Group Experimentation Support

Experiment scheduler

Installing and configuring packages on Ubuntu

This section describes how to set up torque PBS. If it's already set up, skip this section. First, we install the torque PSB system:

apt-get install torque-server torque-scheduler torque-mom torque-client

Then stop all the running torque processes:

/etc/init.d/torque-mom stop
/etc/init.d/torque-scheduler stop
/etc/init.d/torque-server stop

Create the PBS server (say "yes" when prompted):

pbs_server -t create

Then kill the PBS server process:

killall pbs_server

Set up the PBS server:

echo $(hostname -f) > /etc/torque/server_name
echo $(hostname -f) >  /var/spool/torque/server_priv/acl_svr/acl_hosts
echo $(hostname -f) > /var/spool/torque/mom_priv/config

echo root@$(hostname -f) > /var/spool/torque/server_priv/acl_svr/operators
echo root@$(hostname -f) > /var/spool/torque/server_priv/acl_svr/managers

echo "$(hostname -f) np=4" > /var/spool/torque/server_priv/nodes

If you have a line in your /etc/hosts file that resolves your hostname to 127.0.1.1, you have to comment it out, e.g.

#127.0.1.1  console.grid.orbit-lab.org  console

Once you've done that, start everything back up again:

/etc/init.d/torque-server start
/etc/init.d/torque-scheduler start
/etc/init.d/torque-mom start

Now we'll set up some configuration values:

qmgr -c "set server scheduling = True"
qmgr -c "set server acl_host_enable = True"
qmgr -c "set server acl_hosts = $(hostname -f)"
qmgr -c "set server allow_node_submit = True"

You'll have to run the commands above as root, since you've set up the root user as the only PBS operator and manager.

Next we'll set up queues: one for each node.

For various reasons, we've decided to make a queue per node and have the console be the single "compute" node, instead of having the nodes be the "compute" nodes. (Mainly because then we can still use legacy disk images, and don't have to worry about configuring the nodes to work with torque.) It might seem "neater" to use "nodes" instead of queues, because this would make it simpler to run an experiment with multiple nodes. In practice, though, it would still be annoying to run an experiment with multiple nodes because you generally care which nodes in this scenario (e.g. you want nodes that are close.)

First we get a list of nodes, then we'll set up a queue for each one:

list=$(omf stat -t system:topo:all | grep "Node:" | awk -F" " '{print $2}' | cut -f1 -d$'.')

for l in $list
do 
    qmgr -c "create queue $l"
    qmgr -c "set queue $l queue_type = Execution"
    qmgr -c "set queue $l max_running = 1"
    qmgr -c "set queue $l enabled = True"
    qmgr -c "set queue $l started = True"
done

(Again, this must be done as root or as a queue manager.)

Now we'll disable all the queues, because we are going to re-enable them selectively.

list=$(qstat -Q | tail -n+3 | awk -F" " '{print $1}')

for l in $list
do 
    qdisable "$l"
done

Check with

qstat -Q

Scheduler utility script

Enabling/disabling "scheduled" experiments

The easiest way to turn the scheduler on and off is to put the scheduler utility script in /usr/local/bin/omf. When you want it to be turned on, make it executable:

chmod a+x /usr/local/bin/omf

and when you want it to be turned off, turn off the execute bit:

chmod a-x /usr/local/bin/omf

On WITest, as part of the script that runs at the beginning of each reservation, the scheduler script is turned on if it is a group reservation and off if it isn't, and all queues are disabled.

It is then up to the group "leader" (i.e. tutorial instructor, teaching assistant, etc.) to enable individual queues for the experiment that the group will run. The group "leader" also needs to know to use the full path /usr/bin/omf for "load" commands, which are disabled in the utility script (because it is generally not desirable to load images in a group reservation.)

Making OMF scripts that work with the scheduler

To work with the scheduler utility script, the OMF experiment script should define a property 'node' that specifies the resource to use. This should also be the name of a queue. For an experiment that requires multiple resources, they should be specified with e.g. a dictionary.

For example, this script defines a "sndnode" and a "rcvnode":

defProperty('prefix', '', "Prefix for HRN")
defProperty('suffix', '.grid.orbit-lab.org', "Suffix for HRN")
defProperty('node', 'node3-19', "ID of sender node, will be passed by job scheduler")

# Set up node pair
sndnode = "#{property.prefix}#{property.node}#{property.suffix}"
assignments = {"node3-19" => "node3-18", "node14-10" => "node14-11"}
rcvnode = assignments["#{property.node}"].to_s

Using the scheduler

Some important commands follow.

To enable a queue named e.g. node13-10 so that it starts accepting jobs (user must be listed as a torque operator or manager):

qenable node13-10

To disable a queue named e.g. node13-10 so that it will finish currently queued jobs but not accept new ones (user must be listed as a torque operator or manager):

qdisable node13-10

To see the current torque server configuration:

qmgr -c 'p s'

To add a user e.g. ffund01 as a torque manager:

qmgr -c "set server managers += ffund@console.grid.orbit-lab.org"

To kill a job with job ID e.g. 13:

qdel 13

To see currently queued and running jobs (all if you're a torque manager, otherwise your own):

qstat

OMF with reporting

Patching OMF EC

Usage instructions

Experiment dashboard

Installing/configuring packages on Ubuntu

Install a JavaScript runtime:

sudo apt-get install nodejs

Get the ​dashing gem:

gem install dashing
gem install bundler
gem install execjs --version 1.4.0  # see https://github.com/Shopify/dashing/issues/195
gem uninstall execjs --version 2.0.2

In the dashing gemspec (wherever it is located), you may have to change the version for the "execjs" dependency to 1.4.0.

Get the source code for the dashboard. cd to that directory, then run

bundle
dashing start

Source code for experiment dashboard

Usage