checkNotNull(instanceTemplate);
checkArgument(instanceTemplate.getNumberOfInstances() == 1);
Set<? extends NodeMetadata> nodes;
try {
LOG.info("Starting master node");
nodes = computeService.runNodesWithTag(
clusterSpec.getClusterName(), 1, masterTemplate);
LOG.info("Master node started: {}", nodes);
} catch (RunNodesException e) {
// TODO: can we do better here (retry?)
throw new IOException(e);