Starcluster config and plugin files for using the Disco MapReduce framework on EC2
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StarCluster Disco Plug-in

This plug-in, along with the associated Amazon EC2 AMI, make it
trivial to launch a Disco MapReduce cluster on EC2.  The Disco plug-in 
intializes Disco on a cluster, adds each cluster node to Disco, and
sets up data directories on the ephemeral drive for use by DDFS.

Quick Start

1) Install StarCluster (
2) Copy config.disco to ~/.starcluster/config
3) Add your Amazon credentials to the Starcluster config: 

  AWS_ACCESS_KEY_ID = # TODO: your key id
  AWS_SECRET_ACCESS_KEY = # TODO: your secret key
  AWS_USER_ID= # TODO: your account number
  # TODO: Add your keypair
  [key gsg-keypair]

4) Start a four node cluster

  $ starcluster start -s 4 disco-test
  < ... wait for the cluster to start ... >

5) View the Disco web interface on port 8989 of your cluster master

   http://<node id>

That's it!


The AMI ID for the StarCluster Disco Image is:  


This is based on the base x86_64 StarCluster AMI (ami-999d49f0) for
use with any 64-bit instance type (e.g., m1.large).

Config File Details

If you already have StarCluster installed, here are the additions
you'll need to make to your config file (in the order the sections

# Disco Image
NODE_IMAGE_ID = ami-84d10ced


# Tell StarCluster to use the Disco plugin
PLUGINS = disco_plugin


# Set custom Disco permissions


# Setup the Disco plugin
[plugin disco_plugin]
SETUP_CLASS = disco_plugin.ConfigDisco


# Set permissions to allow communication over port 8989
[permission disco]
from_port = 8989
to_port = 8989

Cluster Size for DDFS

The default Disco settings on the AMI use three copies of each DDFS
file.  DDFS will fail to startup correctly if there are fewer than
four nodes in the cluster (three workers, one master).

Using DDFS on Ephemeral Storage

The Disco plug-in uses the ephemeral storage under /mnt on each node
for DDFS.  The ephemeral storage is the fastest storage available to
a running instance and is equivalent to a local disk.  However, the
ephemeral storage is only available as long as the instance is
running.  As soon as the instance is stopped or terminated, the
ephemeral storage is removed.  

For Disco, as long as the cluster stays running, anything stored in
DDFS will be available to Disco.   Once the cluster goes down, either
by stopping it or terminating it, the DDFS volumes will cease to

A few possible ways allow the DDFS volumes to live beyond the life of
the cluster are:

- Add a step to copy the contents of DDFS to/from S3 or EBS when the
  cluster is launched and stopped.  This would require keeping the
  same number of nodes and also copying any Disco config information. 

- Mount EBS volumes on each node and use those for DDFS.  This option
  would make it easy to keep DDFS volumes intact but will degrade
  performance since EBS volumes are slower than ephemeral storage.

Neither of these options are implemented at the moment.  If you do
implement one, I will happily integrate it back into the plug-in.

AMI Details

The AMI is built on the base x86_64 StarCluster AMI (ami-999d49f0) for  
use with any 64-bit instance type (e.g., m1.large).

Disco was installed on the image following the standard instructions.
lighttpd was also installed, though the current Disco config is not
setup to use it.

Acknowledgements and Contact

The AMI was created by Chris Mueller to support the Disco tutorial at
PyData 2012.  

The video for the tutorial is online at:

The StarCluster plug-in was developed by Don MacMillen (primarily) and
Chris Mueller during the PyData Hack Night.

Thanks to Peter Wang and Travis Oliphant at Continuum Analytics for
organizing both events.

Contact Chris Mueller with any questions or comments related to the
plug-in.  cmueller at yahoo 

External Links

Amazon AWS: