ec2metadata fails with traceback within ensemble nodes

On nodes that have been bootstrapped via ensemble, ec2metadata fails with the following traceback:

# ec2metadata
ami-e7c5048e
0
(unknown)
unavailable
us-east-1b
ami
ephemeral0
root
swap
none
i-97e895f6
m1.small
ip-10-72-203-28.ec2.internal
10.72.203.28
aki-805ea7e9
12:31:39:24:cb:ee
default-paravirtual
unavailable
ec2-184-73-62-175.compute-1.amazonaws.com
184.73.62.175
Traceback (most recent call last):
  File "/usr/bin/ec2metadata", line 212, in <module>
    main()
  File "/usr/bin/ec2metadata", line 208, in main
    display(metaopts, burl)
  File "/usr/bin/ec2metadata", line 164, in display
    value = m.get(metaopt)
  File "/usr/bin/ec2metadata", line 139, in get
    keyids = [ line.split('=')[0] for line in data.splitlines() ]
AttributeError: 'NoneType' object has no attribute 'splitlines'

The following userdata is injected into image via ensemble:

#part-000
#cloud-config
apt-update: true
apt-upgrade: true
apt_sources:
- {source: 'ppa:ensemble/ppa'}
machine-data: {ensemble-provider-type: ec2, ensemble-zookeeper-hosts: 'ip-10-85-67-223.ec2.internal:2181',
  machine-id: 14}
packages: [bzr, tmux, python-setuptools, python-twisted, python-argparse, python-txaws,
  python-zookeeper]
runcmd: [sudo apt-get -y install ensemble, sudo mkdir -p /var/lib/ensemble, sudo mkdir
    -p /var/log/ensemble, 'ENSEMBLE_MACHINE_ID=14 ENSEMBLE_ZOOKEEPER=ip-10-85-67-223.ec2.internal:2181
    python -m ensemble.agents.machine -n --logfile=/var/log/ensemble/machine-agent.log
    --pidfile=/var/run/ensemble/machine-agent.pid']
ssh_authorized_keys: ['ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQC27Us7lSjCpa7bumXAgcT1CMVTJPKZAVahcsroMghwV23CMmVz/rR7+vJ8SHdPDbBQY8ZpY2rREDzc9k2YyI+PzL189JvUMQhQ3n2iByfSrhWbvGygSTtY06cAfZG4ln2zCIe30k6YJzglYMwMPAdbFPoJS5wXCoJ+vaxQT3lUuoJ+s4JyMoQkm2Em62TBHsFLtrtrX2p1d932i6jVDOOM9+Aa4q2HpojxvxOUZX83xLCZQYMdkVE+c/vdDNZ4UlpOw2hRYlHi95ofXwoQeXwQv6vfFw5SjZDkXzduhjbOxGkoPmfVpKz081Vxchakb2P+ayxziqyDiQcfRRF4QDep