.image: image = nil (NilClass)
  INFO property.resize: resize = nil (NilClass)
  WARN exp: Saving only works for ext2/ext3 partitions and MBR (msdos) partition tables. Saving any other filesystem or partition table type will produce a 0 byte image.
  INFO Topology: Loading topology 'node1-1.sb1.orbit-lab.org'.
  INFO Experiment: Resetting resources
  INFO stdlib: Waiting for nodes (Up/Down/Total): 0/1/1 - (still down: node1-1.sb1.orbit-lab.org) [0 sec.]
  .
  .
  .
  INFO stdlib: Waiting for nodes (Up/Down/Total): 0/1/1 - (still down: node1-1.sb1.orbit-lab.org) [80 sec.]
  INFO ALL_UP: Event triggered. Starting the associated tasks.
  INFO node1-1.sb1.orbit-lab.org:  
  INFO node1-1.sb1.orbit-lab.org: - Saving image of '/dev/sda' on node 'node1-1.sb1.orbit-lab.org'
  INFO node1-1.sb1.orbit-lab.org:   to the file 'bob-node-node1-1.sb1.orbit-lab.org-2013-02-06-14-16-23.ndz' on host '10.10.0.42'
  INFO node1-1.sb1.orbit-lab.org:  
  INFO property.started: started = "true" (String)
  INFO exp:  
  INFO exp: - Saving process started at: Wed Feb 06 14:16:27 -0500 2013
  INFO exp:   (this may take a while depending on the size of your image)
  INFO Experiment: DONE!
  INFO ExecApp: Application 'commServer' finished
  INFO run: Experiment sb1_2008_07_20_23_38_04 finished after 9:19
  done.
  
  

  At the end of the saving process, you will have disk image file with the name: "bob-node-node1-1.sb1.orbit-lab.org-2013-02-06-14-16-23.ndz" in the directory "/mnt/images" on the machine with the host name "repository1". These information are all provided in the output displayed above.

  You can then:

  • install this disk image on a set of nodes, using the instructions described in this tutorial. In this example, to install the newly created disk image on node (1,2):

      omf load -t node1-2.sb1.orbit-lab.org -i bob-node-node1-1.sb1.orbit-lab.org-2013-02-06-14-16-23.ndz
      # will install the disk image on node [1,2] of the 'sb1' testbed
    
    

  • only for the purpose of making a backup of your image: log into the "repository" machine, and copy your image to your backup storage.

  
  

  Learning More ¶

  The above disk image saving process is implemented as a special orbit experiment. As such, its execution will results in a log file as with any other orbit experiment. This log file should look like this​.

  Each image created by the above saving process is a full hard-disk image, which can have arbitrary large file size (>200Mo or even more). As storage on the "frisbee" machine is limited, please be considerate in the number of images you save/use, and move any unused images to your own archival storage.

  The generic omf command used above is the access point to control various ORBIT functions, such as the saving of a disk image from a node, with the sub-command "save". To see a list of all the available omf commands, you should type "omf help".

  Finally, the complete available option/commands for the save function are given by "omf help save":

  omf save --help
  Save a disk image from a given node into an archive file
  Usage:
        omf save -n NODE [-h] [-c AGGREGATE]
   
        With: 
        -h, --help          print this help message
        -n, --node NODE     a valid description of a single node (MANDATORY)
                            (no default here, you have to enter a node!)
        -r, --resize SIZE   Resizes the first partition to SIZE GB or to maximum size if SIZE=0 or
                            leave x percent of free space if SIZE=x%
   
        Some Examples: 
                      omf save -n node5-3.grid.orbit-lab.org
                      omf save -n node1-1.sb2.orbit-lab.org
   
  

• How to switch On/Off a set of nodes

  How to switch On/Off the nodes of a Testbed ¶

  To switch some nodes On/Off on the 'grid' testbed, use the command:

  omf tell -a on -t all
  

  will turn On the entire set of 20x20 nodes on the grid.

  omf tell -a offs -t node3-1.grid.orbit-lab.org,node5-6.grid.orbit-lab.org,node1-1.grid.orbit-lab.org,node1-2.grid.orbit-lab.org
  

  will turn Off (soft, that is attempt a graceful shutdown) the nodes 3,1 and 5,6 and 1,1 and 1,2

  omf tell -a offh -t node3-1.grid.orbit-lab.org,node5-6.grid.orbit-lab.org,node1-1.grid.orbit-lab.org,node1-2.grid.orbit-lab.org
  

  will turn Off (hard, that is "hold down" the power button) the nodes 3,1 and 5,6 and 1,1 and 1,2

  Learning More ¶

  The complete available options for this command is given by "omf help tell":

   user@console.grid:~$ omf help tell
   Switch ON/OFF and reboot the nodes in a testbed
   Usage:
        omf tell -a ACTION [-h] [-t TOPOLOGY] [-c AGGREGATE]
   
        With: 
        -h, --help           print this help message
   
        -a, --action ACTION  specify an action
        ACTION:
        on              turn node(s) ON
        offs            turn node(s) OFF (soft)
        offh            turn node(s) OFF (hard)
        reboot          reboots node(s) (soft)
        reset           resets node(s) (hard)
   
        -c, --config AGGREGATE    use testbed AGGREGATE
        -t, --topology TOPOLOGY   a valid topology file or description (defaults to 'system:topo:all')
   
        Some Examples: 
                      omf tell -a reset
                      omf tell -a on -t system:topo:all -c grid
                      omf tell -a reboot -t omf.nicta.node1
                      omf tell -a offs -t omf.nicta.node1,omf.nicta.node2 -c sb1
                      omf tell -a offh -t system:topo:all
                      omf tell -a reset -t topo_grid_active
  

  Of particular interest is the -t flag which can be used to specify arbitrary topolgies. These can be of the form "nodex1-y1.fqdn,nodex2-y2.fqdn,…"